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1. (WO2019027366) ANTIMICROBIAL PEPTIDOMIMETICS
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Antimicrobial Peptidomimetics

TECHNICAL FIELD

[0001] The present invention relates to compounds, compositions, and methods for treating diseases and conditions. In particular, the invention relates to compounds, compositions, and methods for treating bacterial infections, disorders and conditions.

BACKGROUND

[0002] In 2011, there were 80,000 cases of invasive Meticillin-resistant Staphylococcus aureus (MRS A) infections in the United States, resulting in 11,000 fatalities. The emergence of multi-drug-resistant bacteria and the lack of new antibiotics in the drug development pipelines of pharmaceutical companies is a major health concern. Since 2000, only four antibiotics with new chemical scaffolds were launched; the (i) oxazolidinone Linezolid (2000), (ii) lipopeptide Daptomycin (2003), (iii) pleuromutilin Retapamulin (2007) and (iv) macrocycle Fidaxomicin (2011). Hence, there is an urgent need to develop new classes of antibacterials, especially those against emerging multi-drug-resistant bacteria. Staphylococcus aureus (SA) is also the primary culprit responsible for human skin and soft tissue infections (SSTIs). A study involving 11 US hospitals revealed more than 75% of SSTI cases were caused by Staphylococcus aureus and close to 60% were found to involve Meticillin-resistant Staphylococcus aureus (MRS A). Of particular concern is the emergence of Mupirocin-resistant MRSA, a front-line widely-used topical antibiotic used for the treatment of MRSA skin infections and nasal decolonization. At Singapore's Tan Tock Seng hospital, the prevalence of Mupirocin-resistant MRSA was 11% in a 2009-2010 survey. Alarmingly, a more recent 2013 survey by 7 public-sector hospitals in Singapore revealed a 31% incidence rate, mirroring a 2012-2013 survey at a New York City hospital. The highest rate of Mupirocin resistance ever reported was 79% in 2008 in a Swiss hospital. With these alarming statistics, it is imperative that a Mupirocin substitute be developed as soon as possible.

SUMMARY

[0003] Novel compounds have now been found with superior anti-bactericidal activities.

[0004] In one aspect, there is provided a compound of formula (I):


or a pharmaceutically acceptable salt or solvate thereof;

wherein Li is -(CH2)m-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein m is selected from 1 to 5;

wherein Ri and R2 are independently selected from H or CH3, or

Ri is selected from H or CH3 and R2 is


wherein L2 is -(ϋ¾)η-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein n is selected from 1 to5;

wherein R3-R8 are independently H, CI, I, Br or F;

wherein at least one of R -R8 is CI, I, Br or F;

wherein Rg is ~ ~>-

wherein L3 is -(CEb , C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein o is selected from 1 to 5;

wherein L4 is -(CH2)P-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein p is selected from 1 to5;

wherein Rio, Rn and R12 are independently H or -CH3.

BRIEF DESCRIPTION OF THE FIGURES

[0005] Figure 1 shows a time-kill assay using compounds at 4x MIC concentration on Mupirocin-resistant MRSA (ATCC-BAA-1556).

[0006] Figure 2 shows a bactericidal/static determination assay at 4x MIC concentration using Mupirocin-resistant MRSA (ATCC-BAA-1556); (A) Linezolid; (B) Retapamulin; (C) Vancomycin; (D) Compound 34.

[0007] Figure 3 shows the minimum bactericidal concentration determination of Compound 34 using Mupirocin-resistant MRSA (ATCC-BAA-1556); (A) at MIC; (B) at 2x MIC.

[0008] Figure 4 shows an electrospray ionization-mass spectrum (ESI-MS) of Compound 34.

[0009] Figure 5 shows a nuclear magnetic resonance (NMR) spectrum of Compound 34.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

[00010] The following are some definitions that may be helpful in understanding the description of the present invention. These are intended as general definitions and should in no way limit the scope of the present invention to those terms alone, but are put forth for a better understanding of the following description.

[00011] Unless the context requires otherwise or specifically stated to the contrary, integers, steps, or elements of the invention recited herein as singular integers, steps or elements clearly encompass both singular and plural forms of the recited integers, steps or elements.

[00012] Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated step or element or integer or group of steps or elements or integers, but not the exclusion of any other step or element or integer or group of elements or integers. Thus, in the context of this specification, the term "comprising" means "including principally, but not necessarily solely".

[00013] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

[00014] The term "cycloalkyl" as used herein refers to cyclic saturated aliphatic groups and includes within its meaning monovalent ("cycloalkyl"), and divalent ("cycloalkylene"), saturated, monocyclic, bicyclic, polycyclic or fused polycyclic hydrocarbon radicals having from 3 to 10 carbon atoms, e.g., 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. Examples of monovalent cycloalkyl groups include but are not limited to cyclopropyl, 2-methylcyclopropyl, cyclobutyl, cyclopentyl, 2-methylcyclopentyl, 3-methylcyclopentyl, cyclohexyl, and the like. Examples of divalent cycloalkylene groups include but are not limited to cyclopropylene, 2-methylcyclopropylene, cyclobutylene, cyclopentylene, 2-methylcyclopentylene, 3-methylcyclopentylene, cyclohexylene, and the like.

[00015] "Alkenylene" refers to divalent alkenyl groups preferably having from 2 to 8 carbon atoms and more preferably 2 to 6 carbon atoms. Examples include ethenylene (-CH=CH-), and the propenylene isomers (e.g., -CH2CH=CH- and -C(CH3)=CH-), and the like.

[00016] "Alkynylene" refers to the divalent alkynyl groups preferably having from 2 to 8 carbon atoms and more preferably 2 to 6 carbon atoms. Examples include ethynylene (-C≡C-), propynylene (-CH2-C≡C-), and the like.

[00017] The term "phenylene" as used herein refers to a divalent benzene moiety.

"benzylene" as used herein refers to a divalent benzyl moiety of the


[00019] The present invention includes within its scope all isomeric forms of the compounds disclosed herein, including all diastereomeric isomers, racemates and enantiomers, unless the stereochemistry is fixed in the formula drawing. Thus, formula (I) should be understood to include, for example, E, Z, cis, trans, (R), (S), (L), (D), (+), and/or (-) forms of the compounds, as appropriate in each case, unless the stereochemistry is fixed in the formula drawing.

[00020] The term "Fmoc" or "fmoc" in the formulas and description refers to a typical fluorenylmethyloxycarbonyl protecting group.

[00021] The term "t-Boc" or "Boc" in the formulas and description refers to a typical tert-butoxycarbonyl protecting group.

[00022] The term "Pbf" stands for a 2,2,4, 6,7 -pentamethyldihydrobenzofuran-5-sulfonyl protecting group.

[00023] The term "a compound of formula (I) or a salt or solvate thereof" or "a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof" is intended to identify a compound selected from the group consisting of: a compound of the formula (I), a salt of a compound of formula (I), a pharmaceutically acceptable solvate of a compound of formula (I) or a pharmaceutically acceptable solvate of a pharmaceutically acceptable salt of a compound of formula (I).

[00024] The term "therapeutically effective" is intended to qualify the amount of compound or pharmaceutical composition, or the combined amount of active ingredients in the case of combination therapy.

[00025] The term "treatment" as used herein to describe the present invention und unless otherwise qualified, means administration of the compound, pharmaceutical composition or combination to effect preventive, palliative, supportive, restorative or curative treatment.

[00026] The term "preventive treatment" as used herein to describe the present invention, means that the compound, pharmaceutical composition or combination is administered to a subject or member of a population that is significantly predisposed to the relevant condition.

[00027] The term "palliative treatment" as used herein to describe the present invention, means that the compound, pharmaceutical composition or combination is administered to a subject to remedy signs and/or symptoms of a condition, without necessarily modifying the progression of, or underlying etiology of, the relevant condition. Non-limiting examples include reduction of pain, discomfort, swelling or fever.

[00028] The term "supportive treatment" as used herein to describe the present invention, means that the compound, pharmaceutical composition or combination is administered to a subject as part of a regimen of therapy, but that such therapy is not limited to administration of the compound, pharmaceutical composition or combination.

[00029] The term "restorative treatment" as used herein to describe the present invention, means that the compound, pharmaceutical composition or combination is administered to a subject to modify the underlying progression or etiology of a condition.

[00030] The term "preventive treatment" as used herein to describe the present invention, means that the compound, pharmaceutical composition or combination is administered to a subject for the purpose of bringing the disease or disorder into complete remission, or that the disorder is undetectable after such treatment.

[00031] The term "MIC" as used herein, means the minimum inhibitory concentration (MIC) is the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation.

[00032] The term "compounds of the invention" or "a compound of the invention" as used herein unless otherwise specified, means a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof.

[00033] Non-limiting examples of the above compounds according to the first aspect will now be disclosed.

[00034] In one aspect, there is rovided a compound of formula (I) :


or a pharmaceutically acceptable salt or solvate thereof;

wherein Li is -(CH2)m-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein m is selected from 1 to 5;

wherein Ri and R2 are independently selected from H or CH3, or

Ri is selected from H or H3, and R2 is


wherein L2 is -(CEk , C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein n is selected from 1 to 5;

wherein R3-R8 are independently H, CI, I, Br or F;

wherein at least one of R3-R8 is CI, I, Br or F;

wherein R9 is

wherein L3 is -(CH2)0-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein o is selected from 1 to 5;

wherein L4 is -(CH2)P-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein p is selected from 1 to 5;

wherein Rio, Rn and R12 are independently H or -CH3.

[00035] In an embodiment, Li is selected from -(CH2)m-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein m is selected from 1 to 5. In another embodiment, Li is -(CH2)-. In another embodiment, Li is -(CH2CH2)-. In another embodiment, Li is -(CH2CH2CH2)-. In another embodiment, Li is -(CH2CH2CH2CH2)-. In another embodiment, Li is -(CH2CH2CH2CH2CH2)-. In another embodiment, Li is -(CH=CH)-. In another embodiment, Li is -(CH=CHCH2)-. In another embodiment, Li is -(CH2CH=CH)-. In another embodiment, Li is -(CH=CHCH2CH2)-. In another embodiment, is -(CH2CH=CHCH2)-. In another embodiment, is -(CH2CH2CH=CH)-. In another embodiment, Li is -(CH=CHCH2CH2CH2)-. In another embodiment, Li is -(CH2CH=CHCH2CH2)-. In another embodiment, is -(CH2CH2CH=CHCH2)-. In another embodiment, Li is -(CH2CH2CH2CH=CH)-. In another embodiment, Li is -(C≡C)-. In another embodiment, Li is -(C≡CCH2)-. In another embodiment, Li is -(CH2C≡C)-. In another embodiment, Li is -(C≡CCH2CH2)-. In another embodiment, Li is -(CH2C≡CCH2)-. In another embodiment, Li is -(CH2CH2C≡C)-. In another embodiment, Li is -(C≡CCH2CH2CH2)-. In another embodiment, is -(CH2C≡CCH2CH2)-. In another embodiment, Li is -(CH2CH2C≡CCH2)-. In another embodiment, Li is -(CH2CH2CH2C≡C)-.

[00036] In one embodiment, Li is selected from

[00037] In another embodiment Li is selected from


[00038] In an embodiment, Ri and R2 are independently selected from H or CH3. In another embodiment, Ri and R2 are both H. In another embodiment, Ri and R2 are both CH3. In another embodiment, Ri is H and R2 is CH3. In another embodiment, Ri is selected from H or CH3 and R2 is selected from

O

NH,

HN^NHa

wherein L2 is selected from -(CH2)n-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein n is selected from 1 to 5. In another embodiment, L2 is -(CH2)-. In another embodiment, L2 is -(CH2CH2)-. In another embodiment, L2 is -(CH2CH2CH2)-. In another embodiment, L2 is -(CH2CH2CH2CH2)-. In another embodiment, L2 is -(CH2CH2CH2CH2CH2)-. In another embodiment, L2 is -(CH=CH)-. In another embodiment, L2 is -(CH=CHCH2)-. In another embodiment, L2 is -(CH2CH=CH)-. In another embodiment, L2 is -(CH=CHCH2CH2)-. In another embodiment, L2 is -(CH2CH=CHCH2)-. In another embodiment, L2 is -(CH2CH2CH=CH)-. In another embodiment, L2 is -(CH=CHCH2CH2CH2)-. In another embodiment, L2 is -(CH2CH=CHCH2CH2)-. In another embodiment, L2 is -(CH2CH2CH=CHCH2)-. In another embodiment, L2 is -(CH2CH2CH2CH=CH)-. In another embodiment, L2 is -(C≡C)-. In another embodiment, L2 is -(C≡CCH2)-. In another embodiment, L2 is -(CH2C≡C)-. In another embodiment, L2 is -(C≡CCH2CH2)-. In another embodiment, L2 is -(CH2C≡CCH2)-. In another embodiment, L2 is -(CH2CH2C≡C)-. In another embodiment, L2 is -(C≡CCH2CH2CH2)-. In another embodiment, is -(CH2C≡CCH2CH2)-. In another embodiment, L2 is -(CH2CH2C≡CCH2)-. In another embodiment, L2 is -(CH2CH2CH2C≡C)-. In another embodiment, Ri is selected from H or CH3 and R2 is selected from

[00039] In another em lected from


[00040] In another embodiment, Ri is selected from H or CH3 and R2 is selected from

[00041] In an embodiment, R3-R8 are independently selected from H, CI, I, Br or F; wherein at least one of R3-R8 is CI, I, Br or F. In another embodiment, R3 is selected from CI, I, Br, or F. In another embodiment, R4 is selected from CI, I, Br, or F. In another embodiment, R5 is selected from CI, I, Br, or F. In another embodiment, R6 is selected from CI, I, Br, or F. In another embodiment, R7 is selected from CI, I, Br, or F. In another embodiment, R8 is selected from CI, I, Br, or F.

[00042] In one embodiment, R3 and R4 are independently selected from CI, I, Br, or F. In another embodiment, R3 and R5 are independently selected from CI, I, Br, or F. In another embodiment, R6 and R7 are independently selected from CI, I, Br, or F. In another embodiment, R6 and R8 are independently selected from CI, I, Br, or F. In another embodiment, R3 and R6 are independently selected from CI, I, Br, or F. In another embodiment, R3 and R7 are independently selected from CI, I, Br, or F. In another embodiment, R4 and R6 are independently selected from CI, I, Br, or F. In another embodiment, R4 and R7 are independently selected from CI, I, Br, or F.

[00043] In an embodiment, R3 is CI or Br. In another embodiment, R4 is CI or Br. In another embodiment, R5 is CI or Br. In another embodiment, R6 is CI or Br. In another embodiment, R7 is CI or Br.

[00044] In one embodiment, R3 and R4 are independently selected from CI or Br. In another embodiment, R3 and R5 are independently selected from CI or Br. In another embodiment, R6 and R7 are independently selected from CI or Br. In another embodiment, R6 and R8 are independently selected from CI or Br. In another embodiment, R3 and R6 are independently selected from CI or Br. In another embodiment, R4 and R7 are independently selected from CI or Br. In another embodiment, R3 and R7 are independently selected from CI or Br. In another embodiment, R4 and R6 are independently selected from CI or Br.

[00045] In one embodiment, R3 and R4 are each a CI. In another embodiment, R3 and R5 are each a CI. In another embodiment, R6 and R7 are each a CI. In another embodiment, R6 and R8 are each a CI. In another embodiment, R3 and R6 each a CI. In another embodiment,

R4 and R7 are each a CI. In another embodiment, R3 and R7 are each a CI. In another embodiment, R4 and R6 are each a CI.

NH2

[00046] In an embodiment, R9 is selected from · . In another embodiment, R9 is

selected from

wherein L3 is selected from -(CH2)0-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein o is selected from 1 to 5, wherein R12 is selected from H or CH3. In another embodiment, L3 is -(C¾)-. In another embodiment, L3 is -(CH2CH2)-. In another embodiment, L3 is -(CH2CH2CH2)-. In another embodiment, L3 is -(CH2CH2CH2CH2)-. In another embodiment, L3 is -(CH2CH2CH2CH2CH2)-. In another embodiment, L3 is -(CH=CH)-. In another embodiment, L3 is -(CH=CHCH2)-. In another embodiment, L3 is -(CH2CH=CH)-. In another embodiment, L3 is -(CH=CHCH2CH2)-. In another embodiment, L3 is -(CH2CH=CHCH2)-. In another embodiment, L3 is -(CH2CH2CH=CH)-. In another embodiment, L3 is -(CH=CHCH2CH2CH2)-. In another embodiment, L3 is -(CH2CH=CHCH2CH2)-. In another embodiment, L3 is -(CH2CH2CH=CHCH2)-. In another embodiment, L3 is -(CH2CH2CH2CH=CH)-. In another embodiment, L3 is -(C≡C)-. In another embodiment, L3 is -(C≡CCH2)-. In another embodiment, L3 is -(CH2C≡C)-. In another embodiment, L3 is -(C≡CCH2CH2)-. In another embodiment, L3 is -(CH2C≡CCH2)-. In another embodiment, L3 is -(CH2CH2C≡C)-. In another embodiment, L3 is -(C≡CCH2CH2CH2)-. In another embodiment, L3 is -(CH2C≡CCH2CH2)-. In another embodiment, L3 is -(CH2CH2C≡CCH2)-. In another embodiment, L3 is -(CH2CH2CH2C≡C)-.

[00047] In another embodiment, R9 is selected from


wherein R12 is selected from H or C¾. In another embodiment, R9 is selected from

[00049] In another embodiment, R9 is selected


, wherein R12 is selected from H or CH3.

[00050] In another embodiment, R9 is selected from


wherein R12 is selected from H or CH3.

NH

^NH

[00051] In another embodiment, R9 is selected from l"IN N H2

wherein L4 is selected from -(CH2)P-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein p is selected from 1 to 5. In another embodiment, L4 is -(CH2)-. In another embodiment, L4 is -(CH2CH2)-. In another embodiment, L4 is -(CH2CH2CH2)-. In another embodiment, L4 is -(CH2CH2CH2CH2)-. In another embodiment, L4 is -(CH2CH2CH2CH2CH2)-. In another embodiment, L4 is -(CH=CH)-. In another embodiment, L4 is -(CH=CHCH2)-. In another embodiment, L4 is -(CH2CH=CH)-. In another embodiment, L4 is -(CH=CHCH2CH2)-. In another embodiment, L4 is -(CH2CH=CHCH2)-. In another embodiment, L4 is -(CH2CH2CH=CH)-. In another embodiment, L4 is -(CH=CHCH2CH2CH2)-. In another embodiment, L4 is -(CH2CH=CHCH2CH2)-. In another embodiment, L4 is -(CH2CH2CH=CHCH2)-. In another embodiment, L4 is -(CH2CH2CH2CH=CH)-. In another embodiment, L4 is -(C≡C)-. In another embodiment, L4 is -(C≡CCH2)-. In another embodiment, L4 is -(CH2C≡C)-. In another embodiment, L4 is -(C≡CCH2CH2)-. In another embodiment, L4 is -(CH2C≡CCH2)-. In another embodiment, L4 is -(CH2CH2C≡C)-. In another embodiment, L4 is -(C≡CCH2CH2CH2)-. In another embodiment, L4 is -(CH2C≡CCH2CH2)-. In another embodiment, L4 is -(CH2CH2C≡CCH2)-. In another embodiment, L4 is -(CH2CH2CH2C≡C)-. In another embodiment, R9 is selected from


[00052] In another embodiment, R9 is selected from


[00053] In an embodiment, Rio and Rn are H. In another embodiment, Rio is CH3 and Rn is H. In another embodiment, Rio is H and Rn is CH3. In an embodiment, Rio and Rn are CH3.

[00054] In an embodiment, Ri and R2 are H; Li is-(CH2)m-, wherein m is selected from 1 to 5; wherein R3-R8 are independently H, CI, I, Br or F; wherein at least one of R3-R8 is CI, I, Br

or F; R9 is
wherem L3 [s -(CH2)0-, wherein o is selected from 1 to 5; and

R10-R12 are H.

NH2

L2

NH

[00055] In an embodiment, Ri is H, R2 is HN NH2 , wherein L2 is -(CH2)n-, and wherein n is selected from 1 to 5; Li is-(CH2)m-, wherein m is selected from 1 to 5; wherein R3-R8 are independently H, CI, I, Br or F; wherein at least one of R3-R8 is CI, I, Br or F; R9 is


wherein L3 is -(CH2)0-, wherein o is selected from 1 to 5; and R10-R12 are H.

[00056] In an embodiment, Ri and R2 are H; Li is-(CH2)m-, wherein m is selected from 1 to

5; R4 and R7 are CI or Br; R3, R5, R6, and R8 are H; R9 is
2 . wherein L3 (CH2)0-, wherein o is selected from 1 to 5; and R10-R12 are H.

[00057] In an embodiment, Ri is H, R2 is
H2 , wherein L2 is -(CH2)n-, and wherein n is selected from 1 to 5; Li is-(CH2)m-, wherein m is selected from 1 to 5; R4 and R7

are CI or Br; R3, R5, R6, and R8 are H; R9 is
; wherein L3 is -(CH2)0-, wherein o is selected from 1 to 5; and R10-R12 are H.

[00058] In an embodiment, there is provided a compound of formula (I):


or a pharmaceutically acceptable salt or solvate thereof;

wherein Li, L2, L3, L4, Ri, R2, R9, Rio, R11 and Ri2 are as disclosed herein;

wherein R3, R5, R6 and R8 are H; and

wherein R4 and R7 are independently CI, I, Br or F.

[00059] In an embodiment there is provided a compound of formula (I):


or a pharmaceutically acceptable salt or solvate thereof;

wherein Li, L2, L3, L4, Ri, R2, R9, Rio, R11 and Ri2 are as disclosed herein;

wherein R3, R5, R6 and R8 are H; and

wherein R4 and R7 are independently CI.

[00060] In one aspect, there is provided a rocess for making compounds of formula (I):


or a pharmaceutically acceptable salt or solvate thereof;

wherein Li is -(CH2)m-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein m is selected from 1 to 5;

wherein Ri and R2 are independently selected from H or CH3, or

Ri is selected from H or CH3 and R2

wherein L2 is -(CH2)n-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein n is selected from 1 to 5;

wherein R3-R8 are independently H, CI, I, Br or F;

wherein at least one of R -R8 is CI, I, Br or F;

wherein R9 is

wherein L3 is -(CH2)0-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein o is selected from 1 to 5;

wherein L4 is -(CH2)P-, C2-C5 alkenylene, C2-C5 alkynylene, C3-C6 cycloalkylene, phenylene or benzylene, wherein p is selected from 1 to 5;

wherein Rio, Rn and Ri2 are independently H or -CH3,

by reactin following compounds of formula (II):


wherein R6, R7, Rg, Rio, Rn,Ri2, Li, L3 and L4 have the meaning given above; wherein PGi, PG2 and PG3 can be any protecting group such as t-Boc or Pbf;

in the presence of an amide/peptide coupling reagent with compounds of the formula (III)

wherein R2-R5 are defined as mentioned above,

wherein * denotes an stereogenic carbon;

and deprotection with an acid.

[00061] The person skilled in the art would understand that one Pbf is sufficient to protect the guanidine group while two t-Bocs are required to protect the guanidine group. In certain embodiments, the guanidine group is protected when both PGi are t-Bocs. In certain embodiments, the guanidine group is protected when both PG2 are t-Bocs. In certain embodiments, the guanidine group is protected when both PGi is replaced by a single Pbf. In certain embodiments, the guanidine group is protected when both PG2 is replaced by a single Pbf.

[00062] Compounds of formula (II) can be made by the process wherein

wherein R6, R7, Rg, Rio, Rn,Ri2, Li, L3 and L4 have the meaning given above; wherein PGi, PG2 and PG3 can be any protecting group such as t-Boc or Pbf;

by reacting following compounds of formula (I


wherein R6, R7, Rg, R11, R12, L3 and L4 have the meaning given above; wherein PG4 and PG5 can be any protecting group such as t-Boc or Pbf;

in the presence of an amide/peptide coupling reagent with compounds of the formula (V)


wherein Rio and Li are defined as mentioned above; wherein PG6 can be any protecting group such as t-Boc or Pbf;

wherein * denotes an stereogenic carbon;

and deprotection with an acid.

In certain embodiments, the guanidine group is protected when both PG5 are t-Boc. In certain embodiments, the guanidine group is protected when both PG6 are t-Boc. In certain embodiments, the guanidine group is protected when both PG5 is replaced by a single Pbf. In certain embodiments, the guanidine group is protected when both PG6 is replaced by a single Pbf.

[00063] Compounds of formula (IV) can be made by the process wherein


wherein R6, R7, R8, R11, R12, L3 and L4 have the meaning given above; wherein PG4 and PG5 can be any protecting group such as t-Boc or Pbf;

by reacting following compounds of formula (VI):


wherein R12, L3 and L4 have the meaning given above; wherein PG7 and PG8 can be any protecting group such as t-Boc or Pbf;

in the presence of an amide/peptide coupling reagent with compounds of the formula (VII)


wherein R6i R7, R8 and Rn have the meaning given above;

wherein * denotes an stereogenic carbon;

and deprotection with an acid.

In certain embodiments, the guanidine group is protected when both PG8 are t-Boc. In certain embodiments, the guanidine group is protected when both PG8 is replaced by a single Pbf.

[00064] Compounds of formula (VIb) and (Vic) can be made by reacting following compounds of formula (VIII):

(PG9)

(Vlllb)


(VI lie)

wherein R12, L3 and L4 have the meaning given above; wherein PG9 can be any protecting group such as t-Boc or Pbf;

with N,N'-di-Boc-S-methylisothiourea.

[00065] Compounds of formula (Vllb) can be obtained as known from the chemical literature.

[00066] The person skilled in the art will understand that compounds of formula (I) shown below:

Li Rii

NH

NH NH2

has at least 3 stereogenic carbon centers as denoted by *. The person skilled in the art will understand that more than 3 stereogenic carbon centers may exist, depending on what R2 and R9 are.

[00067] The present invention encompasses all stereoisomers available of compounds of formula (I). In an embodiment, compounds of formula (I) can be produced by L-enantiomers. In another embodiment, compounds of formula (I) can be produced by L and D-enantiomers. In another embodiment, compounds of formula (I) can be produced by D-enantiomers. Without wishing to be bound to theory, it is believed that peptides made from a combination of L and D-enantiomers can lead to an increase in peptide metabolic stability due to higher resistance against proteolytic degradation by human proteases found in skin, blood, body fluids and tissues, as well as bacterial proteases. When only D-enantiomers are used, it has been observed that this leads to a further increase in peptide's plasma stability.

[00068] In certain embodiments, it has been observed that when D-enantiomers are used, there is an improved bioactivity relative to the L-enantiomers.

[00069] A skilled person would also understand that the natural or unnatural amino acids of the compounds of the present invention may be substituted with natural or unnatural β-homo amino acids while retaining their bioactivity.

[00070] In one embodiment, the compounds of the present invention have improved plasma stability. The compounds may also have improved metabolic stability. The compounds may also have improved pharmacokinetic properties.

[00071] The process for making the compounds of formula (I) is described now in more detail.

[00072] In a first reaction step known and commercially available diamines of the formula (VIII) can be reacted with N,N'-di-Boc-S-methylisothiourea in the presence of a base. This reagent is commercially available from Sigma-Aldrich (Merck). Bases can be customary acid acceptors such as tertiary amines, preferably Ν,Ν-disopropylethylamine. Suitable solvents include inert organic solvents such as hydrocarbons, preferably methylene dichloride (dichloromethane) .

[00073] The reaction temperatures in this process step can be varied in a relatively wide range. In general the process is carried out at temperatures of 0 to 100°C, preferably 15 to 60 °C, most preferably at room temperature.

[00074] When carrying out this process step the starting materials of formula (VIII) and the reagent are generally each employed in approximately equal amount. It may be beneficial to use the diamine of formula (VIII) in excess to the reagent.

[00075] Work up can be done by customary separation methods, preferably flash chromatography and evaporation of the solvents.

[00076] In a second reaction step the obtained compounds of the formula (VI) can be reacted with a compound of the formula (VII). Compounds of the formula (VII) are known or can be prepared according to known methods. For instance one of such compounds is commercially available from Merck Millipore and GL Biochem China, Anaspec, Bachem, Chempep, Iris Biotech, Polypeptides or Sigma- Aldrich (Merck) as "Fmoc-4-phenyl-Phe-OH".

[00077] The amide/peptide coupling reagent can be customary coupling reagents such as 2 -(lH-Benzotriazole-l-yl)-l,l,3,3-tetramethyluronium hexafluorophosphate (HBTU). Other suitable coupling reagents include Ν,Ν'-Dicyclohexylcarbodiimide (DCC), (Ν,Ν'-Diisopropylcarbodiimide (DIC), (l-[Bis(dimethylamino)methylene]-lH-l,2,3-triazolo[4,5-bjpyridinium 3-oxid hexafluorophosphate (HATU), 2-(6-Chloro-lH-benzotriazole-l-yl)-l,l,3, 3-tetramethylaminium hexafluorophosphate (HCTU), benzotriazol-l-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBop), 6-Chloro-benzotriazole-l-yloxy-tris-pyrrolidinophosphonium hexafluorophosphate (Pyclock), Ethyl 2-Cyano-2-(hydroxyimino) acetate (Oxyma), N-(Benzenesulfonyl)-L-prolyl-L-0-(l-pyrrolidinylcarbonyl)tyrosine sodium salt (BOP), N,N'-bis(2-oxo-3-oxazolidinyl)-phosphinic chloride (BOP-C1), Ι,Γ-carbonyldiimidazole (CDI), l-Cyano-2-ethoxy-2-oxoethylidenaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), 3-(Diethoxyphosphoryloxy)-l,2,3-benzotriazin-4(3H)-one (DEPBT), l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDC), [(7-azabenzotriazol-l-yl)oxy]tris-(pyrrolidino)phosphonium hexafluorophosphate (PyAOP), [Ethyl cyano(hydroxyimino)acetato-02]tri-l-pyrrolidinylphosphonium hexafluorophosphate (PyOxim), 0-(7-azabenzotriazol- 1 -yl)- 1,1,3,3 -tetramethyluroniumtetrafluoroborate (TATU), 0-benzotriazol-l-yl-l,l,3,3-tetramethyluronium tetrafluoroborate (TBTU), O-[cyano(ethoxycarbonyl)methyleneamino]-N,N,N,N'-tetramethyluronium tetrafluoroborate

(TOTU), or N,N,N',N'-Tetramethyl-0-(N-succinimidyl)uronium tetrafluoroborate (TSTU). Preferably these coupling reagents are used in the presence of a base such as for instance a tertiary amine, preferably N, N-Diisopropylamine. Anti-racemization additives can also be added such as l-hydroxy-7-azabenzotriazole (HO At) and 1-hydroxybenzotriazole (HOBt).

[00078] The reaction temperatures in this process step can be varied in a relatively wide range. In general the process is carried out at temperatures of 0 to 100 °C, preferably 15 to 60 °C, most preferably at room temperature.

[00079] When carrying out this process step the starting materials of formula (VI) and the compound of formula (VII) are generally each employed in approximately equal amount. It may be beneficial to use the compound of formula (VII) in small excess.

[00080] Work up can be done by customary separation methods, preferably by washing steps and an evaporation of the solvent. Dissolution and further post -reaction with a base, such as 1,8-Diazabicyclo [5.4.0] undec-7-ene (DBU), at room temperature and flash chromatography is possible.

[00081] In a third reaction step the obtained compounds of the formula (IV) can be reacted with a compound of the formula (V). Compounds of the formula (V) are known or can be prepared according to known methods. For instance one of such compounds is commercially available from Merck Millipore or GL Biochem, Anaspec, Bachem, Chempep, Iris Biotech, Polypeptides or Sigma-Aldrich (Merck) as "Fmoc-Arg(Pbf)-OH" or Fmoc-Arg(Boc)-2-OH.

[00082] The amide/peptide coupling reagent can be customary coupling reagents such as 2-(lH-Benzotriazole-l-yl)-l,l,3,3-tetramethyluronium hexafluorophosphate (HBTU). Other suitable coupling reagents include Ν,Ν'-Dicyclohexylcarbodiimide (DCC) , (Ν,Ν'-Diisopropylcarbodiimide (DIC), (l-[Bis(dimethylamino)methylene]-lH-l,2,3-triazolo [4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU), 2-(6-Chloro-lH-benzotriazole-l-yl)-1,1,3,3-tetramethylaminium hexafluorophosphate (HCTU), benzotriazol-l-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBop), 6-Chloro-benzotriazole-l-yloxy-tris-pyrrolidinophosphonium hexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino) acetate (Oxyma). Preferably these coupling reagents are used in the presence of a base such as for instance a tertiary amine, preferably N,N-Diisopropylamine.

[00083] Suitable solvents include inert organic solvents such as dimethylformamide.

[00084] The reaction temperatures in this process step can be varied in a relatively wide range. In general the process is carried out at temperatures of 0 to 100 °C, preferably 15 to 60 °C, most preferably at room temperature.

[00085] When carrying out this process step the starting materials of formula (IV) and the compound of formula (V) are generally each employed in approximately equal amount. It may be beneficial to use the compound of formula (V) in excess.

[00086] Work up can be done by customary separation methods, preferably by washing steps and an evaporation of the solvent. Dissolution and further post reaction with a base, such as 1,8-Diazabicyclo [5.4.0] undec-7-ene (DBU) or piperidine, at room temperature and flash chromatography is possible.

[00087] In a fourth reaction step the obtained compounds of the formula (II) can be reacted with a compound of the formula (III). Compounds of the formula (III) are known or can be prepared according to known methods. For instance one of such compounds is commercially available from Merck Millipore or GL Biochem, Anaspec, Bachem, Chempep, Iris Biotech, Polypeptides or Sigma- Aldrich (Merck) as "Fmoc-4-phenyl-Phe-OH" or "Fmoc-Bip-OH". It can also be bought from Creosalus Advanced ChemTech.

[00088] The amide/peptide coupling reagent can be customary coupling reagents such as 2-(lH-Benzotriazole-l-yl)-l,l,3,3-tetramethyluronium hexafluorophosphate (HBTU). Other suitable coupling reagents include Ν,Ν'-Dicyclohexylcarbodiimide (DCC), [Ν,Ν'-Diisopropylcarbodiimide (DIC), (l-[Bis(dimethylamino)methylene]-lH-l,2,3-triazolo [4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU), 2-(6-Chloro-lH-benzotriazole-l-yl)-1,1,3,3-tetramethylaminium hexafluorophosphate (HCTU), benzotriazol-l-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBop), 6-Chloro-benzotriazole-l-yloxy-tris-pyrrolidinophosphonium hexafluorophosphate (Pyclock), Ethyl 2-Cyano-2-(hydroxyimino) acetate (Oxyma), N-(Benzenesulfonyl)-L-prolyl-L-0-(l-pyrrolidinylcarbonyl)tyrosine sodium salt (BOP), N,N'-bis(2-oxo-3-oxazolidinyl)-phosphinic chloride (BOP-C1), Ι,Γ-carbonyldiimidazole (CDI), l-Cyano-2-ethoxy-2-oxoethylidenaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), 3-(Diethoxyphosphoryloxy)-l,2,3-benzotriazin-4(3H)-one (DEPBT), l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDC), [(7-azabenzotriazol-l-yl)oxy]tris-(pyrrolidino)phosphonium hexafluorophosphate (PyAOP), [Ethyl cyano(hydroxyimino)acetato-02]tri-l-pyrrolidinylphosphonium hexafluorophosphate (PyOxim), 0-(7-azabenzotriazol- 1 -yl)- 1,1,3,3 -tetramethyluroniumtetrafluoroborate (TATU), 0-benzotriazol-l-yl-l,l,3,3-tetramethyluronium tetrafluoroborate (TBTU), O-[cyano(ethoxycarbonyl)methyleneamino]-N,N,N,N'-tetramethyluronium tetrafluoroborate (TOTU), or N,N,N',N'-Tetramethyl-0-(N-succinimidyl)uronium tetrafluoroborate (TSTU). Preferably these coupling reagents are used in the presence of a base such as for instance a tertiary amine, preferably Ν,Ν-Diisopropylamine. Anti-racemization additives can also be added such as l-hydroxy-7-azabenzotriazole (HO At) and 1-hydroxybenzotriazole (HOBt).

[00089] Suitable solvents include inert organic solvents such as dimethylformamide.

[00090] The reaction temperatures in this process step can be varied in a relatively wide range. In general the process is carried out at temperatures of 0 to 100°C, preferably 15 to 60 °C, most preferably at room temperature.

[00091] When carrying out this process step the starting materials of formula (IV) and the compound of formula (V) are generally each employed in approximately equal amount. It may be beneficial to use the compound of formula (V) in excess.

[00092] Work up can be done by customary separation methods, preferably by washing steps and an evaporation of the solvent. Dissolution and further post-reaction with a base, such as diazabicycloundecene (DBU) or piperidine, at room temperature and flash chromatography is possible.

[00093] The compounds of the formula (I) can be obtained from their precursors by reaction with a strong organic acid such as trifluoroacetic acid. Such organic acids must be able to remove the Pbf and Boc moieties.

[00094] The reaction temperatures in this process step can be varied in a relatively wide range. In general the process is carried out at temperatures of 0 to 100 °C, preferably 15 to 60 °C, most preferably at room temperature.

[00095] Work up is done by customary separation methods, preferably by evaporation of the solvent, re-dissolution, chromatography and HPLC.

[00096] Some of the comparators can be prepared according to WO2015112093, the entire content of which is incorporated herein by reference.

[00097] Other compounds disclosed herein also can be synthesized analogous to the compounds of Formula (I) or can be synthesized utilizing known methodologies disclosed in texts well known to those skilled in the art such as Amino acids, Peptides and Proteins in Organic Chemistry, Ed. A. B. Hughes, vol. 4.; Wiley-VCH, Germany, 2011, or Coin I, Beyermann M, Bienert M. Solid-phase peptide synthesis: from standard procedures to the synthesis of difficult sequences. Nat Protoc. 2007; 2(12):3247-56.

[00098] The compounds disclosed herein may be made by solid-phase peptide synthesis methods as described above. A skilled person would also be able to make the compounds using solution-phase synthesis methods that are known in the art.

[00099] In one aspect, there is provided a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutically acceptable excipient.

[000100] The compounds of the invention may exist in a continuum of solid states ranging from fully amorphous to fully crystalline. Compounds of the invention may also exist in both unsolvated and solvated forms. The term "solvate" is used herein to describe a molecular complex comprising the compound of the invention and a stoichiometric amount of one or more pharmaceutically acceptable solvent molecules. The term "hydrate" is employed when said solvent is water. A pharmaceutically acceptable acid addition salt may be readily prepared by using a desired acid as appropriate. Other non-pharmaceutically acceptable acid addition salts may be used, for example in the isolation of compounds of the invention, and are included within the scope of this invention. Typically an acid addition salt can be formed by reaction of a compound of formula (I) with a suitable inorganic or organic acid (such as acetic, benzoic, citric, hydrobromic, hydrochloric, formic, fumaric, maleic, methanesulfonic, naphthalenesulfonic, nitric, oxalic, p-toluenesulfonic, phosphoric, succinic, sulfuric, tartaric, or trifluoroacetic acid), optionally in a suitable solvent such as an organic solvent, to give the salt which is usually isolated for example by crystallisation and filtration. Thus, a pharmaceutically acceptable acid addition salt of a compound of formula (I) can be for example a acetate, benzoate, citrate, hydrobromide, hydrochloride, formate, fumarate, maleate, methanesulfonate, naphthalenesulfonate, nitrate, oxalate, p-toluenesulfonate phosphate, succinate, sulfate, tartrate, or trifluoroacetate salt.

[000101] The invention includes within its scope all possible stoichiometric and non-stoichiometric forms of the salts of the compounds of formula (I) and is not limited to those specifically mentioned.

[000102] Compounds of the present invention can form addition salts, reaction of the amino substituent of formula (I) with a suitable acid. Pharmaceutically acceptable salts of the compounds of formula (I) include the acid salts addition of them.

[000103] Without wanting to be bound by theory it is believed that the hydrophobic nature of the halogens at R3-R8 increases the affinity of the peptide for the bacteria's membrane and thus result in an improved membrane disrupting activity.

[000104] In some embodiments, the compounds of the invention show a particular surprising high activity against the bacteria selected from Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Propionibacterium acnes. In some embodiments,

the compounds of the invention show a particular surprising high activity against Gram-positive bacteria.

[000105] The compounds of the present invention can have potent bactericidal activities against strains that are resistant to penicillin-type antibiotics, such as Methicillin, and even Vancomycin. The compounds can also have potent bactericidal activities against strains that are resistant to Mupirocin, Linezolid, Retapamulin or Tigecycline. The compounds can be effective in combating these bacteria at surprisingly low micro molar levels such as 6.25 μΜ or less measured as MIC values (including low MIC values of about 1 μΜ).

[000106] In certain embodiments, the compounds are bactericidal against Gram-positive bacteria, including Staphylococcus aureus strains ATCC-BAA-1556, ATCC-BAA-1708, ATCC-BAA-1750 (USA200), ATCC-BAA-1681 (USA100) ATCC-BAA-1756 (USA300), ATCC-BAA-1707 (USA400), ATCC-BAA-2762 (EMRSA15, ST22), ATCC-BAA-1754 (ST45), ATCC-33592 (ST239), ATCC-700699 (VISA), ATTC-29213, RN 4220, ATCC-BAA-44, ATCC-BAA-1720, ATCC-BAA-2094, ATCC-33591 and ATCC-BAA-1680.

[000107] In one embodiment, the compounds are bactericidal against Staphylococcus aureus (SA) strains. In one embodiment, the compounds are bactericidal against Mupirocin-resistant MRS A strains and Mupirocin-susceptible MRS A strains. The Mupirocin-resistant MRS A strains include ATCC-BAA-1556, ATCC-BAA-1708 and ATCC-BAA-1750 (USA200). The Mupirocin-susceptible strains include ATCC-BAA-1681 (USA100) ATCC-BAA-1756 (USA300), ATCC-BAA-1707 (USA400), ATCC-BAA-2762 (EMRSA15, ST22), ATCC-BAA-1754 (ST45), ATCC-33592 (ST239) and ATCC-700699 (VISA).

[000108] In some embodiments, the compounds of the formula (I) or a pharmaceutically acceptable salt or solvate thereof are particularly useful for the treatment of diseases, disorders or conditions caused by bacteria.

[000109] In one embodiment, the compounds of formula (I) are extremely effective as antibacterial, advantageously showing potent bactericidal activities against MRSA.

[000110] In one embodiment, there is provided a method of treating a disease, disorder or condition, wherein the disease, disorder or condition is a bacterial infection, such as for instance a skin infection (e.g. boils, cuts, cellulitis, surgical wounds, impetigo), a blood infection, a respiratory disease (e.g. sinusitis, pneumonia), nasal decolonization, food poisoning or any other life-threatening systemic disease, in a subject in need of such treatment, comprising administering to said subject a compound of the formula (I) or a pharmaceutically acceptable salt or solvate thereof.

[000111] In one embodiment, there is provided a method of preventing a disease, disorder or condition, wherein the disease, disorder or condition is a bacterial infection, such as for instance a skin infection (e.g. boils, cuts, cellulitis, surgical wounds, impetigo), a blood infection, a respiratory disease (e.g. sinusitis, pneumonia), nasal decolonization, food poisoning or any other life-threatening systemic disease, in a subject in need of such treatment, comprising administering to said subject a compound of the formula (I) or a pharmaceutically acceptable salt or solvate thereof.

[000112] In one embodiment, there is provided a method of treating or preventing an acne condition, wherein the acne condition is a bacterial infection, in a subject in need of such treatment, comprising administering to said subject a compound of the formula (I) or a pharmaceutically acceptable salt or solvate thereof. In one embodiment, the bacterial infection is caused by Propionibacterium acnes.

[000113] In an embodiment, there is provided a method of disinfecting a surface against bacterial contamination by applying to said surface a compound of the formula (I) or an acceptable salt or solvate thereof. In another embodiment, there is provided a method of disinfecting a surface against Mupirocin-resistant bacteria contamination by applying to said surface a compound of the formula (I) or an acceptable salt or solvate thereof. The Mupirocin-resistant bacteria may be Mupirocin-resistant Staphylococcus aureus. In one embodiment, the method of disinfecting a surface is used for nasal decolonization. This may be applied topically to a subject prior to, for example, a surgery.

[000114] In one aspect, there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof in the manufacture of a medicament for the treatment of a disease, disorder or condition selected from any bacterial infection, such as for instance a skin infection (e.g. boils, cuts, cellulitis, surgical wounds, impetigo), a blood infection, a respiratory disease (e.g. sinusitis, pneumonia), nasal decolonization, food poisoning or any other life-threatening systemic disease.

[000115] In one embodiment, there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof in the manufacture of a medicament for the treatment of an acne condition. In one embodiment, the acne condition is due to a bacterial infection. The bacterial infection may be caused by Propionibacterium acnes.

[000116] In one aspect, there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof for use in treating a bacterial infection. [000117] In one aspect, there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof in the manufacture of a medicament for the treatment of a bacterially caused disease, disorder or condition.

[000118] In certain embodiments, the medicament can be for treatment or for prophylactic use.

[000119] In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is caused by a Gram-positive bacteria.

[000120] In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae or Propionibacterium acnes. In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by Staphylococcus aureus. In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by Methicillin-resistant Staphylococcus aureus. In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by a Methicillin-resistant Staphylococcus aureus strain that is resistant to Mupirocin. In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by a Methicillin-resistant Staphylococcus aureus strain that is resistant to Linezolid, Retapamulin or Tigecycline. In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by a Staphylococcus aureus strain that is resistant to Linezolid, Retapamulin or Tigecycline. In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is due to or caused by Propionibacterium acnes.

[000121] In one embodiment, the bacterial infection or bacterially caused disease, disorder or condition is caused by bacteria that have gained a resistance against the penicillin-type antibiotics, Vancomycin, Linezolid, Retapamulin, Tigecycline or Mupirocin. In one embodiment, the bacteria have gained a resistance to Mupirocin. In one embodiment, the penicillin-type antibiotic is Methicillin.

[000122] For administration to human patients, the total daily dose of a compound of the invention can be in the range of 0.5 to 2 grams, but is not limited to that range depending on the mode of administration. The total daily dose may be administered in single or divided doses, and may, at the physicians discretion, fall outside of this typical range.

[000123] Administration can be oral or parenteral (such as topical and ocular) or otherwise. In the pharmaceutical composition of the compounds of the invention excipients can be used. The term "excipient" encompasses diluents, carriers and adjuvants.

[000124] If the compounds are administered in tablets such as for example disclosed in Tablets, Vol. 1, by H. Liberman and L. Lachman (Marcel Dekker, New York, 1980).

[000125] The compounds of the invention may also be administered directly into the blood stream, into muscle or into an internal organ. Suitable means for parenteral administration include intravenous, intraarterial, intraperitoneal, intrathecal, intraventricular, intraureathral, intrasternal, intracranial, intramuscular, ocular and subcutaneous. Suitable devices for parenteral administration include needle injectors, needle free injectors and infusion techniques.

[000126] The compounds may also be administered topically to the skin or mucosa, that is, dermally, intranasal (such as a spray) or transdermal. In one embodiment, the compounds of formula (I) are especially useful in such topical applications where they can combat Methicillin-resistant Staphylococcus aureus strains.

[000127] The compounds of the invention may also be administered directly to the eye, nose or ear, typically in the form of drops of micronized suspension or solution in isotonic, pH-adjusted, sterile saline.

[000128] The compounds can also be inhaled to treat infection of the respiratory tract. Typical inhalers and inhalation formulations can be used. The formula (I) provides general definitions of the compounds according to the invention.

Examples

[000129] In the examples described below, unless otherwise indicated, all temperatures in the following description are in degrees Celsius and all parts and percentages are by weight, unless indicated otherwise. Reagents useful for synthesizing compounds may be purchased from commercial suppliers, such as Merck Millipore, GL Biochem China, Creosalus Advanced Chemtech, Anaspec, Bachem, Chempep, Iris Biotech, Polypeptides, Sigma-Aldrich (Merck) and others, and used without further purification, unless otherwise indicated, or obtained or prepared according to techniques known in the art.

[000130] HPLC was conducted on a Shimadzu Prominence system. Mass spectrometry was conducted using a Shimadsu LC-MS system.

[000131] All the NMR experiments for ιΉ (400.13 MHz) and 13C (100.61 MHz) nuclei were performed on a Bruker Ultrashield 400+ NMR spectrometer. NMR spectra are reported in

ppm with reference to an internal tetramethylsilane standard (0.00 ppm for 1 H and 13 C) or solvent peak(s) of CD3OD (3.31 and 49.0 ppm). When peak multiplicities are reported, the following abbreviations are used: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broadened, dd = doublet of doublets, dt = doublet of triplets, bs = broadened singlet. Coupling constants, when given, are reported in hertz.

Example 1: Preparation of Compound 34

1. Swell Rink amide resin (1 mmol scale, 3.57 g, GL Biochem (China), Loading factor:

0.28) in piperidine:DMF (20% v/v) at RT for 1 hour.

2. Filter off excess solvent/reagents and wash resin with DMF (~ 10ml x 2), CH3OH (~ 10ml x 2) followed by DMF (~ 10ml x 2) again.

3. Dissolve Fmoc-D-Arg(Pbf)-OH (2 mmol, 2 eq, 1.3 g, Creosalus Advanced ChemTech), HBTU (2 mmol, 2 eq.), HOAt, DIPEA (2 mmol, 2 eq.) in DMF (20 mL) and allow this mixture to react with the resin with stirring at RT for 1 h.

4. Filter off excess solvent/reagents and wash resin with DMF (~ 10ml x 2), CH3OH (~ 10ml x 2) followed by DMF (~ 10ml x 2) again.

5. Introduce piperidine:DMF (20% v/v) into the resin with stirring at RT for 0.5 h.

6. Filter off excess solvent/reagents and wash resin with DMF (~ 10ml x 2), CH3OH (~ 10ml x 2) followed by DMF (~ 10ml x 2) again.

7. Dissolve N-Fmoc-4-(4-chlorophenyl)-D-phenylalanine (2 mmol, 2 eq, 1.0 g, Amatek Chemical, China), HBTU (2 mmol, 2 eq.), HOAt, DIPEA (2 mmol, 2 eq.) in DMF (20 mL) and allow this mixture to react with the resin with stirring at RT for 1 h.

8. Filter off excess solvent/reagents and wash resin with DMF (~ 10ml x 2), CH3OH (~ 10ml x 2) followed by DMF (~ 10ml x 2) again.

9. Introduce piperidine:DMF (20% v/v) into the resin with stirring at RT for 0.5 h.

10. Filter off excess solvent/reagents and wash resin with DMF (~ 10ml x 2), CH3OH (~ 10ml x 2) followed by DMF (~ 10ml x 2) again.

11. Couple subsequent amino acid using Steps 6 - 10.

12. Wash resin with DMF (~ 10ml x 2), CH3OH (~ 10ml x 2) followed by CH2C12 (~ 10ml x 2).

13. Add trifluoroacetic acid (TFA) (2 mL for 0.1 mmol scale) and deionized water (2 drops, -50 μί). Allow this mixture to react with the resin with stirring and microwave (400W, 60 °C, 20 min).

14. Excess TFA was blown off with a N2 gas stream to yield the crude target as yellow oil. 15. Purify the yellow oil with C18 reverse-phase HPLC (1 niL concentrated HC1 in 2 L H20) to obtain target as a white solid (349 mg, 36.6%). ESI-MS m/z [M+H]+ 844.4; [M+2H]2+÷2 422.7. Electrospray ionization-mass spectrum results is shown in Figure 4. NMR results is shown in Figure 5.

Some of the comparators are made under similar conditions as outlined in Example 1.

Specific Example: Compound 34


[000132] To a solution of A (170 g, 493.9 mmol) in DME (2040 mL) was added B (96.5 g, 617.3 mmol) followed by aq. Na2C03 (2 M, 370.4 mL) and Pd(PPh3)4 (17.1 g, 14.8 mmol). The mixture was stirred at 85 °C for 3 hrs. The reaction mixture was filtered and added EtOAc (3 L) and acidified by 1 M HC1 to pH = 5. The combined organic layer was washed with brine (1 L) and dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The obtained residue was purified by column chromatography on silica gel (100-200 mesh size) using petroleum ether/EtOAc(20: 1-1: 1) as eluent to give C (156 g, 332.0 mmol, 67.2% yield, 80.0% purity) as a white solid. 1H NMR 400 MHz, CDC135 ppm 7.54 -7.76 (m, 1 H) 7.43 - 7.53 (m, 5 H) 7.36 - 7.42 (m, 2 H) 7.23 - 7.30 (m, 2 H) 4.37 - 4.76 (m, 1 H) 2.90 - 3.32 (m, 2 H) 1.27 - 1.47 (m, 9 H) LCMS m/z [+ESI scan] 275.8, 397.8, 772.8.


C D

[000133] A mixture of C (125 g, 332.5 mmol) and HCl/EtOAc (4 M, 1.25 L) was stirred at 25 °C for 0.5 hr. The reaction mixture was filtrated and the resulting solid was dry by evaporating under vacuum to give D (85 g, 245.0 mmol, 73.6% yield, 90.0% purity, HC1) as a white solid. 1H NMR 400 MHz, DMSO-d6 δ ppm 13.83 (br s, 1 H) 8.65 (br s, 3 H) 7.59 -7.73 (m, 4 H) 7.50 (d, = 8.53 Hz, 2 H) 7.40 (br d, = 8.03 Hz, 2 H) 4.17 (br s, 1 H) 3.23 (br d, = 5.52 Hz, 2 H) LCMS m/z [+ESI scan] 276.0.


D E

[000134] To a solution of D (60 g, 192.2 mmol, HC1) in H20 (1200 niL) and acetone (3600 niL) was added Fmoc-OSu (84.3 g, 249.8 mmol) and NaHC03 (82.6 g, 984.1 mmol, 38.2 mL) until pH = 8. The mixture was stirred at 25°C for 16hrs. The resulting mixture was concentrated in vacuo and the aqueous phase was added with 1.0 M HC1 solution till the pH = 4-5, filtrated, the solid was washed with water (1.2 L x 2), filtrated. The solid stirred in acetonitrile (3500 mL), filtrated, the resulting solid was dry by evaporating under vacuum to give E (82.3 g, 155.6 mmol, 80.9% yield, 94.18% purity) as a white solid. 1H NMR 400 MHz, DMSO-d6 δ ppm 7.87 (br d, = 7.53 Hz, 2 H) 7.51 - 7.69 (m, 7 H) 7.48 (d, = 8.53 Hz, 2 H) 7.24 - 7.43 (m, 6 H) 4.08 - 4.26 (m, 4 H) 3.14 (dd, = 13.68, 4.14 Hz, 1 H) 2.92 (dd, / = 13.55, 10.29 Hz, 1 H) LCMS m/z [+ESI scan] 178.8, 275.9, 497.9, 1017.1.


[000135] The peptide was synthesized using standard Fmoc chemistry. 1) Add DMF to the vessel containing MBHA Resin (sub: 0.6 mmol/g, 110.0 mmol, 183.0 g) and swell for 2 hours. 2) Add Fmoc-Rink linker and mix 30 seconds, then add activation buffer, N2 bubbling for about 1 hour. 3) Drain and then DMF wash 30 sec with 3 times. 4) Add 20% piperidine/DMF and mix for 30 min. 5) Drain and then DMF wash 30 sec with 5 times. 6) Add Fmoc-amino acid solution and mix 30 seconds, then add activation buffer, N2 bubbling for about 1 hour. 7) Repeat step 3 to 6 for next amino acid coupling. Note:

# Materials Coupling reagents

1 Fmoc-Rink linker (2.0 eq) HBTU (1.9 eq) and DIEA (4.0 eq)

2 Fmoc-D-Arg(pbf)-OH (2.0 eq) HBTU (1.9 eq) and DIEA (4.0 eq)

(R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3- 3 HATU (1.9 eq) and DIEA (4.0 eq) (4'-chloro-[l,l'-biphenyl]-4-yl)propanoic acid (2.0 eq)

4 Fmoc-D-Arg(pbf)-OH (2.0 eq) HATU (1.9 eq) and DIEA (4.0 eq)

(R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3- 5 HATU (1.9 eq) and DIEA (4.0 eq) (4'-chloro-[l,l'-biphenyl]-4-yl)propanoic acid (2.0 eq)

20% piperidine in DMF was used for Fmoc deprotection for 30 min. The coupling reaction was monitored by ninhydrin test, and the resin was washed with DMF for 5 times.

Peptide Cleavage and Purification: 1) Add cleavage buffer (95%TFA/2.5%Thioanisole/2.5%H20) to the flask containing the side chain protected peptide at room temperature and stir for 3 hours. 2) The peptide is precipitated with cold tert- butyl methyl ether and centrifuged (2 min at 5000 rpm). 3) Tert-butyl methyl ether washes two additional times. 4) Dry the crude peptide under vacuum 2 hours. 5) Purify the crude peptide by Pre_HPLC (A: 0.005 mol/L HCl in H20, B: ACN) to give the final product (51.2 g, 99.33% purity, 55.1% yield). 6) Purification conditions:


LCMS m/z [+ESI scan] 258.1, 422.7, 844.2.

[000136] The examples of the present invention are made under similar conditions as outlined in Example 1. Table 1 shows the ESI-MS (m/z) data for the exemplary compounds.

Table 1: ESI-MS data of compounds

ESI-MS

Compound No.

[M+H]+ [M+2H]2+÷ 2

15 811.0 406.2

16 811.0 406.2

17 844.4 423.1

18 844.0 423.5

19 856.9 428.9

20 856.9 428.4

27 811.0 406.0

28 811.0 406.2

33 844.4 422.8

35 688.3 not detected

39 Not detected 501.0

41 802.4 not detected

42 Not detected 423.1

43 Not detected 422.9

44 Not detected 423.3

45 Not detected 423.8

Example 2: Biological activity measurement

[000137] The MICs of test compounds were determined using the microdilution method from the Clinical and Laboratory Standards Institute (CLSI) guidelines (Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard - ninth edition. Document M07-A9. Vol. 32 No. 2. Wayne, PA: CLSI; 2012). Briefly, bacteria were grown fresh from frozen stock in Mueller Hinton 2 (MH2) agar at 37°C. After an overnight incubation, 5 bacteria colonies were selected to grow in cation-adjusted MH2 broth in a shaking incubator (140 RPM) at 37°C. Cells were grown to an optical density (OD6oo) of 0.15-0.16 determined using a spectrophotometer (Molecular Devices Spectra Max Plus), which corresponds to ~ 1 x 10 CFU/mL. Test compounds were constituted into 4 mM DMSO stock solutions and then subjected to 2-fold serial dilution in a 96-well plate with concentrations ranging from 100 to 0.195 μΜ in duplicates. 50 mL of microbial culture containing ~1 x 106 CFU/mL of microbes in the respective broths was introduced into each well containing 50 μΐ^ of compound solution. After an overnight incubation at 35°C, (220 RPM), OD6oo measurements were conducted using the microplate spectrophotometer. The MIC was defined as the lowest antibiotic or compound concentration (μΜ) required to inhibit bacteria growth.

[000138] The 11th well was used as the growth control well (medium with bacterial inoculums, no antibacterial) while the 12th well was the sterility control well (medium only). Table 2 illustrates a typical sample layout.

Table 2: Typical plate layout for the setup of a 96-well plate for the cell-based assay

[000139] Table 3 shows the structures of examples and comparators and their corresponding minimum inhibitory concentration (MIC) against ATCC-BAA-1556.

[000140] Table 4 compares the minimum inhibitory concentrations of Compounds 33 and 34 against commercial antibacterial compounds Linezolid, Mupirocin, Retapamulin, Vancomycin as well as Compound 2 (which is a comparator) in Mupirocin-resistant and Mupirocin-susceptible MRSA strains. Compounds 33 and 34 are shown to have about 4 fold improvements of bioactivity (in terms of lower MIC values) against Mupirocin-resistant MRSA strains as compared to Compound 2. For example, Compounds 33 and 34 each have a MIC value of 3.125 μΜ against ATCC-BAA-1556 whereas Compound 2 has a MIC value of 12.5 μΜ against the same strain.

[000141] A time -kill assay was performed (Figure 1) and Compound 34 is shown to kill Mupirocin-resistant MRSA (ATCC-BAA-1556) more rapidly as compared to Linezolid, Retapamulin and Vancomycin at 4x MIC.

[000142] Figure 2 shows a bacterial/static determination assay where Compound 34 is shown to have higher bactericidal activity than Linezolid, Retapamulin and Vancomycin against Mupirocin-resistant MRSA (ATCC-BAA-1556) at 4x MIC.

[000143] Figure 3 shows the determination of the minimum bactericidal concentration of Compound 34 using Mupirocin-resistant MRSA at MIC and 2x MIC.

Table 3. Structures and MICs (Mupirocin-resistant MRSA ATCC-BAA-1556)









Comparator 50

Comparator 50

Comparator 100


Comparator >100

Comparator >100

Comparator >100

Example 3.125

Comparator >100

Example 6.25

Example 6.25

Example 6.25

44 Example 6.25

45 Example 6.25


Table 4: MICs (μΜ) of compounds against various MRSA strains


BAA-1556 6.25 > 100 <0.2 0.78 12.5 3.125 3.125

BAA- 1708 6.25 > 100 <0.2 0.78 6.25 1.56 1.56

BAA-1750 6.25 25 <0.2 0.78 6.25 1.56 1.56

(USA200)

BAA-1681 6.25 <0.2 <0.2 1.56 6.25 3.125 3.125

(USA100)

BAA-1756 6.25 <0.2 <0.2 0.78 6.25 3.125 1.56

(USA300)

BAA- 1707 6.25 <0.2 <0.2 0.78 6.25 3.125 3.125

(USA400)

BAA-2762 6.25 <0.2 <0.2 0.78 6.25 3.125 3.125

(EMRSA15,

ST22)

BAA-1754 6.25 < 0.2 < 0.2 0.78 6.25 3.125 3.125

(ST45)

33592 6.25 < 0.2 < 0.2 0.78 6.25 3.125 3.125

(ST239)

700699 3.125 < 0.2 < 0.2 6.25 6.25 3.125 3.125

(VISA)

Example 3: Activity of Compound 34 in anti-infective In Vitro assay

[000144] The antibacterial potency of Compound 34 was measured using the in vitro broth microdilution assay under assay conditions described by the Clinical and Laboratory Standards Institute. In this assay, the Minimum Inhibitory Concentration (MIC) is defined as the lowest concentration of an agent that completely inhibits visible growth in vitro of the microorganism. The test substance was dissolved in 100% DMSO (unless stated below), suspended completely by sonication or vortexing, diluted by 2-fold serial titrations in the same vehicle, for a total of 10 test concentrations (final concentrations: 100, 50, 25, 12.5, 6.25, 3.125, 1.56, 0.78, 0.39, 0.2 μΜ). A 4 μΐ, aliquot of each dilution was added to 196 \J of broth medium seeded with the organism suspension in wells of a 96 well plate (bacterial count: 2 -8 x 105 colony forming units/mL final). The final volume was 200 μL· in each well and the final DMSO concentration was 2 percent. The incubation time is either 1 or 2 days at 36°C. All strains tested underwent aerobic respiration, except for ATCC BAA- 1805 and ATCC 29399. Following incubation, the test plates were visually examined and wells were scored for growth or complete growth inhibition to define the minimum inhibitory concentration. Each test substance was evaluated in duplicate and the results below are the duplicate test values. Vehicle-control and an active reference agent were used as blank and positive controls, respectively. Results are shown in Table 5.

Table 5: Activity of Compound 34 against various ATCC strains

Strain Organism Broth MIC Comparator

Medium (μΜ) Compound MIC (Mg/mL) MIC (μΜ)

ATCC Enterococcus CAMHB II 3.13 Tigecycline 0.063 0.11 51299 faecalis

ATCC Enterococcus CAMHB II 1.56 Tigecycline 0.063 0.11 BAA- faecium

2320

ATCC Staphylococcus CAMHB II 3.13 Vancomycin 1.0 0.69 BAA- aureus

1717

ATCC Staphylococcus CAMHB II 3.13 Vancomycin 1.0 0.69 12228 epidermidis

ATCC Staphylococcus CAMHB II 3.13 Vancomycin 1.0 0.69 19636 aureus

ATCC Propionibacterium RCM 1.56 Vancomycin 0.5 0.35 29399 acnes

Example 4: Activity of Compound 34 in anti-infective In Vitro assay (S. aureus)

The antibacterial potency of Compound 34 was measured using the in vitro broth microdilution assay under assay conditions described by the Clinical and Laboratory Standards Institute. In this assay, the Minimum Inhibitory Concentration (MIC) is defined as the lowest concentration of an agent that completely inhibits visible growth in vitro of the microorganism. The test substance was dissolved in 100% DMSO (unless stated below), suspended completely by sonication or vortexing, diluted by 2-fold serial titrations in the same vehicle, for a total of 11 test concentrations. A 4 μΐ^ aliquot of each dilution was added to 196 μΐ^ of broth medium seeded with the organism suspension in wells of a 96 well plate (bacterial count: 2 -8 x 105 colony forming units/mL final). The final volume was 200 μL· in each well and the final DMSO concentration was 2%. The incubation time is 1 day at 36°C. All strains tested underwent aerobic respiration. Following incubation, the test plates were visually examined and wells were scored for growth or complete growth inhibition to define the minimum inhibitory concentration. Each test substance was evaluated in duplicate and the results below are the duplicate test values. Vehicle-control and an active reference agent were used as blank and positive controls, respectively. Results are shown in Table 6.

Table 6: Activity of Compound 34 against various S. aureus strains

Example 5: Activity of Compound 34 compared to Comparators

[000145] S. aureus (BAA-1556) was from ATCC. Mupirocin (Cat# M2955) was purchased from TCI chemicals (India) Pvt. Ltd., ciprofloxacin (Cat# 17850) and linezolid (Cat# PZ0014) were purchased from Sigma-Aldrich Chemicals Pvt. Ltd, India, Cation adjusted Mueller Hinton broth (CAMHB) and Mueller Hinton Agar (MHA) (Cat# M1657) were from HiMedia Laboratories Pvt. Ltd, India.

[000146] The MIC assay was done based on CLSI guidelines in a microtitre plate format (1, 2). Preparation and dilution of Test Item (TI) stock solutions: A 1280 μg/ml stock of Compound 34 was prepared by dissolving 1.28 mg in 1.0 ml of sterile water to obtain the Master Stock (MS) solution. The MS solution was diluted 2-fold to obtain a series of Working Stock (WS) solutions (Table 7). The details of the final concentrations of the test items assayed are shown in Table 1. The final concentration of solvent in the assay was 2.5% and the assay volume was 100 μΐ.

Table 7: Preparation of WS solutions and final assay concentrations for MIC


[000147] Preparing the inoculum: One day before initiation of experiment, an isolated colony of S. aureus (ATCC BAA- 1556) was inoculated into sterile CAMHB and incubated at 37°C to exponential phase. After incubation, the turbidity was adjusted to that of a 0.5 McFarland Standard (approximately equivalent to 1.0 x 10 CFU/ml) and diluted to ~ 1.0 x 106 CFU/ml.

[000148] MIC Assay: The MIC assay was performed in a 96 well microtitre plate in a total assay volume of 100 μΐ (Table 7). Each well containing different concentrations of test compound (concentration range between 0.015625 and 16.0 μ§/ιη1) was inoculated with 50 μΐ of bacterial suspension (prepared from the inoculum grown overnight and adjusted approximately to 5.0 x 105 CFU/ml) along with culture control (CC, culture in broth), broth control (BC, broth only), and vehicle control (VC, 2.5% solvent in broth plus culture). The plate was incubated at 37°C for 24 hr and turbidity was measured spectrophotometrically (Absorbance microplate reader, BioTek® India, ELx800™) at 600 nm and visually. The experiment was done in duplicates. The inoculum was also plated for enumeration of bacteria. The MIC was defined as the lowest concentration of test compound that prevented bacterial growth (lack of turbidity by OD at 600 nm and visual inspection relative to no growth control). The results are shown in Table 8.

Table 8: Mean MIC of test and reference compounds on S. aureus (ATCC BAA- 1556)

Compound MIC | g ml] MIC [μΜ]

Compound 34 2.00 2.37

Mupirocin >16 >31.96

Ciprofloxacin 2.00 6.04

Linezolid 1.00 2.96