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1. WO1986003490 - PROCEDE DE PREPARATION D'ISOXAZOLES 3,5-DISUBSTITUES

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

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CLA1MS
1. A process for the preparation of 3,5-disubstituted isoxazoles characterized in that a dihaloformaldoxime is reacted with an excess of an 1 -alkyne derivative in the presence of an alkaline base in an inert solvent.
2. A process according to claim 1, characterized in that the dihaloformaldoxime is dichloroformaldoxime or dibromoformaldoxime.
3. A process according to any one of claims 1 and 2, characterized in that dibromo- or dichloroformaldoxime is reacted with an 1 -alkyne derivative of formula R-C≡CH wherein R is hydrogen, phenyl or 1-6 C alkyl optionally substituted by halogen, OH, OR', CHO, COR', C00R', CONH , CONR'R", -NHCOR* where in turn R' and R", the same or different, are an 1-6C alkyl or haloalkyl.
4. A process according to any one of claims from 1 to 3, characterized in that the 1 -alkyne derivative is added in excess of from 2 to 5 time in mol with respect to the dihalofor aldoxi-me.
5. A process according to any one of claims from 1 to 4, characterized in that the alkaline base is added in at least equimolecular amount with respect to the dihaloformaldoxime.

6. A process according to claim 5, characterized in that the alkaline base is sodium and potassium carbonate or bicarbonate.

7. A process according to any one of claims from 1 to 6, characterized in that the inert solvent is an organic solvent in which the 1-alkyπe derivative is soluble.
8. A process according to any one of claims from 1 to 7, characterized in that the solvent is a mixture of an organic solvent in which the 1 -alkyne derivative is soluble and of water in an amount of between 0.1 and 1% by volume with respect to the organic solvent.
9. A process according to any one of claims from 1 to 8, characterized in that the reaction is performed at room temperature.