Process for the preparation of 3-haloalkylpyrazoles

摘要

The present invention provides a process for the preparation of a compound of formula (I) wherein R1 is C1-C4 haloalkyl; R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl; and R3 is methyl or ethyl; comprising reacting a compound of formula (IV) wherein R1, R2 and R3 are as defined for the compound of formula I; with an alkylating agent in the presence of an amide.;

主权项

1. A process for the preparation of a compound of formula I: wherein R1 is C1-C4 haloalkyl; R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl; and R3 is methyl or ethyl; comprising reacting a compound of formula II: wherein R1 and R2 are as defined for the compound of formula I; with an alkylating agent in the presence of an amide; wherein the process comprises N alkylating the compound of formula II and isomerising the compound of formula IV wherein R1, R2 and R3 are as defined for the compound of formula I; produced from the alkylation at substantially same time; wherein the alkylating agent is a compound of formula III: wherein R3 is methyl or ethyl; wherein the amide is present in an amount of 0.1 molar equivalents to 10 molar equivalents relative to the amount of the compound of formula IV and the compound of formula I.