Process for the preparation of 5-fluoro-1<i>H</i>-pyrazoles

摘要

A new process for the preparation of 5-fluoro-1H-pyrazoles of the general formula (I);
is described, resulting from the reaction of an olefin of the general formula (II)
;
with hydrazines of the formula (III)
R1—NH—NH2  (III),
wherein

R1 is selected from C1-C6 alkyl, C5-C10 aryl;

R2 is a trihalomethyl moiety with at least one fluorine atom; and

R3 is selected from C1-C5 haloalkyl, CF3, C2F5, C3F7, CF2CF2Cl, CFClCF3,

in the presence of water and a base.

主权项

1. A process for synthesis of 5-fluoro-1H-pyrazole of formula (I) comprising reacting an olefin of formula (II) with a hydrazine of formula (III)
R1—NH—NH2  (III), wherein R1 is selected from C1-C6 alkyl; R2 is a trihalomethyl moiety with at least one fluorine atom; and R3 is selected from C1-C5 haloalkyl, in the presence of water and a base.