Preparing 5-fluoro-1-alkyl-3-fluoroalkyl-1H-pyrazole-4-carbaldehydes
View Patent ↗The present invention relates to a novel process for preparing 5-fluoro-1-alkyl-3-fluoroalkyl-1H-pyrazole-4-carbonyl chlorides, a useful intermediate in the manufacture of fungicides.
1. A compound of formula (IV)
where R 1 represents C 1 -C 6 -alkyl and R 2 is selected from the group consisting of CF 2 H, CF 2 Cl, CCl 2 F, C 2 F 5 or C 3 F 7 .
2. The compound of formula (IV) according to claim 1 where R 1 represents methyl, ethyl, n-propyl, isopropyl, butyl, pentyl.
3. The compound of formula (IV) according to claim 1 , where R 1 represents methyl and R 2 represents CF 2 H.
4. 5-Fluoro-1-methyl-3-difluoromethyl-1H-pyrazole-4-carbaldehyde.
5. A process for preparing a compound of formula (IV)
where R 1 represents C 1 -C 6 -alkyl and R 2 is selected from the group consisting of CF 2 H, CF 2 Cl, CCl 2 F, C 2 F 5 , or C 3 F 2 ,
wherein said process comprises reacting a compound of formula (II)
where R 1 and R 2 are as defined above,
with a fluorinating agent of formula (III)
M + F − (III)
where M + represents Li + , Na + , K + , Cs + , Alk 4 N + and Alk represents C 1 -C 4 -alkyl, and optionally in the presence of a phase transfer catalyst.