Regioselective synthesis of 1-methyl-3-hydroxy-5-perfluoroalkylpyrazoles by the addition of methylhydrazine to perfluoroalkylacetylenic esters
作者:Bruce C. Hamper
DOI:10.1016/s0022-1139(00)82607-x
日期:1990.6
1H,3H)pyrazoles has been developed. Treatment of perfluoroalkylacetylenic esters with methylhydrazine in methanol-water at 0° or in methylene chloride at low temperature leads to 1-methyl-3-hydroxy-5-perfluoroalkyl(1H,3H)pyrazoles in a regioselective manner. Structuralassignments of the regioisomers are based on 13C nmr chemical shifts, long range carbon-fluorine and carbon-proton coupling. The effect
已开发出对1-甲基-3-羟基-5-全氟烷基(1H,3H)吡唑的区域选择性途径。在甲醇-水中于0°或在二氯甲烷中于低温下用甲基肼处理全氟烷基炔属酸酯会以区域选择性方式生成1-甲基-3-羟基-5-全氟烷基(1H,3H)吡唑。区域异构体的结构分配基于13 C nmr化学位移,远距离碳氟和碳质子偶合。讨论了乙炔结构对反应区域选择性的影响。
[EN] METHOD FOR MANUFACTURING 1 - ALKYL - 3 - DIFLUORMETHYL - 5 - HYDROXYPYRAZOLES<br/>[FR] PROCÉDÉ POUR LA FABRICATION DE 1-ALKYL-3-DIFLUOROMÉTHYL-5-HYDROXYPYRAZOLES
申请人:BAYER CROPSCIENCE AG
公开号:WO2011144549A1
公开(公告)日:2011-11-24
The present invention relates to a process for preparing 1-alkyl-3-difluoromethyl-5-hydroxypyrazoles, which are valuable intermediates for the production of fungicides: i. e. Process for preparing 1-alkyl-3-difluoromethyl-5-hydroxypyrazoles of the formula (I) in which R1 is a linear or branched C1-C6-alkyl group, comprising the reaction of alkyl difluoroacetoacetates of the formula (II) in which R2 is a linear or branched C1-C6-alkyl group, with alkylhydrazines of formula (III) NH2-NH-R1 (III) in the presence of an organic acid and of a solvent.
HAMPER, BRUCE C., J. FLUOR. CHEM., 48,(1990) N, C. 123-131
作者:HAMPER, BRUCE C.
DOI:——
日期:——
Substituted 3-hydroxy pyrazoles
申请人:Monsanto Company
公开号:US04855442A1
公开(公告)日:1989-08-08
The present invention relates to a class of 5-haloalkyl-3-hydroxy-1-(C.sub.1-2 alkyl)pyrazoles useful as precursors for an active class of phenoxypyrazole herbicides.