申请人:Sandoz Ltd.
公开号:US05670648A1
公开(公告)日:1997-09-23
The invention discloses a novel process for the preparation of a compound of formula II ##STR1## wherein R.sub.1 is C.sub.1-5 alkyl, R.sub.2 is hydrogen or C.sub.1-5 alkyl, and R.sub.3 is optionally substituted phenyl, comprising the reaction of a 4-hydroxypyrazole of formula III ##STR2## wherein R.sub.1 and R.sub.2 are as defined for formula II, with a benzylhalide of formula IV Hal--CH.sub.2 --R.sub.3 (IV) wherein Hal is halogen, preferably bromine or chlorine, and R.sub.3 is as defined for formula II, in the presence of a base. The invention further comprises a novel process for the preparation of the 4-hydroxypyrazole of formula III. The compounds of formulae II and III are intermediates for highly effective systemic fungicides of the class of pyrazolyl acetic acid derivatives.
该发明揭示了一种制备式II化合物的新工艺,其中R.sub.1是C.sub.1-5烷基,R.sub.2是氢或C.sub.1-5烷基,R.sub.3是可选择取代的苯基,包括式III的4-羟基吡唑的反应##STR2##其中R.sub.1和R.sub.2如式II所定义,与式IV的苄基卤化物的反应Hal--CH.sub.2--R.sub.3 (IV)其中Hal是卤素,优选溴或氯,R.sub.3如式II所定义,在碱存在下。该发明还包括一种制备式III的4-羟基吡唑的新工艺。式II和III的化合物是高效系统杀菌剂的中间体,属于吡唑基乙酸衍生物类。