A compound of the formula: ##STR1## and salts and esters thereof, useful as intermediates for the preparation of compounds of the formula ##STR2## wherein R.sup.1 is an alkyl group optionally substituted by one or more fluorine atoms or by an optionally substituted phenyl group R.sup.2 is No.sub.2 or Cl and R.sup.6 is a hydrogen atom or an alkyl group of 1 to 4 carbon atoms.
式为:##STR1## 的化合物及其盐和酯,可用作制备式为##STR2##的化合物的中间体,其中R.sup.1是一种烷基,可以选择地被一个或多个
氟原子或一个选择性取代的苯基所取代,R.sup.2是No.sub.2或Cl,而R.sup.6是一个1到4个碳原子的氢原子或烷基。