Patent ID: 6288297
Filing Date: 2001-09-11
Classification: C07C

Abstract:
A process for synthesis of a compound of formula (IV); ##STR61##wherein:R.sup.1 is selected from:C.sub.1-10 alkyl substituted with 0-3 R.sup.4,C.sub.2-6 alkenyl substituted with 0-1 R.sup.4,C.sub.3-10 cycloalkyl substituted with 0-2 R.sup.5,C.sub.3-6 carbocyclic ring substituted with 0-2 R.sup.5, andaryl substituted with 0-2 R.sup.6 ;R.sup.4, at each occurrence, is selected from OR.sup.7, NR.sup.7 R.sup.7a, phenyl, and cyclopropyl;R.sup.5, at each occurrence, is selected from D, methyl, ethyl, propyl, methoxy, ethoxy, and propoxy;R.sup.6, at each occurrence, is selected from methyl, ethyl, propyl, methoxy, ethoxy, propoxy, F, Cl, B, I, CN, and NR.sup.7 R.sup.7a ;R.sup.7 and R.sup.7a are independently selected from methyl, ethyl, propyl, and butyl;said process comprising:(1) contacting an aldehyde of formula R.sup.1 --CHO with trichloroacetic acid or tribromoacetic acid, in the presence of a base catalyst to form a compound of formula (II): ##STR62##wherein R.sup.2a, R.sup.2b, and R.sup.2c are Cl or Br;(2) contacting a compound of formula (II) with a hydroxy group protecting agent in the presence of a coupling catalyst and an acid scavenger, in a suitable nonaqueous solvent to form a compound of formula (III) ##STR63##wherein --X' is a hydroxy protecting group; and(3) contacting a compound of formula (III) with a strong base to form a compound of formula (IV).