4-Para-bi:phenylyl 4-oxo 2-methyl butyric acid prepn. - by condensn. of 4-bromo:acetyl-bi:phenyl with di:ethyl methyl-malonate carbanion, saponification and decarboxylation

摘要

The prepn. of 4-para-biphenylyl-4-oxo -2-methyl-butyric acid ((I) or Metbufene) is by (a) condensn. of 4-bromacetylbiphenyl (II) with diethyl-methyl malonate carbanion (III) in an organic solvent (b) saponification of the obtd. diester (IV) to give 4-p-bephenyl-4-oxo -2-methyl-2-carboxy-butyric acid (V), which is decarboxylated to yield (I). (II) and (III) carbanion are used in stoichiometric amts. and the condensation effected in hexamethyl-phosphorotriamide (HMPT). The carbanion of (III) is pref. obtd. by treatment with sodium hydride in HMPT. (IV) is saponified with NaOH and (V) decarboxylated by heating in acid medium in decatin. (I) is known medicament, normally prepd. by acylation of biphenyl with itaconic anhydride and reduction of the methylenic double bond.