N-methoxy-carbonyl 2-para-hydroxy-phenyl-glycine - prepd. by condensn. of glyoxylic acid and methyl carbamate in acetic acid and reaction of prod. with phenol and hydrogen chloride

摘要

Racemic N-methoxycarbonyl 2-(p-hydroxyphenyl)-glycine (I), is new. Used for the prepn. of DL-2-(p-hydroxyphenyl)-glycine (II) by alkaline hydrolysis of (I). (II) is an intermediate used to prepare semi-synthetic penicillins etc. (I) is prepd. by condensn. of glyoxylic acid with excess (=25%) methyl carbamate in acetic acid at room temp. and then reaction of this prod. in the same medium without isolation, with excess (10-500%) phenol and an equimolecular quantity of hydrogen chloride. The reaction mixt. is concn. to half its vol. and treated with chloroform to produce a suspension which is filtered to isolate (I). A further crop of (I) may be obtd. by heating the mother liquors at reflux with azeotropic distillation of water, in the presence of a strong acid (pref. p-toluene sulphonic acid), and filtration of the obtd. suspension.