GB769192A - Process for the manufacture of hydroxyphenyl-serines - Google Patents

Abstract

Hydroxyphenyl serines are obtained by reacting a benzyloxybenzaldehyde with glycocoll, in the presence of an alkali metal hydroxide and a mixture consisting of methyl or ethyl alcohol and water as solvent, and subsequently splitting off the benzyl radical or radicals. The benzyl radical(s) may be split off, for example, by catalytic hydrogenation or by hydrolysis with a hydrohalic acid, especially hydrobromic acid. Suitable benzyl oxybenzaldehydes are, for example, o-, m- or p-benzyloxybenzaldehyde, 3,4-, 2,3-, 2,5-, or 3,5-di-(benzyloxy)-benzaldehyde, 2 - benzyloxy - 5 - chlorobenzaldehyde and tribenzyloxybenzaldehyde. In the examples: (a) p-benzyloxybenzaldehyde, glycocoll, alcohol, sodium hydroxide and water are heated together to give p-benzyloxyphenylserine which is hydrogenated to give p-hydroxyphenyl-serine; o-hydroxyphenyl-serine is obtained if o-benzyloxybenzaldehyde is used as starting material; (b) 2-benzyloxy-5-chlorobenzaldehyde is reacted with glycocoll in the presence of sodium hydroxide to give 2-benzyloxy-5-chlorophenyl-serine which on treating with hydrobromic acid gives 2-hydroxy-5-chlorophenyl-serine; (c) 3,4-dibenzyloxybenzaldehyde is reacted with glycocoll in the presence of sodium hydroxide to give 3,4-di-(benzyloxy) - phenyl - serine which is hydrogenated to give 3,4-dihydroxy-phenyl-serine, and (d) p-benzyloxybenzaldehyde is reacted with glycocoll in the presence of sodium hydroxide to give p-benzyloxyphenyl-serine which on hydrogenation gives p-hydroxyphenyl-serine; if o-benzyloxybenzaldehyde is used as starting material o - hydroxyphenylserine is obtained. 2 - Benzyloxy - 5 - chlorobenzaldehyde used as starting material in one example is obtained by reacting 2-hydroxy-5-chlorobenzaldehyde with benzyl chloride in the presence of potassium hydroxide.