MANUFACTURE OF ESTERS

摘要

1377651 Esters of amino acids GLAXO LABORATORIES Ltd 14 Dec 1971 [12 Jan 1971] 1528/71 Heading C2C The invention comprises (i) a process for esterifying an N-blocked amino acid by reacting said N-blocked acid with a hydrazone of general formula (wherein R2 is hydrogen or an organic group and R3 is an organic group or R2 and R3 together with the adjacent carbon atom form a cyclic organic group) in the presence of an oxidizing agent to give a compound containing an ester group of formula and (ii) the following novel esters: diphenylmethyl D( - )-phenylglycinate hydrochloride; diphenylmethyl D(- )- N - (2,2,2 - trichloroethoxycarbonyl) - 2 - phenylglycinate; diphenylmethyl 3 - acetoxymethyl - 7# - (2- thienylacetamido)ceph - 3 - em - 4 - carboxylate 1#-oxide; and esters of 2,2-dimethyl-6#-phenylacetamidopenam - 3α- carboxylic acid 1#- oxide in which the esterifying group is 21- methyldiphenylmethyl; 31 - methyldiphenylmethyl; 41 - methyldiphenylmethyl; 41- chlorodiphenylmethyl;α-. (thien - 2 - yl)- benzyl;α- methylbenzyl; fluoren - 9 - yl; fur-2-ylmethyl and cyclohexyl. Suitable oxidizing agents are organic peracids (which may be formed in situ from the organic acid and B 2 O 2 ), peresters, chromium trioxide, t-butylhypochlorite, fremys salt, chloric bromic or iodic acid, permanganic acid, ozone, N 2 O 4 , oxygen, lead tetra-acetate, MnO 2 , silver oxide and ceric salts. The process may be assisted by a catalyst such as iodine, cupric acetate, cobalt naphthenate, a ferroussalt or dibenzoyl peroxide.