Benzenebutanoic acid, alpha-bromo-, ethyl ester → t-Butyl alpha-{6(R)-[1-ethoxycarbonyl-3-phenylpropylamino]-5-oxo-3(S)-(2-thienyl)perhydro-1,4-thiazepin-4-yl}acetate

Participants

Reaction Steps

344 mg of t-butyl α-[6(R)-amino-5-oxo-3(S)-(2-thienyl)perhydro-1,4-thiazepin-4-yl]acetate [prepared as described in step (g) above] were subjected to N-alkylation with 406 mg of ethyl 2-bromo-4-phenylbutyrate in the manner described in Example 1(h). The reaction product was subjected to silica gel column chromatography using a 1:20 by volume mixture of ethyl acetate and methylene chloride as eluent, which separated the compound into two isomers, A and B, (ascribed to the asymmetric carbon atom to which the phenethyl group is attached). Isomer A (in which the carbon attached to the phenethyl group had the R-configuration) was eluted first as an oily compound in a yield of 0.17 g.

Provenance & Evidence