82009-34-5

Synthesis

Cilastatin, (Z)-7-[(2-amino-2-carboethoxyethyl)thio]-2-[[2,2-dimethylcyclopropyl) carbonyl] amino]-2-heptenoic acid (32.1.3.6), is synthesized from the ethyl ester of 1,3-dithian-2-carboxylic acid (which is ethyl glyoxylate, protected at the aldehyde group with 1,3-propanedithiol), which is alkylated by 1,5-dibromopentane in the presence of sodium amide, forming the ethyl ester of 7-bromo-2-[2-(1,3-dithiano)]hepthanoic acid (32.1.3.2). Oxidative hydrolysis of this product with N-bromosuccinimide in a mixture of acetonitrile–water solvents leads to the formation of the ethyl ester of 7-bromo-α-ketoheptanoic acid (32.1.3.3). Acidic hydrolysis of this product using hydrogen bromide in acetic acid gives 7-bromo-α-ketoheptanoic acid (32.1.3.4). This is reacted with 2,2-dimethylcyclopropancarboxylic acid amide to form the corresponding enamide, (Z)-7-bromo-2-(2, 2-dimethylcycloprotancarboxamido)-2-heptenoic acid (32.1.3.5). The resulting product is used for S-alkylation of L-cysteine, which results in the production of the desired cilastatin (32.1.3.6).