Patent ID: 7943779

Claim:
A process for the preparation of olmesartan medoxomil which comprises: (i) alkylating ethyl 4-(1-hydroxy-1-methylethyl)-2-propylimidazole-5-carboxylate (III) with 4-[2-(trityltetrazol-5-yl)phenyl]-benzyl bromide (IVa) or 4′-bromomethylbiphenyl-2-carbonitrile (IVb) in acetonitrile and in the presence of a base to yield a reaction suspension; (ii) crystallizing and filtering the reaction suspension, wherein acetonitrile is also used as a crystallization solvent, to obtain an ethyl ester of formula (V); and (iii) converting the ethyl ester of formula (V) to olmesartan medoxomil in a one pot process comprising: (a) hydrolyzing the ethyl ester of formula (V), (b) esterifying with a 4-substituted methyl-5-methyl-2-oxo-1,3-dioxolene (VI), and (c) subsequently deprotecting a trityl protection group.