Preparation of imidazole derivatives, useful as intermediates for angiotensin II receptor antagonists, by cyclization of aminoacrylate esters

摘要

Alkylphosphonic acid anhydrides are used a cyclizing agents in conversion of aminoacrylate esters of formula (II) to imidazole derivatives of formula (I). Preparation of imidazole compounds of formula (I), or salts of (I), comprises: (a) cyclization of an aminoacrylate ester of formula (II), in the presence of an alkylphosphonic anhydride, to a compound of formula (I); (b) purification of (I) by salt formation and optional recrystallization; and optionally; (c) cleavage of residues which may be present to protect functional groups. R1 = H; 1-8C alkyl (optionally substituted by 1-3 F, Cl, Br, CF3, Me, MeO, NO2 or NR6R7); Q-Cy; Q-Ph; or Q-Het; R2, R3 = SR4 or COOR5; R4, R5 = 1-8C alkyl (optionally substituted by 1-3 F, Cl, Br, CF3, Me, MeO, NO2 or NR6R7); Q-Cy; Q-Ph; or Q-Het; Cy, Ph, Het = 3-7C cycloalkyl, phenyl (optionally substituted by 1-3 F, Cl, Br, CF3, NO2, Me, MeO, OH or NR6R7) and heteroaryl (containing 1-9C atoms and optionally substituted by 1-3 F, Cl, Br, CF3, NO2, Me, MeO, OH or NR6R7) respectively; Q = CnH2n; R6, R7 = 1-4C alkyl