N-Trityl Candesartan Ethyl Ester synthesis

Yield:139481-59-7 85%

Reaction Conditions:

with lithium hydroxide in ethanol at 80; for 3 h;

Steps:

28 Example 28

A solution of ethyl 2-ethoxy-1-[{2'-[1-(triphenylmethyl)-1H-tetrazol-5-yl]-1,1'-biphenyl-4-yl}methyl]-benzimidazole-7-carboxylate (0.28g) and 1M LiOH (1.2 ml) in ethanol (3.5 ml) was stirred at 80°C for three hours. The reaction mixture was concentrated and washed with toluene (5x2ml). The aqueous layer was adjusted to pH 2-3 with 1 M HCl to give a white solid (0.15g, 85% yield) corresponding to 2-ethoxy-1-{[2'-(1H-tetrazol-5-yl)-1,1'-biphenyl-4-yl]methyl}-benzimidazole-7-carboxylic acid. ¹H-NMR (400MHz, DMSO) δ 1.37 (t, J=7Hz, 3H), 4.57 (q, J=7Hz, 2H), 5.62 (s, 2H), 6.95 (q, 4H), 7.17 (t, J=8Hz, 1H), 7.46 (m, 1 H), 7.5 (m, 2H), 7.6-7.7 (m, 3H) ppm.

References:

EP1833801,2008,B1 Location in patent:Page/Page column 17; 18