Ammonium formate → HCID 178447302, compound

Participants

Reaction Conditions

Reaction Steps

1.0 g (1.5 mmoles) of 4-isopropyl-3-pentanoyl-2-[2′-(1-trityl-1H-tetrazol-5-yl)-biphenyl-4-yl]oxazolidin-5-one are reacted in 50 ml of N,N,-dimethyl-acetamide with 1.2 g of ammonium formate (19.0 mmoles) and 1.2 g of 5% Pd/C catalyst. The temperature is raised to 90° C. and ammonium formate is added in 1.2 g (19.0 mmoles) portions, at 2 hours interval, until disappearance of the starting substrate. The mixture is cooled and the catalyst is filtered off. tert-Butyl methyl ether and 20% sulfuric acid are added to about pH 2, then sodium chloride to saturation of the aqueous phase. The organic phase is separated and washed with water 3 times. The organic phase is alkalinised with a 10% sodium hydroxide solution. The aqueous phase containing the salified product is separated and washed with tert-butyl methyl ether. Ethyl acetate is added and acidified with a 5% hydrochloric acid solution. The organic phase is separated, dried over sodium sulfate, filtered and concentrated under reduced pressure to a residue. Crystallization from isopropyl ether affords 0.44 g of valsartan (1.05 mmoles; yield: 70%), having purity higher than 99.5% and content in azide derivatives lower than 20 ppm.

Provenance & Evidence