Hydrochloric Acid → (2S, 4S, 5S)-5-{N-[2(R)-Benzyl-3-(morpholinocarbonyl)propionyl]-3-(4-thiazolyl)-L-alanyl}amino-6-cyclohexyl-4-hydroxy-2-isopropyl-N-methylhexanamide

Participants

Reaction Steps

A mixture of 300 mg (0.56 mmole) of (2S, 4S, 5S)-5-[N-(t-butoxycarbonyl)-3-(4-thiazolyl)-L-alanyl]amino-6-cyclohexyl-4-hydroxy-2-isopropyl-N-methylhexanamide [prepared as described in Example 1(a)] and 5 ml of a 4N solution of hydrogen chloride in dioxane was stirred at room temperature for 30 minutes. The solvent was then removed by distillation under reduced pressure. Diethyl ether was added to the residue, and the mixture was concentrated by evaporation under reduced pressure. This operation was repeated three times. After the final residue had been dried under reduced pressure for 8 hours, the dried material was suspended in 10 ml of anhydrous tetrahydrofuran. 170 mg (0.61 mmole) of 2(R)-benzyl-3-(morpholinocarbonyl)propionic acid were then added to the suspension. 0.09 ml (0.59 mmole) of 95% diethyl cyanophosphonate and 0.26 ml (1.86 mmole) of triethylamine were then added to the resulting mixture, whilst ice-cooling and under an atmosphere of nitrogen. The mixture was then stirred at room temperature for 8 hours, after which the solvent was removed by distillation under reduced pressure. The resulting residue was purified by preparative thin layer chromatography on silica gel (using a 10:1 by volume mixture of methylene chloride and methanol as the developing solvent), to afford 281 mg (yield 72%) of the title compound as white crystals, melting at 83°-86° C.

Provenance & Evidence