Diisopropylethylamine → (2S, 4S)-2-[3-(1-Imidazolyl)azetidin-1-ylcarbonyl]-4-(4-methoxybenzylthio)-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

Participants

Reaction Conditions

Reaction Steps

3.80 g of (2S, 4S)-4-(4-methoxybenzylthio)-1-(4-nitrobenzyloxycarbonyl)-2-pyrrolidinecarboxylic acid were dissolved in 40 ml of dry acetonitrile. 1.65 g of N,N'-carbonyldiimidazole were added to the resulting solution, and the mixture was stirred at 40° C. for 1 hour. A solution of 2.00 g of 3-(1-imidazolyl)azetidine dihydrochloride [prepared as described in step (b) above] and 2.90 g of diisopropylethylamine dissolved in a mixture of 30 ml of dry acetonitrile and 5 ml of methanol was then added at room temperature to the reaction mixture, after which the mixture was stirred at the same temperature for 1 hour. At the end of this time, the reaction mixture was concentrated by evaporation under reduced pressure, and the residue was diluted with ethyl acetate. The diluted solution was washed with water and with an aqueous solution of sodium chloride, in that order. The ethyl acetate layer was separated, dried over anhydrous magnesium sulfate and concentrated by evaporation under reduced pressure. The resulting residue was subjected to silica gel chromatography to obtain 4.00 g of the title compound, as a powder, from the fraction obtained by elution with an 85:15 by volume mixture of ethyl acetate and methanol.

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