4-Methylmorpholine → Acetylprolylalanylprolyl-2-azaalanyl-l-lactic acid ethyl ester

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Reaction Steps

Acetylprolylalanylproline (2 mmole) is dissolved in methylene chloride (5 ml) containing N-methylmorpholine (2 mmole) and diluted with dry tetrahydrofuran (400 ml). To this stirred solution at -20° to -25° is added isobutyl chloroformate (2 mmole) and the mixture is stirred for 15 minutes. A solution of 2-azaalanyl-l-lactic acid ethyl ester (2 mmole) in tetrahydrofuran (2 ml) is then added. The mixture is allowed to warm to room temperature over a period of 1 hour and stirred for a further 3 hours. The mixture is filtered, and the filtrate is evaporated to dryness. Chromatography on silica gel (38 gm) and elution with 5% methanol in chloroform gives acetylprolylalanylprolyl-2-azaalanyl-l-lactic acid ethyl ester.

Provenance & Evidence