Hydrochloric Acid → tert-Butyl 4-{3-({[2-({1-[(1-Adamantylamino)carbonyl]-(1S)-3-benzyloxy-3-oxopropyl}amino)-2-oxoethyl]amino}carbonyl)-5-[1-(tert-butoxycarbonyl)-4-piperidyl]pentyl}tetrahydro-1(2H)-pyridinecarboxylate

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Reaction Steps

Isobutyl chloroformate (1.7 g, 12.4 mmol) is added, at room temperature, to a solution of 2-[(4-[1-(tert-butoxycarbonyl)-4-piperidyl]-2-{2-[1-(tert-butoxycarbonyl)-4-piperidyl]ethyl}butanoyl)amino]acetic acid (compound 4) (6.9 g, 11 mmol) in 150 ml of ethyl acetate and N-methylmorpholine (5 g, 49.5 mmol). A white suspension is obtained. After stirring for 10 minutes, a solution of benzyl (3S)-3-amino-4-(1-adamantylamino)-4-oxobutanoate trifluoroacetate (6.9 g, 11.2 mmol) in 20 ml of ethyl acetate is added. Stirring is continued at room temperature for 18 hours. 2N hydrochloric acid is added. The organic phase is washed with water, dried over sodium sulphate and evaporated to give the crude product, which is purified by flash chromatography (20/1 dichloromethane/methanol) to give 6.6 g of a beige-coloured solid.

Provenance & Evidence