(R)-3-(tert-butoxycarbonylamino)-4-(2,4,5-trifluorophenyl)butanoic acid → 7-[(3R)-3-[(tert-Butoxycarbonyl)amino]-4-(2,4,5-trifluorophenyl)butanoyl]-8-(cyclopropylmethyl)-2-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-alpha]pyrazine

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Reaktionsschritte

A 35 mg portion of 8-(cyclopropylmethyl)-2-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-α]pyrazine hydrochloride was coupled to (3R)-3-[(tert-butoxycarbonyl)amino]-4-(2,4,5-trifluorophenyl)butanoic acid essentially following the procedure outlined in Example 2, Step D, with the following exception. The reaction mixture was stirred at ambient temperature for 24 h and then concentrated. The residue was purified by preparative TLC (silica gel, 10% methanol/dichloromethane) to provide 54 mg of the title compound as a mixture of diastereomers. The diastereomers were separated by HPLC (OD chiralcel column, 7% ethanol/hexane) to give the faster eluting diastereomer and the slower eluting diastereomer.

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