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

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Reaktionsschritte

A 160 mg portion of [2-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-α]pyrazin-8-yl](cyclopropyl)methanol 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. Purification by preparative TCL (silica gel, 10% methanol/dichloromethane) gave 176 mg of the product as a mixture of diastereomers. HPLC (OD chiralcel column, 6% ethanol/hexane) separated the first and last eluting diastereomers. The middle fractions containing two diastereomers were further subjected to HPLC (OD chiralcel column, 3% ethanol/hexane) to provide the second and the third eluting diastereomers.

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