... J. Org ... Chem., Vol. ... The combined organic layers were dried, filtered, evaporated, and pumped at lo-, mm for 2 h to yield N- [3- [ [4- [p- [(benzyloxycarbonyl)amino]ethyl]phenyl]oxy]- propanoyl]-~-proline (9): 6.2 g (70%); [.D -32.6O (c 0.8, ethanol); 'H NMR (CDCl,, Me4Si) 6 2.32 ( ...