| 1-benzyl p-nitrophenyl ester, l-2-pyrrolidinedicarboxylic acid |
| 1-benzyl p-nitrophenyl l-1,2-pyrrolidinedicarboxylate |
| carbobenzyloxy-l-proline p-nitrophenyl ester |
| carbobenzyloxy-l-prolin p-nitrophenyl ester |
| n-cbz-l-proline p-nitrophenyl ester*crystalline |
