[(S)-4-(2,4-Difluoro-benzenesulfonylamino)-3-oxo-morpholin-2-yl]-acetic acid

[(S)-4-(4-Chloro-2,5-dimethyl-benzenesulfonylamino)-3-oxo-morpholin-2-yl]-acetic acid

N-(4-benzyloxycarbonylamidino-benzyl)-2-[3-oxo-4-phenylamino-morpholin-2-yl]-acetamide acid benzyl ester

N-(4-benzyloxycarbonylamidino-benzyl)-2-[4-(3-nitro-phenylamino)-3-oxo-morpholin-2-yl]-acetamide acid benzyl ester

N-(4-benzyloxycarbonylamidino-benzyl)-2-[(S)-4-benzenesulfonylamino-3-oxo-morpholin-2-yl]-acetamide acid benzyl ester