ethyl 4-(1-benzyl-3-hydroxy-2-oxopyrrolidin-3-yl)-5-(3-methylisoxazol-5-yl)pyrrole-2-carboxylate

ethyl 4-(1-benzyl-2-oxopyrrolidin-3-yl)-5-(3-amino-1-oxo-2-butenyl)pyrrole-2-carboxylate

ethyl 4-(1-benzyl-2-oxopyrrolidin-3-yl)-5-(diazoacetyl)pyrrole-2-carboxylate