[CH2:1]([O:3][C:4]([CH2:6][C:7]([N:9]1[CH:14]([C:15]([O:17][C:18]([CH3:21])([CH3:20])[CH3:19])=[O:16])[CH2:13][CH2:12][CH2:11][N:10]1C(OCC1C=CC=CC=1)=O)=[O:8])=[O:5])[CH3:2]>CO.[Pd]>[CH2:1]([O:3][C:4]([CH2:6][C:7]([N:9]1[CH:14]([C:15]([O:17][C:18]([CH3:19])([CH3:21])[CH3:20])=[O:16])[CH2:13][CH2:12][CH2:11][NH:10]1)=[O:8])=[O:5])[CH3:2]A solution of 25.3g of 1-benzyl 3-tert.butyl 2-(2-ethoxycarbonylacetyl)hexahydropyridazine-1,3-dicarboxylate in 500 ml of methanol was hydrogenated over 2.3g of 10% palladium/carbon at room temperature and under atmospheric pressure. The catalyst was removed by filtration. Evaporation of the filtrate and recrystallization of the residue from hexane gave 16.9 g (97%) of tert.butyl 2-(2-ethoxycarbonylacetyl)hexahydropyridazine-3-carboxylate having a melting point of 86°-87° C.
불러오는 중…