[OH:1][C:2]1[CH:7]=[C:6]([OH:8])[C:5]([CH:9]([CH3:11])[CH3:10])=[CH:4][C:3]=1[C:12]([N:14]1[CH2:22][C:21]2[C:16](=[CH:17][CH:18]=[C:19]([CH2:23][N:24]3[CH2:29][CH2:28][N:27]([CH3:30])[CH2:26][CH2:25]3)[CH:20]=2)[CH2:15]1)=[O:13].[C:31]([OH:36])(=[O:35])[C@H:32]([CH3:34])[OH:33]>C(O)C>[C:31]([OH:36])(=[O:35])[C@H:32]([CH3:34])[OH:33].[OH:1][C:2]1[CH:7]=[C:6]([OH:8])[C:5]([CH:9]([CH3:10])[CH3:11])=[CH:4][C:3]=1[C:12]([N:14]1[CH2:22][C:21]2[C:16](=[CH:17][CH:18]=[C:19]([CH2:23][N:24]3[CH2:29][CH2:28][N:27]([CH3:30])[CH2:26][CH2:25]3)[CH:20]=2)[CH2:15]1)=[O:13]The product of Step 12 (646 g, 1.58 mol) was dissolved in ethanol (5.17 L) and the solution filtered. A solution of L-lactic acid (142 g, 1.58 mol) dissolved in ethanol (2.59 L) was filtered and added to the solution of the filtered solution (above) and then to the mixture was added EtOAc (7.75 L). The suspension was stirred at RT for 12 h and then cooled to 5° C. for a further 2 h. The solid which had formed was removed by filtration, washed with EtOAc (2×2.58 L) and heptane (2×1.94 L) and dried to constant weight at 35° C. giving the title compound (581 g, 74% yield).
Wird geladen…