[N:1]([O-:3])=O.[Na+].[Cl:5][C:6]1[CH:7]=[C:8]([CH2:12][CH2:13][C:14](=[O:21])[CH2:15][C:16]([O:18][CH2:19][CH3:20])=[O:17])[CH:9]=[CH:10][CH:11]=1>O.C(O)(=O)C>[Cl:5][C:6]1[CH:7]=[C:8]([CH2:12][CH2:13][C:14](=[O:21])[C:15](=[N:1][OH:3])[C:16]([O:18][CH2:19][CH3:20])=[O:17])[CH:9]=[CH:10][CH:11]=1A solution of sodium nitrite (12.6 g) in water (25 ml) was added to a stirred solution of the product from step (i) (42.2 g) in acetic acid (50 ml) at <30° C. The reaction mixture was stirred at room temperature for 30 min. Water (75 ml) was added and the mixture was stirred for 2 hours and extracted with diethyl ether. The combined extracts were washed with water and saturated aqueous sodium bicarbonate solution. The organic layer was collected, dried (MgSO4) and solvent evaporated under reduced pressure to give the subtitle product.
Wird geladen…