[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][N:3]=1.[N:9]1[CH:14]=[CH:13][N:12]=[C:11]2[C:15]([O:17][C:18](=O)[C:10]=12)=[O:16].C(OC(C)C)(C)C>C(OC(=O)C)(=O)C>[CH3:8][C:5]1[CH:6]=[CH:7][C:2]([N:1]2[C:15](=[O:16])[C:11]3[C:10](=[N:9][CH:14]=[CH:13][N:12]=3)[C:18]2=[O:17])=[N:3][CH:4]=12-Amino-5-methylpyridine (21.6 g.) is added to a suspension of pyrazine-2,3-dicarboxylic anhydride (30 g.) in acetic anhydride (300 cc.) at a temperature of about 25° C. The reaction mixture is stirred for 10 minutes at this temperature and then heated at a temperature of about 100° C. for 15 minutes. After cooling to a temperature of about 50° C., diisopropyl ether (600 cc.) is added and cooling is continued to 5° C. After stirring for one hour at this temperature, the insoluble product is filtered off and washed with diisopropyl ether (3×50 cc.). After drying, 6-(5-methylpyrid-2-yl)-5,7-dioxo-6,7-dihydro-5H-pyrrolo-[3,4-b]pyrazine (32 g.), which melts at 240° C., is obtained.
Wird geladen…
