反应详情

The product of Example 14, 350 mg. (0.0013 mole) was dissolved with heating in about 10 ml. of 48% aqueous hydrobromic acid to which 5 ml. of trifluoroacetic acid was added. After about 20 min. a yellow precipitate formed which was collected and dried, m.p. 328°-329° dec. Analyses for carbon, hydrogen, and nitrogen corresponded to the hemihydrate having the formula C11H6N6OS.1/2H2O. This product was also obtained, this time in anhydrous form, by hydrolysis of the product of Example 23, 0.11 mole, by heating on the steam bath for 20 min. with 100 ml. of trifluoroacetic acid and 20 ml. of 48% aqueous hydrobromic acid. The addition of water, 50 ml., and chilling of the mixture resulted in the precipitation of 11.6 g of 3-(1H-tetrazol-5-yl)-4H-pyrimido[2,1-b]benzothiazol-4-imine hydrobromide which was separated by filtration. The filtrate was concentrated by distillation which resulted in crystallization of the desired product, yield 2 g. (7%), which was recrystallized from dimethylformamide as a light yellow solid, m.p. 317.0-318.0° dec. Analyses for carbon, hydrogen, and nitrogen confirmed the formula C11H6N6OS.

1. dissolution(0.0013 mole) was dissolved
2. temperaturewith heating in about 10 ml
3. customAfter about 20 min. a yellow precipitate formed which
4. customwas collected
5. customdried
6. customThis product was also obtained
7. temperatureby heating on the steam bath for 20 min. with 100 ml
8. temperature, and chilling of the mixture