55383-59-0 6-Amino-4-methylamino-7H-pyrimido(4,5-b)(1,4)thiazine 7H-Pyrimido(4,5-b)(1,4)thiazine, 6-amino-4-methylamino- 7H-Pyrimido(4,5-b)(1,4)thiazine-4,6-diamine, N4-methyl-