[Synthesis of 2,3-diazaphenothiazine. XII. Dialkylaminoalkylic derivatives of 2-phenyl and 3-phenyl-10-methyl-2,3-dihydropyridazino/4,5-b/ /1,4/benzothiazin-1,4 (10 H)-dione].

The alkylation with methyl iodide and methyl sulfate of 2-phenyl-10-methyl-2,3-dihydropyridazino [4,5-b] [1,4]benzothiazin-1,4(10H)-dione (A) and the corresponding 3-phenyl substituted isomer (B) has been studied. Some derivatives of (A) and (B) substituted at the O atom with dialkyaminoalkyl groups are described; these have been subjected to pharmacological testing.