The syntheses of [1,2,5]thiadiazolo[3,4-b]pyrazine (3) and its methyl and/or phenyl derivatives as well as their reduction to 2,3-diaminopyrazines 4 are described. ... The cleavage of fused pyrazines represents a useful method for the synthesis of substituted pyrazines.2 We have pre- viously reported the synthesis of 2,3-diaminopyrazines via hydrogenolysis of furazano[3,4-b]pyrazines which were pre- pared by the condensation of ...
![5,6-diphenyl-[1,2,5]thiadiazolo[3,4-b]pyrazine Structure](https://image.chemsrc.com/caspic/339/112230-77-0.png)
![5,6-dimethyl-[1,2,5]thiadiazolo[3,4-b]pyrazine Structure](https://image.chemsrc.com/caspic/174/59503-57-0.png)
