Reissert compound studies. LXVII. The pyrido[3,4-b]pyrazine reissert compound

The pyrido3,4-b]pyrazine systems investigated were found to form Reissert compounds in the presence of an acyl halide (or chloroformate) and trimethylsilyl cyanide. Only the mono Reissert compounds were isolated. In the case of 2,3-diphenylpyrido3,4-b]pyrazine ( 7 ), its reaction with benzene sulfonyl chloride and trimethylsilyl cyanide gave 5-cyano-2,3-diphenylpyrido3,4-b]pyrazine ( 16 ). Alkylation of the Reissert compound 11 and analog 12 either directly gave the alkylated hetercyclic base or the alkylated Reissert analog compound.