6- Azauracil dihydro

In agreement with the results of Cattelain, further methylation of the 3-methylmercapto derivative (96) results practically exclusively in 2-methyl-3-methylmercapto-5-oxo-2,5-dihydro-l,2,4-triazine (97). Further methylation of 5-methylmercapto derivative (90) yields 2-methyl-5-methylmercapto-3-oxo-2,3-dihydro-l,2,4-triazine (100). Their structure was confirmed by acid hydrolysis leading to 2-methyl-3,5-dioxo derivatives (62), As was already mentioned, this reaction is a suitable general procedure for preparing the 1-alkyl derivatives of 6-azauracil. ... 

Dioxohexahydro-l,2,4-triazine (dihydro-6-azauracil) (128) yields a diacetyl derivative (129) which is relatively stable toward hydrolysis. The acetylation of the iV-methyl derivatives and the course of the reaction with diazomethane indicates that acetylation takes place here in positions 1 and 2 ... 

Alkylation reactions were recently performed with all the thio derivatives of 6-azauracil and 6-azathymine. In agreement with previous findings, the methylmercapto derivatives were obtained by alkylation of all these substances in alkaline solution. Thus, e.g., 3-ihethylmercapto-6-oxo-2,5-dihydro-l,2,4-triazine (96), 5-methylmer-capto-3-oxo-2,3-dihydro-l,2,4-triazine (90), and 3,5-dimethylmer-capto-l,2,4-triazme (91) were obtained. The last-named of these was... 

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