2.4- Dioxohexahydro-l,3,5-triazines

The 6-alkyl derivatives of 2,4-dioxohexahydro-l,3,5-triazine have been known for some time and have been reviewed earlier. ... 

A -alkyl-2,4-dioxohexahydro-l,3,5-triazines 33 were oxidized easily with oxygen to the corresponding cyanuric acid derivatives 34 <06M185>. 

Interestingly, methyl isocyanate is noted to form unusual trimer products in the presence of trialkylphosphine catalysts. Both the expected triazine (19) and 3,5-dimethyl-2-methylimino-4,6-dioxohexahydro-l,3,5-oxadiazine (20) products are formed (62). 

The reaction of l,3-diphenyl-2-phenyliminodiazetidinone 23 with an aryl isocyanate in the presence of hydrogen chloride affords l,3,5-triaryl-2-phenylimino-4,6-dioxohexahydro- -triazines 24." ... 

The synthesis of some 3,5-dioxohexahydro-l,2,4-triazines was described earlier (e.g., Section II,B,2,a), Other 6-substituted derivatives were prepared in the same way. ... 

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 ... 

Just as for the dioxohexahydro derivatives, substituted 3-thioxo-5-oxohexahydro-l,2,4-triazines were recently prepared by cyclization... 

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