1.3.5- Triazines iminoesters

A more useful method for the synthesis of 1,2,4-tiiazine 4-oxides is the cyclization of a-hydrazonooximes 141 with orthocarboxylates or iminoesters. A variety of 1,2,4-triazine 4-oxides 55 were obtained by this methodology (71 LA 12, 73TL1429, 77LA1713, 78JMC623, 86JHC721, 87KGS257). 

Synthesis of 1,3,5-triazine derivatives from iminoesters of carboxylic acids 92KGS1587. 

Imino esters, catalyzed by trifluoroacetic acid, are trimerized in 81-85% yield with loss of alcohol. The iminoester hydrochloride salt gave the corresponding triazines in 72-78% yield in the presence of sodium acetate <92ZOR1750>. 

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