Mesoionic dimethyl derivatives of some 1,2,4-triazinones. The course of the reaction of 3,5-dimethoxy, 3-methoxy-5-methylthio, 5-methoxy-3- methylthio and 3,5-bis(methylthio)-1,2,4-triazine with methyl iodide
(1a) with methyliodide was found to give depending on the reaction time triazinium iodide 2a, triaziniumolates 4a and 6a as well as methoxytriazinones 7a and 8a. Thermolysis of 2a gave triaziniumolates 4a and 6a. Reaction of 2a, 4a or methoxytriazinone 9a with methyliodide in acetonitrile yielded as the sole product 6a. Reaction of 3-methoxy-5-methylthio-1,2,4-tri-azine (1b) with methyliodide gave triazinium