Ab initio Calculations of a formation reaction of a triazine ring were perf
ormed. From the model substrate, methyl cyanate, a concerted association pa
th with C-3h symmetry was first examined. In terms of energy changes, this
path was found to be unlikely. Second, a stepwise path assisted by a water
cluster was tested. But, this path was found to be of a relatively high amo
unt of activation energy in the first additional step. Third, a zinc format
e was used as a catalyst, and the reaction was computed to have a reasonabl
e stepwise route for formation of the six-membered triazine ring. Fourth, t
he reaction promoted by a hydronium ion was shown to generate a ring-closur
e mechanism similar to that caused by the zinc catalyst. Thus, the crucial
role of catalysts coordinated to the sigma lone-pair orbital of the cyanate
nitrogen atom was verified.