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In chemistry, hexahydro-1,3,5-triazine is a class of heterocyclic compounds with the formula (CH2NR)3. They are reduced derivatives of 1,3,5-triazine, which have the formula (CHN)3, a family of aromatic heterocycles.
Preparation
The parent hexahydro-1,3,5-triazine ((CH2NH)3) has been detected as an intermediate in the condensation of formaldehyde and ammonia, a reaction that affords hexamethylene tetraamine. The N-substituted derivatives are more stable. These N,N',N''-trisubstituted hexahydro-1,3,5-triazines arise from the condensation of the amine and formaldehyde as illustrated by the route to 1,3,5-trimethyl-1,3,5-triazacyclohexane:
3 CH2O + 3 H2NMe → (CH2NMe)3 + 3 H2OThe C-substituted derivatives are obtained by reaction of aldehydes and ammonia:
3 RCHO + 3 H2NR → (RCHNH)3 + 3 H2OKnown as aldehyde ammonias, these compounds characteristically crystallize with water. 1-Alkanolamines are intermediates in these condensation reactions.
The N,N,N-triacyl triazines arise from the reaction of hexamethylene tetraamine with acid chlorides or the condensation of amides with formaldehyde.
Unlike the parent triazines, the hexahydro derivatives are conformationally flexible. Trimers of isocyanates are sometimes labeled as 2,4,6-trioxohexahydro-1,3,5-triazines. They have the formula RNC(O))3. The explosive RDX is the trinitro derivative of hexahydro-1,3,5-triazine.
Hexahydro-1,3,5-triazine polymers have also been synthesized.