REARRANGEMENT REACTIONS IN SOLID STATE ORGANIC COMPOUNDS. M. Kaftory, E. Handelsman-Benory, M. Botoshansky, Department of Chemistry, Technion Israel Institute of Technology, 32000 Haifa, Israel

Few known examples of rearrangement reactions in the solid state will be briefly described. An interesting example of solid state reaction is the stepwise methyl rearrangement of 2,4,6-trimethoxy-1,3,5-triazine (I) to 1,3,5-trimethyl-2,4,6-trioxohexahydro-s-triazine (IV) through (II) and (III). Studies by MS and NMR [1,2], have shown that the methyl

migration in the melt is intermolecular. Also, it was found that some of the rearrangement steps occur in the solid state. We have studied the thermal behavior of each compound by HTXRD, by DSC and analyzed the topochemistry of the rearrangements from their crystal structures. We have found that steps 1 and 3 are taking place in the melt while step 2 in the solid. The crystal structure of (II) shows that methyl migration can take place by two routes: "Homo Chain Mechanism" will lead to compound (III) and "Hetero Ribbon Mechanism" will produce (IV). Thermal behavior studies suggest that both reactions are practically taking place. Kinetic study of the solid state rearrangement found for step 2 will be described.

Compounds of type (V) shown to undergo methyl migration either in the solid state or in the melt. In one of the compounds a color change was observed whose nature is under investigation.

[1] Tosato, M. L. (1982). J. Chem. Soc. Perkin Trans. II, 1321.

[2] Tosato, M. L. (1984), J. Chem. Soc. Perkin Trans. II, 1593.