A multistep reaction of 5-halo-1,2,3-thiadiazoles and 1,2-phenylenediamines provides a new route to fused 1,3,6thiadiazepines. The overall process consists of the known stepwise formation of 5-[1-(2-aminophenyl)-1,2,3-triazol-5ylsulfanyl]-1,2,3-thiadiazole, and a novel ring transformation which involves the Smiles and Dimroth rearrangements followed by an intramolecular nucleophilic substitution of the thiol group, affording di[1,2,3]triazolo[1,5-a:5Ј,1Ј-d ]-[3,1,5]benzothiadiazepines. The influence of the substituents on the 1,2,3-thiadiazole and phenyl rings on this reaction was discussed.

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Partial molar heat capacities at infinite dilution, C l have been determined calorimetrically for o-mannitol and D-sorbitol in water, dimethyl sulfoxide and formamide, at 298:15 K. The C : values obtained, which are similar for the three solvents, are much higher than the heat capacities for the pure compounds. The large ACZ values for t h e dissolution process are believed to be partly due to t h e existence of several rotamers in solution. Sorbitol seems to be more sensitive than mannitol to specific solvent effects.

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Bis[1,2,3]triazolo[1,5-f:5',1'-b][1,3,6]thiadiazepine and [1,5-g:5',1'-b][1,3,7]thiadiazocine ring systems have been synthesized from 5-halo-1,2,3-thiadiazoles and aliphatic diamines. We have found that the last step of the process is the cyclization of initially formed bis(1,2,3-triazolyl-1,2,3-thiadiazolyl)sulfides. The structures of the intermediates and products were supported by different NMR spectroscopic methods (1H coupled 13C NMR, 2D HETCOR, HMBC and 1D INADEQUATE experiments) and mass spectrometry. Differences in the reaction pathway for aliphatic and less nucleophilic aromatic diamines were determined.