Organic heterocyclothiazenes. Part 6. Improved synthesis of trithiadiazepines from tetrasulphur tetranitride and alkynes
- 1 January 1987
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- p. 1585-1591
- https://doi.org/10.1039/p19870001585
Abstract
In the reaction of tetrasulphur tetranitride, S4N4, with alkynes to give 1,3,5,2,4-trithiadiazepines, 1,3,5,2,4,6-trithiatriazepines, and 1,2,4- and 1,2,5-thiadiazoles, the yields of trithiadiazepines are often greatly improved (up to 8-fold) by the presence of Lewis acids, particularly titanium(IV) chloride. Thus the yield of dimethyl 1,3,5,2,4-trithiadiazepine-6,7-dicarboxylate (1) from dimethyl acetylenedicarboxylate (DMAD) is increased from 5 to 40%, formation of the trithiatriazepine (2) being totally suppressed. Trithiadiazepine formation is also much enhanced (up to 5-fold) at higher reaction temperatures (150–160 °C) than previously used (80–110 °C), though it varies very little with solvent polarity.Keywords
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