Synthesis and chemical properties of tetraalkyl-substituted thiourea adducts with chlorine (original) (raw)
2005, Main Group Chemistry
1,3-Dialkyl-4,5-dimethylimidazole-2-thiones 1a, 1b and acyclic N,N,N',N'-tetramethylthiourea 3 react with sulfuryl dichloride to yield a new type of sulfur ylides, 1,3-dialkyl-4,5dimethylimidazol-2-ylidenesulfonium dichloromethylides 2a, 2b and bis(dimethylamino)methylenesulfonium dichloromethylide 4, respectively. The reaction of 2a and 4 with acetylacetone results in the formation of thione S-ylides 5 and 6, whereas the reaction with dimethyl(trimethylsilyl)amine leads to the formation of S-dimethylaminothiouronium chlorides 8a, 8b, and 9, respectively. Anion metathesis of 8a, 8b, and 9 with NaX affords compounds 10a-10c, 11a, and 11b (X = BPh 4 , BF 4). Compounds 8a and 9 are involved in a [3 + 2] cycloaddition reaction when treated with dimethyl acetylenedicarboxylate, resulting in salt-like derivatives of isothiazolines 12-15. These new compounds have been characterized by spectrometric and elemental analyses, and the solid-state structure of compound 10a has also been determined by single-crystal X-ray structural analysis.