Synthesis of thiophenes from acetylenes and -amine disulfides

Unique effects of sulfur and water on the syntheses of thiaheterocycles

“…Sodium sulfide and water act as reducing agents in the solution. Meanwhile, substituted syn-alkene (11) is formed by cis-2 and trans-2 through the additionelimination mechanism or through a three-member ring thiirene intermediate [28][29][30][31][32][33]. On the one hand, the reduction of thioether intermediate (12) leads to the formation of 5, which produces sodium disulfide at the same time.…”

The chemistry of thionitroxyl radicals

“…The preliminary results and the proposed thioketocarbene mechanism have been reported. 4 Here we present the experimental details and additional data as outlined in Table I. Yields are higher when the acetylene and disulfide are heated to 140 °C under nitrogen than when refluxed at 132 °C in chlorobenzene.…”

“…The similarity of the diphenylthiophene isomer ratio for the reactions of 1 and the piperidine disulfide with phenylacetylene and the lack of a 1,3 cycloadduct from 4 and phenylacetylene rule out the thionitrone mechanism.…”

New synthesis of 1,3-dithiole-2-thiones

“…The carbamate 2 was prepared from N-hydroxyphthalimide (1) and phenyl isocyanate in dry dioxane or dimethylacetamide. The succinimide derivative 4 was synthesized from N-hydroxysuccinimide (3) similarly.…”