Novel Synthesis and Thermal Ring Fission of 7-Aryl-1,2,3,4,5,7-pentathiazocanes

Abstract

Treatment of 1,5,3,7-dithiadiazocanes 1 with bromine-elemental sulfur or disulfur dichloride (S2Cl2) afforded 1,2,3,4,5,7-pentathiazocanes 3, and heating of 3 caused unusual thermal ring fission to give an inseparable mixture of polysulfide chains bearing a thioformamide moiety on each terminal.

Sulfur monochloride in organic synthesis

“…21 The reaction of dithiadiazocanes 237 with sulfur monochloride affords a new class of macrocyclic polysulfides Ð 1,2,3,4,5,7-pentathiazocanes 238 in moderate to high yield. 149,150 The NMR spectra of the reaction mixture enables the suggestion that the key intermediate product of this reaction is symmetric dithia dication 239, which decomposes to dithiazole. The latter is then sulfurated by nucleophilic species that form from elemental sulfur (Scheme 123).…”

Novel Thiofomylation of Primary and Secondary Amines Using N-Aryl-1,2,3,4,5,7-Pentathiazocanes

“…1 H NMR spectra were recorded on a Bruker AC-400P (400 MHz) spectrometer, and the chemical shifts of the 1 H NMR spectra are given in δ relative to internal tetramethylsilane (TMS). 13 C NMR spectra were recorded on a Bruker AC-400P (100 MHz).…”

“…1,2 Furthermore, we also found an unprecedented thermal ring fission of the ring system of 1 to afford acyclic polysulfide 4 bearing a thioformanilide moiety on each terminal. 1 It was naturally expected that the anilino moieties on the thioformyl group of 4 or their precursors A would be easily replaced by the attack of amines possessing higher nucleophilicity than anilines to give the corresponding N-alkyl or N,N-dialkylthioformamides 5 along with generation of free anilines, and such expectation prompted us to expand the synthetic utility of cyclic polysulfides 1 for novel and environmentally benign thioformylation of amines as shown in Scheme 1. In this article, we wish to describe a full account of the convenient conversion of primary and secondary amines into the corresponding N-alkyl-and N,Ndialkylthioformamides 5 using cyclic polysulfides 1 as masked thioformylating agents.…”

Heterocyclic Chemistry of Sulfur Chlorides – Fast Ways to Complex Heterocycles

“…The thermal reaction of 1,2,3,4,5,7-pentathiazocanes 176 caused ring fission to give polysulfides 177 in low yields (Scheme 50). [65] Scheme 50.…”