Dithiazolyl synthesis

Oxidation of carbon side-chains has resulted in the synthesis of dithiazolyl ketone (82) and thiazolyl phenyl ketone (83). The hydrocarbon chain can also be dehydrogenated in acetic acid in the presence of... 

The general synthetic methodology to benzo-fused dithiazolyl radicals has been extended to the synthesis of di- and tri-radicals. Of these the benzo-1,2 4,5- /h.v(l,3,2-dithiazole) system has been studied in its full range of oxidation states, i.e. 34, 35 and 36 (Scheme 9). 

Synthesis of 1,2,3-dithiazoles is the most extensively studied. The widely used and very long-known Herz reaction of arylamines with S2CI2 to give benzo-l,2,3-dithiazolium salts (Section 4.11.8.5) has been extended to hetarylamines (Scheme 17). More importantly, a new impetus for its investigation and development was provided when benzo-l,2,3-dithiazolyl radicals were shown by Mayer and co-workers to be intermediates. The reaction in a modified form was transformed by the above authors to an effective method for synthesis of this new class of stable radicals. When applied to acyclic enaminoketones the thiosulfinylamine precursor of the free radical could be isolated (Scheme 18). It was also extended to cyclic and acyclic oximes to afford fused and monocyclic... 

Research in the reviewed period 1995-2005 has covered more the chemistry of 1,3,2-dithiazoles and less the chemistry of 1,3,2-dioxazoles. 1,3,2-Oxathiazoles and their derivatives were not investigated in this period. Much attention has been paid to the neutral 1,3,2-dithiazolyl radicals including their synthesis, theoretical and structural study, and application. Special attention was given to their magnetic properties and conductivity. 1,3,2-Benzodithiazole. Y-oxidcs were of interest as enantiomeric compounds and intermediates for the preparation of enantiopure amines and alcohols. 

Synthesis of 1,3,2-dithiazoles has been the most extensively studied. Various structural types of these compounds have been synthesized in 1990s from raV-dithiols, bis(sulfenylchlorides), and alkynes <1996CHEC-II(4)433>. Much attention has been paid to the preparation of stable 1,3,2-dithiazolyl radicals and, especially, cations. The synthetic potential of 1,3,2-oxathiazoles and 1,3,2-dioxazoles is restricted by several uncommon procedures including nitrosation of thiolcarboxylic acids and photochemical addition of nitrobenzene to alkenes <1996CHEC-II(4)433>. 

---