1.4.2- Dithiazoles, thermal reactions

Thermal reactions of 1,4,2-dioxazoles, 1,4,2-oxathiazoles and 1,4,2-dithiazoles are summarized in Scheme 3. The reactive intermediates generated in these thermolyses can often be trapped, e.g. the nitrile sulfide dipole with DMAD. 

Reaction of 5-phenyl-3//-l,2,4-dithiazole-3-thione (84) with 1,2-diphenylcyclopropenone leads to the SS bridged ring-opened cyclopropenone product (85) (70%) and the trithiaheterapentalene bicycle (25 R = Ph)(7%) which is believed to result from thermal decomposition of (84) (Equation... 

N-monosubstituted 1,2-diaminobenzenes react with Appel salt 20 in dichloromethane to give the corresponding 2-cyanobenzimidazoles 87 either directly or through thermal or acid-catalyzed rearrangement of the intermediate imino-l,2,3-dithiazoles 88, which can be isolated (Scheme 9). The reaction mechanism includes reversible attack of the o-amino group on the dithiazole ring <1998T9639>. 

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