5‐Morpholino‐1,2,3,4‐thiatriazole as a Sulfur‐Transfer Reagent in the Reactions with Thioketones

Abstract

The thermal decomposition of 5-morpholino-1,2,3,4-thiatriazole (7), which leads to the extrusion of an active form of sulfur, in the presence of different thioketones is described. The interception of the S-atom by the C=S bond leads to in situ formation of an elusive thiocarbonyl S-sulfide of type 5. This intermediate is a prone 1,3-dipole, which undergoes effectively [2+3] cycloadditions with thioketones to yield 1,2,4-trithiolane derivatives in a regioselective manner. Unexpectedly, 3,3-dichloro-2,2,4,4-tetramethyl-3-thioxocyclobutanone (1c) does not lead to the expected symmetrical 1,2,4-trithiolane. This result can be explained by the reduced stability of the corresponding thiosulfine 5c. Three-component reactions, which were carried out in the presence of equimolar amounts of two different thioketones, result in the formation of 'mixed' 1,2,4-trithiolanes of type 8.

Generation and Rearrangement of Some Spirocycloaliphatic Thiosulfines and Dithiiranes

“…1,2,4‐Trithiolanes 19 – 21 are crystalline, stable compounds that are accessible by sulfur‐transfer reactions by using the parent thioketones, that is, 2,2,4,4‐tetramethyl‐3‐thioxocyclobutanone ( 22 ),10 3,3‐dichloro‐2,2,4,4‐tetramethylcyclobutanethione ( 23 ),11 or adamantanethione ( 24 ),12 respectively (Scheme ). Reactions are postulated to occur via the in situ generated thiosulfines, which subsequently undergo regioselectively the [2+3] cycloaddition with the C=S bond to yield heterocyclic products 19 – 21 .…”

“…Starting Materials: 1,2,4‐Trithiolanes used in the study were obtained according to known literature protocols: 1,1,3,3,7,7,9,9‐octamethyl‐5,10,11‐trithiadispiro[3.1.3.2]‐undecane‐2,8‐dione ( 19 ),102,2,8,8‐tetrachloro‐1,1,3,3,7,7,9,9‐octamethyl‐5,10,11‐trithiadispiro[3.1.3.2]undecane ( 20 ),11 and dispiro[adamantane‐2,3′‐(1,2,4)‐trithiolane‐5′,2″‐adamantane] ( 21 ) 12…”

Cleavage of macromolecular RAFT chain transfer agents by sodium azide during characterization by aqueous GPC

“…Although not demonstrated here, it does appear likely that all CTAs form a thiatriazole intermediate followed by a nitrile upon reaction with azide. The reaction of azide with dithiobenzoates 25 and compounds similar to xanthates 26 , dithiocarbamates 27 and trithiocarbonates 28,29 to produce corresponding (unstable) thiatriazoles has been reported.…”