1126151-15-2

Upstream product

• 1126151-32-3 C₂₃H₁₉NOS 

Downstream Products

• 1228688-64-9 3,3-diphenyl-4(3H)-quinolone 
• 1228688-67-2 C₄₂H₃₀N₂O₂ 

Relevant academic research and scientific papers

Tandem 1,5-hydride shift/1,5-S,N-cyclization with ethylene extrusion of 1,3-oxathiolane-substituted ketenimines and carbodiimides. An experimental and computational study

Figure presented Under thermal activation in solution, N-[2-(1,3- oxathiolan-2-yl)]phenyl ketenimines and carbodiimides were converted into 2,1-benzisothiazol-3-ones bearing a pendant N-styryl or imidoyl fragment, respectively. These processes should occur with the concomitant formation of ethylene as result of the fragmentation of the 1,3-oxathiolane ring. The conversions of ketenimines took place under softer thermal conditions, toluene 110 °C, than those of carbodiimides, o-xylene 160 °C. A computational DFT study unveiled the mechanistic course of these transformations, rare tandem processes consisting of an initial 1,5-hydride shift of the acetalic hydrogen atom to the central carbon atom of the heterocumulene function leading to the respective o-azaxylylene. This transient intermediate then converts, in a single step, into ethylene and the experimentally isolated benzisothiazolone. This latter stage of the mechanism is rather peculiar, combining a 1,5-cyclization by S-N bond formation, aromaticity recovery at the benzene nucleus, and the fragmentation of the oxathiolane framework originating a new carbonyl group. It can be related with a vinylogous retro-ene reaction and shows pseudopericyclic characteristics. The computations also revealed that the alternative 6π electrocyclization of the transient o-azaxylylenes cannot compete, on kinetic and thermodynamic grounds, with the experimentally observed reaction channel. The two alternative reaction paths of a number of ketenimines and carbodiimides were computationally scrutinized, the results being in accord with the experimental outcomes. In addition, sulfur extrusion from the benzisothiazolones by the action of triphenylphosphine under two different reaction conditions led to three different types of heterocyclic products, 4(3H)-quinolones, quinolino[2,1-b]quinazolin-5,12-diones, and dibenzo[b,f][1,5]diazocin-6,12- diones, whose formation is explained by the initial formation of an intermediate imidoylketene. This reactive species could be trapped by a nucleophilic solvent, ethanol.

Unexpected formation of 2,1-benzisothiazol-3-ones from oxathiolano ketenimines: A rare tandem process

A rare one-pot reaction, a tandem [1,5]-H shift/1,5 electrocyclization/[3 + 2] cycloreversion process, leading from N-[2-(1,3-oxathiolan-2-yl)]phenyl ketenimines to 1-(β-styryl)-2,1-benzisothiazol-3-ones and ethylene, is disclosed and mechanistically unra