1,3‐Dipolar cycloaddition of dipolar reagents to bis(styryl) sulfones

Abstract

Sulfonyl bis pyrazolines and isoxazolines were prepared by 1,3-dipolar cycloaddition of nitrile imines and nitrile oxides to E,E-bis(styryl) sulfones.

Regioselective, One‐Pot, Three‐Component Synthesis of 1,3,4‐ and 1,3,5‐Triarylpyrazoles from 1‐ and 2‐Aryl‐1‐alkenyl Sulfones

“…In this paper, we report the regioselective onepot, three-component synthesis of 1,3,4-and 1,3,5-triarylpyrazoles from readily available starting materials: aryl aldehydes, aryl hydrazines, and 1-and 2-aryl-1-alkenyl sulfones (Scheme 1, b). As far as we could ascertain, only the Padmavathi group has reported the coupling of various alkenyl sulfones and hydrazones for the synthesis of sulfonyllinked bispyrazoles, [36][37][38][39][40][41][42] however, the elimination of the sulfonyl group has not yet been reported. Key to the success of this approach is whether the aryl sulfonyl group can act as a good leaving group, as was found to be the case for the nitro group.…”

Synthesis and Antioxidant Activity of Styrylsulfonylmethyl 1,3,4-Oxadiazoles, Pyrazolyl/Isoxazolyl-1,3,4-oxadiazoles

“…This may be due to more electron withdrawing effect of sulfonyl group. 30) The 1 H-NMR spectrum of 5a showed two doublets at δ 5.18 and 5.43 ppm due to C 4′ -H and C 5′ -H. Two singlets were observed at 5.20 and 4.89 ppm due to methylene protons attached to C-2 and C-5. The compound 5a displayed a broad singlet at 10.52 ppm due to NH which disappeared when D 2 O was added.…”

“…In the literature it was reported that the cycloaddition of 1,3-dipolar reagents to α,β-unsaturated systems proceeds in such a way that the electron rich atom of 1,3-dipolar species attacks β-carbon of α,β-unsaturated systems followed by isomerization. 29) In fact the cycloaddition of nitrile imine generated from benzaldehyde phenylhydrazone in the presence of chloramine-T to compound 3 proceeded regioselectively with the formation of 2-((arylaminosulfonyl)methyl)-5-((4′,5′-dihydro-1′,3′-diphenyl-5′-aryl-1′H-pyrazol-4′ylsulfonyl) methyl)-1,3,4-oxadiazole (4). The 1 H-NMR spectrum of 4a displayed two doublets at δ 5.10 (C 4′ -H), 5.34 (C 5′ -H) ppm, two singlets at 4.72 (CH 2 -(C-5)), 5.13 (CH 2 -(C-2)) ppm and a broad singlet at 10.47 ppm (NH).…”

Sequential Reduction and Dehydration of Phenacyl-(E)-Styryl Sulfones to Unsymmetrical (E,E)-Bis(styryl) Sulfones

“…While looking for pharmaceutically promising analogs of sulfones, and as part of our ongoing interest on styryl sulfones, we paid attention to the synthesis of unsymmetrical (E,E)-bis(styryl) sulfones. These compounds have been used as valuable precursors in the synthesis of various carbocyclic and heterocyclic systems such as cyclopropanes, 19 thiomorpholines, 20 dithiane-1,1dioxides, 21 pyrazolines, 22 isoxazoles, 23 1,4-substituted butadienes 24 and spiro heterocyclic systems. 25 Recently, bis(styrylsulfonyl) methanes and bis(styryl) sulfones have also been reported as potential HIV-1 integrase inhibitors 26 and anticancer agents, respectively.…”