¹H and ¹³C NMR Spectral Study of Some 2r-Aryl-6c-phenylthian-4-ones, Their 1-Oxides and 1,1-Dioxides

Abstract

Four 2r-aryl-6c-phenylthian-4-ones 1bÀ1e and their 1-oxides 2bÀ2e and 1,1-dioxides 3bÀ3e have been newly synthesized. 1 H and 13 C NMR spectra have been recorded for all these compounds and 2r,6c-diphenylthian-4-one 1-oxide 2a. 13 C NMR spectrum has been recorded for the sulfone 3a of 1a. For selected compounds 1 H-1 H COSY, HSQC, HMBC, and NOESY spectra have been recorded. The vicinal proton-proton coupling constants suggest that in all these compounds, the heterocyclic ring adopts chair conformation with equatorial orientations of the aryl and phenyl groups. Proton and carbon chemical shifts suggest that in the sulfoxides, the S ¼ O bond is axial and enhances the J aa value by some special effect. The S ¼ O bond causes a significant upfield shift even on carbons without hydrogens. Significant solvent shifts also were observed.

1H and 13C NMR spectral study of some 3‐aryl‐5r‐aryl‐6t‐carbethoxycyclohex‐2‐enones—a study of four‐bond 1H1H couplings

“…Four‐bond coupling between 1,3‐diequatorial protons, which are in W conformation, has been well demonstrated 9–11. However, such couplings involving 1,3‐diaxial protons and 1,3‐equatorial–axial protons have not been demonstrated.…”

Chemoselective Synthesis and Anti-Kinetoplastidal Properties of 2,6-Diaryl-4H-tetrahydro-thiopyran-4-one S-Oxides: Their Interplay in a Cascade of Redox Reactions from Diarylideneacetones

“…NMR and LCMS analyses were fine for sulfoxide for both products. Further to previous studies [42][43][44], the NMR spectra of the major isomer agree The most stable configuration of the sulfoxide for this kind of heterocycle has been discussed in several studies [42,50,51]. According to these works, the axial position is surprisingly more stable than the equatorial one; the syn-cis is therefore expected to be the major isomer, if not the unique one.…”

“…In one case, it is in an equatorial position (hereafter quoted as anti-cis sulfoxide isomer), whereas in the other case, it is in an axial position (hereafter quoted as syn-cis sulfoxide isomer) (Figure 1). The most stable configuration of the sulfoxide for this kind of heterocycle has been discussed in several studies [42,50,51]. According to these works, the axial position is surprisingly more stable than the equatorial one; the syn-cis is therefore expected to be the major isomer, if not the unique one.…”