Thianthrene 5,10-dioxides

X-ray, 3, 947 <63AX310> trans-Thianthrene 5,10-dioxide dipole moment, 3, 947 <65JCS571)... 

Mislow and co-workers (232) have shown that the assignment of configuration in the series of diastereomeric cis- and rrans-thianthrene-5,10-dioxides 206 substituted in the aromatic ring is possible on the basis of UV or IR spectra. The authors cited found that the principal absorption band in the UV spectra of the trans isomer of 206 is shifted with respect to that of the cis isomer toward longer wave-... 

Dipole moment measurements of solutions of cis- (64BSF2119 65JCS571) and tru/ii-thianthrene 5,10-dioxide (65JCS571) and of thianthrene 5,5,10,10-tetroxide (65JCS57I) gave values of 1.86 and 1.70, 4.88, and 5.11 D, from which fold angles of 139°, 130°, and 140° respectively, were calculated. 

In 1,1,2,2-tetrachlorethane solution, the spectra of thianthrene and trans-thianthrene 5,10-dioxide are temperature independent for the cis-isomer, the lower-field resonance shifts further downfield with increasing temperature while the signals for 2-, 3-, 7-, and 8- protons remain constant over a 200° range. In chloroform, small, apparant temperature-dependent shifts for thianthrene, at all positions, were attributed to temperature-dependent shifts of the reference solvent signal. Using this, it was shown... 

Provided both stereoisomers are available, it is possible to use UV spectroscopy to differentiate cis- from trans -thianthrene 5,10-dioxides (see also Section II,D) a trans-isomer absorbs at longer wavelength, by 10 nm, than the corresponding cis-isomer, and the absorption peak is sharper (64JA2957). 

Conformational evidence of thianthrene, thianthrene 5-oxide, and as- and /ra r-thianthrene 5,10-dioxides has been reported by studing FI NMR spectra in different solvents (CD2CI2, toluene-r/g, THE-r/g THE = tetrahydrofuran) and at various temperatures (from 25 to —130°C) (see Section 8.12.4.3) <2005JOC3450>. 

H NMR spectra have established the interconversion barrier of /ra r-thianthrene 5,10-dioxides and confirmed that the conformational equilibrium of rfr-thianthrene 5,10-dioxides is strongly displaced toward the conformation with both sulfinyl groups in the pseudoequatorial position <2005JCX13450>. 

Computational studies showed that the nature of the reactive species in the oxidation of trimethylamine, iodide ion, and dimethyl sulfide with lumiflavin is a C4 a-hydroperoxide complexed with water. The other two species, C4 a-hydroperoxide and C4 a-peroxide, yielded higher activation energies.237 Kinetic and spectroscopic studies on the effect of basic solvents, ethers, esters, and amides, on the oxidation of thianthrene-5-oxide with substituted peroxybenzoic acids indicated the involvement of the basic solvent in the transition state of the reactions. A solvent parameter, Xtc, based on the ratio of the trans to the cis form of thianthrene-5,10-dioxide, has been introduced.238... 

Detailed assignments of the ESR spectra were not given, but from the number of lines obtained and from the widths of the spectra it is apparent that the electronic effect of the sulfinyl group depends upon its stereochemical orientation. Thus the anion-radical 184 of m-thianthrene-5,10-dioxide has a spectrum which resembles that of 183, whereas that of... 

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