Dibenzothiophene-S-oxide

Dibenzothiophene S-oxide Dibenzothiophene S, S-dioxide Dibenzothiophene S, S-dioxide... 

Although single-electron-transfer (SET) processes would be expected to be important in reactions that use metals as reagents, this type of process has also been recognized in the reduction of carbonyl groups that involve 1,4-dihydronicotinamide derivatives . Recent work by Oae and coworkers" has shown that an SET process is operative in the reduction of dibenzothiophene S-oxide by l-benzyl-l,4-dihydronicotinamide when the reaction is catalyzed by metalloporphins. The reaction is outlined in equation (18), but the study gave results of much more mechanistic than synthetic value. This type of study is relevant to understanding biochemical mechanisms since it is known that methionine sulphoxide is reduced to methionine by NADPH when the reaction is catalyzed by an enzyme isolated from certain yeasts . 

Alkaline hydrolysis of S-salt 17 and mononitro S-salt 38 gave dibenzothiophene S-oxides S3 and 54, respectively (Eq. 14). But, dinitro S-salt 39 gave... 

Dibenzothiophene-S-oxide derivatives do not deoxygenate when photoirradiated under conditions used in this study. 

Although (7-sulfuranes had been postulated as reactive intermediates earlier, they had not been isolated <84CHEC-1(4)741>. The first stable pentacoordinated sulfur compound with four C—S bonds has now been synthesized and fully characterized <92ccii4i>. The 0-trimethylsilyl derivative (196) of dibenzothiophene S-oxide was treated at — 78 °C with 2,2 -dilithiobiphenyl. This led to (197) in 96 /o yield. The structure of (197) was fully secured by H and C NMR spectroscopy as well as by x-ray diffraction. In the solid state, it has a slightly distorted pseudotrigonal bipyramidal geometry with two apical S—C bonds, two equatorial S—C bonds, and the lone-pair electrons occupying the... 

The O-trimethylsilyl derivative (212) of dibenzothiophene 5-oxide on treatment at — 78°C with 2,2 -dilithiobiphenyl gave the first stable tetracoordinated sulfur compound with four C-S bonds (213) in 96% yield (92CC1141). 

In the synthetic area there have been a number of reports dealing with the photodeoxygenation of chalcogen oxides. Thus substituted dibenzothiopenes-S-oxides (62) undergo direct and sensitized photodeoxygenation at a rate which is not simply a function of the size of the substituents. The marked difference in the reactivity of the oxygenated dibenzothiophene dimers (63) and (64) was... 

Oxidation of thiophene with Fenton-like reagents produces 2-hydroxythiophene of which the 2(570 One isomer is the most stable (Eq. 1) <96JCR(S)242>. In contrast, methyltrioxorhenium (Vn) catalyzed hydrogen peroxide oxidation of thiophene and its derivatives forms first the sulfoxide and ultimately the sulfone derivatives <96107211>. Anodic oxidation of aminated dibenzothiophene produces stable radical cation salts <96BSF597>. Reduction of dihalothiophene at carbon cathodes produces the first example of an electrochemical halogen dance reaction (Eq. 2) <96JOC8074>. 

Kodama K, K Umehara, K Shikmizu, S Nakatani, Y Minoda, K Yamada (1973) Identification of microbial products from dibenzothiophene and its proposed oxidation pathway. Agric Biol Ghent 37 45-50. 

Resnick, S.M. and Gibson, D.T. Regio- and stereospecific oxidation of fluorine, dibenzofuran. and dibenzothiophene by... 

As described in Section IV.B, dibenzothiophenes, when substituted in positions adjacent to the sulfur atom, have reduced activity for direct sulfur extraction. As a result, catalysts that promote aromatic ring hydrogenation offer another route to desulfurization, as the partially hydrogenated ring presents much less steric restrictions to adsorption via r -S type bonding (17,21) or to oxidative addition to form a metallathiabenzene intermediate, as discussed in Section IV.E.3. In addition, the metal-S coordination bond strength is increased by increasing the electron density on sulfur, and the C-S bonds in hydrothiophenes are much weaker. 

Photodeoxygenation reaction was obtained also on dibenzothiophene oxide (01JOC4576 03JCR(S)60). 

Other Organosulfur Compounds. There have been reports of the microbial metabolism of other OSC. However, few of these studies have given the identities of intermediates or organic endproducts of the OSC. For example, aerobic cultures have been reported to remove sulfur from phenyl sulfide (62). Thioxanthene and thianthrene were transformed to water-soluble products by a dibenzothiophene-oxidizing bacterium (48). In addition, thianthrene and thioxanthene served as sole carbon sources for the aerobic thermophile S. acidocaldarius (69) which released sulfate from these compounds. 

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