Dibenzothiophenes sulfonation

In dibenzothiophene-S,S-dioxide the S atom is in a ring, and hence more constrained. The yield of SOz in the radiolysis is linear with the dose to about 13 Mrad after which it levels off as in p,p -ditolyI sulfone. However, the yield of S02 in this case is much lower (a factor of 25) than in the case of p,p -ditolyl sulfone (G = 0.002 compared to G = 0.05). This stability of the dibenzothiophene sulfone could be partially due to back reaction to reform the parent sulfone and partially due to more efficient energy delocalization. The expected biphenylene product was not detected due to limitations of the analytical method. Bowmer and O Donnell70 studied the volatile products in y-radiolysis of dialkyl, alkyl aryl and diaryl sulfones. Table 2 gives the radiolytic yields of S02 and of the hydrocarbon products of the alkyl or aryl radicals. The hydrocarbon products are those obtained either by H atom abstraction or by radical combination. The authors69 suggested the mechanism... 

Constanti, M. Giralt, J., and Bordens, A., Degradation and Desulfurization of Dibenzothiophene Sulfone and Other Sulfur Compounds by Agrobacterium MC501 and a Mixed Culture. Enzyme and Microbial Technology, 1996. 19 pp. 214-219. 

Konishi, J. Ishii, Y. Onaka, T., et al., Purification and Characterization of Dibenzothiophene Sulfone Monooxygenase and FMN-Dependent NADH Oxidoreductase From the Thermophilic Bacterium Paenibacillus Sp Strain All-2. Journal of Bioscience and Bioengineering, 2000. 90(6) pp. 607-613. 

The Friedel-Crafts cyclization of biphenyl-2-sulfonyl chloride to give dibenzothiophene sulfone has been described (55%) ° however, thermal cyclization in octachloronaphthalene at 250°, under nitrogen, is reported to yield dibenzothiophene itself rather than the sulfone (47%). Reaction of biphenyl compounds with oleum (H2SO4 + SO3) to yield derivatives of dibenzothiophene 5,5-dioxide is widely used for the preparation of dyestuff intermediates (Section VI, E, 2). A typical example is shown in Eq. (3), starting from o-tolidine. ... 

When thianthrene 5,5,10-trioxide is exposed to butyllithium, via attack at the sulfoxide sulfur, dibenzothiophen sulfone and the diphenylsulfide diacid sulfone were the observed products, the latter predominating (Scheme 6) (57JA108). 

Another limitation of the method is that the reduction of the sulfones with UAIH4 occasionally does not regenerate the starting thiophene, as mentioned above. For example, benzo[b]thiophene sulfone is reduced with LiAlIfy in ether to the corresponding 2,3-dihydro compound (38.39). However, when 2-n-butyl benzo[b] thiophene sulfone was reduced with UAIH4 in ether, the starting thiophene was regenerated. Dibenzothiophene sulfone was also reduced to dibenzothiophene under these conditions. 

Inclusion of (/-orbital interactions made little improvement in the description of spin distribution in dithienothiophene sulfones " Urberg and Tenpas showed that the sulfone group in dibenzothiophene sulfone anion-radical could be regarded as exercising merely an inductive effect and not a mesomeric effect," although in earlier work Urberg and co-workers had... 

Here, the side product is dibenzothiophene sulfonic acid, which can be conveniently removed from the reaction mixture by extraction with aqueous base [30] (Scheme 2.158). 

Better understanding of the mechanism of biodesulfurization, as shown in Figure 8, may be gained from some recent studies ° Gallagher et al. reported a sulfur-specific pathway in microbial desulfurization of DBT. Rhodococcus rhodochrous strain IGTS8 metabolizes DBT in a sulflir-specific manner. Two routes of desulfurization have been identified. Under growth conditions, the intermediates are dibenzothiophene sulfoxide, dibenzothiophene sulfone, 2 -hydroxybipheny 1-2-sulfonate, and 2,2 -... 

Dibenzothiophene was converted to the corresponding bis(diphenyl-phosphinoyl)-dibenzothiophene sulfone in three steps, and to the... 

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