Dibenzothiophene oxide

IGTS8 or simply IGTS8. The metabolic pathway in Rhodococcus sp. IGTS8 was delineated in the early 1990s [62], The pathway consists of four enzymes. DBT is converted to 2-hydroxybiphenyl (HBP) and sulfite via a 4-step pathway and the following intermediates DBT sulfoxide (dibenzothiophene-5-oxide, DBTO), DBT sulfone (dibenzothiophene-5,5-dioxide, DBT02) and hydroxyphenyl benzene sulfonate (phenol-phenyl sulfinate, HBPSi). 

A full iterative analysis of the more-complicated NMR spectra of both dibenzothiophene 5-oxide and 5,5-dioxide has been made. A slight broadening ( 0.05-0.1 Hz) of the lines associated with one of the protons in both compounds was assumed to be due to Jj 9 and this was used to assign peaks in the spectra. ... 

The binary system of 21a and 21b has been studied and compared with that of the open-chain analogs. Both 1,2,3,4-tetrahydrodibenzo-thiophene 5-oxide and octahydrodibenzothiophene 5,5-dioxide have been studied as engine oil lubricant additives, although the preparation of neither of these compoimds has been recorded. Dibenzothiophene 5-oxide (21a) is reported to he phytotoxic. ... 

Low-temperature chlorination of dibenzothiophene with elemental chlorine produces a chlorine adduct at the sulfur atom which is readily decomposed to dibenzothiophene 5-oxide. However, nuclear chlorination of dibenzothiophene has still not been studied. 2-Chlorodibenzo-thiophene has been prepared by the Sandmeyer reaction on 2-amino-dibenzothiophene and this route has now been extended to give... 

An unsuccessful attempt to repeat this reaction was made by Bird however, he was able to show that dibenzothiophene 5-oxide did, in fact, react with either thionyl chloride or phosphorus oxychloride to yield 2-chlorodibenzothiophene in good yield. Since all methods of nitration of dibenzothiophene yield a mixture of 2-nitrodibenzothio-phene and dibenzothiophene 5-oxide, which have identical melting points, it was concluded that the earlier workers had in fact been working with the sulfoxide and not the nitro compound. The reaction was rationalized as being a deoxygenative halogenation of a heterocyclic 5-oxide akin to the Meisenheimer reaction of A-oxides, which already had precedents in the sulfoxide field. Unfortunately the 2-chlorodibenzothiophene prepared by this route is contaminated with 2,8-dichlorodibenzothiophene which cannot be removed by crystallization. The best method of preparation of this compound is therefore via a Sandmeyer reaction on 2-aminodibenzothiophene. ... 

Dibenzothiophene 5-oxide is sufficiently nucleophilic to be alkylated at the oxygen atom by alkyl halides in the presence of silver perchlorate (96). Such compounds were found to be readily hydrolyzed back to the sulfoxide. The reaction of 96 with amines is discussed in Section VI, E, 3. 

Metallation of dibenzothiophene 5-oxide with three equivalents of butyllithium followed by carbonation gave a mixture of 4-dibenzo-thiophene carboxylic acid (36 /o) and dibenzothiophene (10%). The reduction or even elimination of sulfoxide groups in the presence of... 

Dibenzothiophene 5-oxide reacts with triaryltin chlorides to give complexes which show bacteriostatic and fungistatic properties, and a chromium tricarbonyl complex of dibenzothiophene has been described. ... 

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). 

Dibenzothiophene 5-oxide can be 0-alkylated the alkoxy group in the product can be displaced by nucleophiles (Scheme 189) however, l-methoxy-2,3-dibromobenzo[6]thio-phenium perchlorate regenerates the sulfoxide on treatment with piperidine (72JCS(Pl)899>. 

Dibenzothiophene undergoes surface-catalyzed oxidation when subjected to negative chemical ionization (NCI) with oxygen <93MI 209-02>. In the mass spectrum, the m/z ion at 184 initially attributed to M , is now shown to be the anion of 2-sulfobenzoic acid cyclic anhydride (68). Formation of (68) is presumed to arise by initial oxidation of dibenzothiophene to the sulfone (w/z 216) followed by oxidation of the angular carbon atoms to form the bicyclic intermediate (69) (w/z 248). Further attack by oxygen cleaves the ring to form (68) or (70) (Scheme 4). The mechanism has been proposed on the basis of further studies on the NCI(02) MS of dibenzothiophene-5-oxide, -5,5-dioxide, and also of various alkyldibenzothiophenes where similar patterns were observed. 

Several standard electrophilic reactions have been carried out on dibenzothiophene <85JHC215>. Nitration with cone. HNO3 and glacial acetic acid leads to a mixture (40% each) of 2-nitro-dibenzothiophene and dibenzothiophene-5-oxide. Nitration of the latter (fuming nitric acid and cone, sulfuric acid) gives 3-nitrodibenzothiophene-5-oxide, which could be deoxygenated to 3-nitrodibenzothiophene by 48% hydrobromic acid and glacial acetic acid. 

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