Sulphur-containing Rings

Last year an interesting ring-expansion process was described in which benzo-thiazepinone derivatives were formed from benzothiapyranones. This process has now been extended to embrace the isoelectronic sulphenium methylides 

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Rings containing Sulphur. - The subject of a lecture given in 1980 and published in 1981 was some aspects of the chemistry of episulphoxides. ... 

Cycloadditions involving unsaturated five- and six-membered rings containing sulphur have offered convenient routes to thiolan and thian derivatives. 3-Thiabicyclo[3,l,0]hexane 3,3-dioxide (27a) and its 2-methyl-and cij -2,4-dimethyl-derivatives (27b) and (27c) have been synthesized from the appropriate thiolen 1,1-dioxides by cycloaddition of diazomethane... 

Four-membered Rings containing Sulphur and Oxygen... 

Four-membered Rings containing Sulphur, Nitrogen, and Phosphorus.— The compound (160) results from the reaction of (155 R=p-anisyl) and (McjSOjNMe. Heterocycle (161) is obtained from isocyanates and (162). Thionyl chloride reacts with (163) to give (164). ... 

Crystallisable polymers have also been prepared from diphenylol compounds containing sulphur or oxygen atoms or both between the aromatic rings. Of these the polycarbonates from di-(4-hydroxyphenyl)ether and from di-(4-hydroxy-phenyl)sulphide crystallise sufficiently to form opaque products. Both materials are insoluble in the usual solvents. The diphenyl sulphide polymer also has excellent resistance to hydrolysing agents and very low water absorption. Schnell" quotes a water absorption of only 0.09% for a sample at 90% relative humidity and 250°C. Both the sulphide and ether polymers have melting ranges of about 220-240°C. The di-(4-hydroxyphenyl)sulphoxide and the di-(4-hydroxy-phenyl)sulphone yield hydrolysable polymers but whereas the polymer from the former is soluble in common solvents the latter is insoluble. 

The thiazole ring system is found in many types of dye. Thiazole-containing sulphur dyes and primuline were considered in section 6.4-2. Quaternised dehydrothio-p-toluidine 6.133 is available as Cl Basic Yellow 1 (6.152). Other derivatives of this intermediate are used as direct dyes, such as Cl Direct Yellow 8 (4-58). The benzothiazole ring appears in various azo disperse dyes [14], quatemisation of which gives useful cationic dyes, an important example being Cl Basic Blue 41 (4.99). Another example containing a quaternised thiazole ring is Cl Basic Red 29 (4-102). 

It is known that four-membered rings containing phosphorus or sulphur are formed more readily than those containing only first-row elements, and the EM s calculated for compounds A.6.1 and 2 allow a quantitative estimate of the importance of the effect. In this series the four-membered ring is formed almost as efficiently as the five [the EM for the hydrolysis of H02C(CH2)j SOjNMePh (A.6.3) is 2 x 107 M]... 

N.m.r. data have also been used to show that the compound (C6H6PS)3 has the heterocyclophosphane structure with a five-membered P3S2 ring containing isolated sulphur atoms. One of the directly connected phosphorus atoms is linked to another sulphur atom in an exo-position, in addition to the phenyl group. The above structure has also been confirmed by a second study. ... 

PART II Six-Membered Rings containing Oxygen or Sulphur by G. P. Ellis... 

Thehydroxybenzofuranderivative,5-hydroxy-2-oxo-3-phenyl-2,3-dihydrobenzo-furan underwent 2-alkylation and ring closure with 4-(2-n-butoxyethoxy)mandelic acid in acetic acid at 110°C containing sulphuric acid during 9 hours, followed by oxidation by the addition of ammonium persulphate with further reaction at 110°Cfor 1 hour (ref.72). 

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