Sodium toluene-p-sulphinate

Reduction of an arylsulphonyl chloride with zinc dust and water affords the zinc salt of the sulphinic acid, converted by sodium carbonate to the sodium salt, in which form it is conveniently isolated (e.g. sodium toluene-p-sulphinate, Expt 6.47) and thence by hydrochloric acid into the somewhat unstable sulphinic acid. 

Treatment of adenosine with sodium toluene-p-sulphinate and sodium hypochlorite gives a 50% yield of 2 -0-tosyladenosine. iV-Chloro intermediates are thought to be involved, which then give tosyl chloride by reaction with the sulphinate, but it is unclear why this procedure gives a higher yield than direct tosylation.229 Amino acids linked to (deoxy)-nucleosides via a sulphamoyl group have been reported they are structurally similar to the antibiotic ascamycin (see also Vol. 23, p.226).230 3. and 5 -0-dansyl derivatives of thymidine have been prepared, and shown to act as inhibitors of thymidine kinase from herpes simplex virus.231... 

The free sulphinic acid may be precipitated from a solution of the sodium salt in cold water by cautious acidification with hydrochloric acid. The toluene-p-sulphinic acid is filtered and sucked as dry as possible at the pump and dried rapidly between sheets of filter paper, m.p. 85 °C. 

The Eco2 reaction of 9-fluorenyl toluene-p-sulphonate with sodium hydroxide in 90% methanolic acetone has a primary kinetic hydrogen isotope effect of only 2.3 at 25°C . It is difficult to compare this result with that for the corresponding nitrate but if a transition state with considerable carbanion character is involved, then the indications are that nitrite is a better leaving group than toluene-p-sulphinate. It would be worth while to investigate the sulphur isotope effect for this latter reaction. 

A possible route to 2- and 3-t-aminophenothiazines is afforded by the reaction of chloro-lO-alkylphenothiazines with sodium or lithium derivatives of secondary amines. Thus, treatment of 1-chloro- or 2-chloro-lO-methylphenothiazine with sodium amide-morpholine leads to the same product, i.e. 2-morpholino-lO-methylphenothiazine, presumably by way of the same phenothiazyne intermediate (121). 3-Chloro- and 4-chloro-lO-methylphenothiazine react similarly giving, as expected, the same 3-mor-pholino-derivative via an analogous phenothiazyne intermediate. The phenazathionium cation (122), generated oxidatively in situ with ferric chloride, reacts readily with toluene-p-sulphinic acid, nitrite, or thiourea to... 

In chemically-cured materials, one example of an initiator/activator system is hydrogen peroxide as initiator, ascorbic acid as activator and cupric sulphate as co-activator. In light-cured materials, camphorquinone is used as a visible-light photochemical initiator, sodium p-toluene-sulphinate as activator and ethyl 4-dimethylaminobenzoate as photoaccelerator. 

The iodonium triflate (460 mg, 1 mmol) was added to a stirred slurry of anhydrous sodium p-toluene sulphinate (180 mg, 1.01 mmol) in dichloromethane (15 ml) at 20°C under nitrogen. After 15 min water (10 ml) was added and the phases were separated the aqueous layer was extracted with additional dichloromethane (2 x 5 ml), and the combined organic extracts were dried. The filtered solution was treated with hexanes (30 ml) and concentrated. The solid residue was purified by radial chromatography (silica gel, 200-400 mesh, dichloromethane-hexanes) to afford 3-tosyl-bicyclo[3.2.0]-3-heptene-2-one (197 mg, 75%), m.p. 164-165°C. The method is general for the preparation of sulphones with a cyclopentenone moiety other alkenyl iodonium salts gave alkynyl sulphones with sulphinates (Section 9.4.4). 

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