Thio sulphonic acids

Thio-sulphonic Acids.—Thio-sulphuric acid is related to sulphuric in having an oxygen of the latter replaced by sulphur. 

In exactly the same relationship stand the thio-sulphonic acids to the sulphonic acids. 

Salts of thio-sulphonic acids are also prepared by treating sulphon chlorides with metallic sidphides e.g. K2S. 

Sulphonic Acids.—When, however, an aliphatic mercaptan or thio- lcohol is oxidized we obtain a compound, containing a sulphuric acid residue, known as a sulphonic acid. 

The synthesis of 2-amino-2,6-dideoxy-D-glucopyranose-6-sulphonic acid, an analogue of a bacterial cell wall component, has been pre-pared via an acetylated 6-deoxy-6-thio compound. 

Oxidation from thiol through to sulphonic acid in one step can be accomplished by peracids [233], or activated H2O2 systems, including molybdates, tungstates [234] and ferrous salts [235] among the catalytic activators. Isethionic acid can be prepared from 2-thioethanol [236], and sulpho esters from thio esters [237]. 

The protection of certain functional groups, namely amide, cyanide, sulphonic acid, sulphonamide, AT-hydroxy, and thio-ether has not been discussed in previous chapters. Except for the amide group, very few studies have been made on the protection of these groups. The available information is summarized below. 

Ammonium salts of sulphonic acids 98. Sulphonic adds, sulphonamides 98. Amino-sulphonic acids 100. Sulphates of bases 101. Thioureas and thioamides 101. Sulphonyl halides 102. JV-Halosulphonamides 103. Aldehyde and ketone bisulphite compounds 103. Thiols 103. Thioethers 104. Thio-acids 104. Esters of sulphonic adds lOS. 

VIII. Compounds containing sulphur (with or without nitrogen and/or halogen). Ammonium salts of simple and substituted sulphonic acids. Sulphonic acids and their metallic salts sxdphonamides. Amino-sulphonic acids. Siilphates of bases. Thiourea, substituted thioureas, thioamides. Sulphonyl halides. iV-Halogeno-sulphonamides. Aldehyde and ketone bisulphite compounds. Thiols. Thio-ethers. Thio-adds. Esters of sulphonic adds. 

The neutral sulphur compounds include sulphides or thioethers, disulphides, sulphoxides and sulphones, sulphate and sulphonate esters, and isothiocyanates. Acidic sulphur compounds, i.e. sulphonic and sulphinic acids, thiols and thio-phenols, and the primary sulphonamides have already been discussed. The sulphates of amines are converted by aqueous sodium hydroxide into the free bases the sulphate anion can be detected in the resulting aqueous solution as barium sulphate in the usual manner. 

The disclosure of the potent activity of clavulanic acid has also led to the preparation of several structurally related compounds. " Thio-analogues of clavulanic acid have received some attention and the sulphone (162) is a powerful inhibitor of /3-lactamases produced by many pathogenic bacteria. 3-Carboxyisopenam sulphone (163) has been prepared in 4 steps from 4-iodomethylazetidinone. The sodium salt of the product was obtained by... 

To a solution of 0-01 mole of the thio-ether in the TninimuTn quantity of gjacial acetic acid, add a 3% aqueous solution of potassium permanganate (50% in excess of the theoretical). If the thio-ether precipitates during the reaction, add more acetic add to dissolve it. Pass sulphur dioxide into the reaction mixture imtil the predpitate of manganese dioxide has dissolved. Add crushed ice, collect the sulphone, and recrystaUize it from alcohol. 

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