Acids, carboxylic sulphinic

D. What Can We Now Say About Sulphonic Acid/Carboxylic Acid/Sulphinic Acid Analogies ... 

What does our analysis say about the sulphonic acid/carboxylic acid/sulphinic acid analogies enunciated in the beginning of this chapter What does our analysis tell us about the interplay of structure and energetics in the chemistry of sulphonic acids and their derivatives These questions remain unanswered. 

Oxidation of simple thietans with peroxy-acids gives monoxides and dioxides.However, oxidation of tetraphenyl-2-thietanone (89) with m-chloroperoxybenzoic acid gives (90), which is a stable carboxylic-sulphinic acid anhydride. Thietan dioxides are formed in the oxidation of thietans by NaMn04. 2-Arylsulphonyl-3-aryl-oxaziridines oxidize sulphides (including thietans) to sulphoxides. 3-Hydroxythietan can be oxidized to 3-thietanone, without oxidation at sulphur, with DMSO and benzoic anhydride. ... 

Alkyl dithioesters are produced in a facile one-pot reaction between carboxylic acids and -alkyl phosphorus sulphides, and the reagent (Et0)jP(0)CN converts sodium sulphinates into thiocyanates. ... 

Modifications of the 3-carboxyl group appear to be worth only in those cases where these derivatives are considered as precursors of the corresponding carboxylic acids [61], however precursors not always exhibit activity in vivo. Replacement of the 3-carboxyl group with acyl, ethoxycarbonyl, methoxycarbonyl and other acidic fragments (hydroxamic, acetic, phosphonic, sulphinic or sulpho) results in complete loss or diminishes dramatically antibacterial activity of these compounds. 

Metal oxides have been employed to catalyse the acylation of aromatics, leading to dimethylbenzophenones and 4-substituted benzophenones. The reaction of t-butylbenzene with benzoyl chloride in the presence of small amounts of ferric oxide leads to 4-t-butylbenzophenone. Substituted benzophenones have also been obtained by hydrolysis of the dilithium salts (68) formed by the reaction of lithium carboxylates with organolithium derivatives, and benzo-phenone-2 -methoxy-2-sulphinic acids (69) have been successfully prepared by displacement of the sulphone linkage in thioxanthen-9-one 10,10-dioxides (70)... 

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