Sulphinic acids, anhydrides

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. ... 

Sulphinic acid anhydrides (sulphonyl -1340 -7.46 vs w asym SO2 str, see refs 35 and 37... 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

Finally, aromatic sulphonic acids have been readily formed by the reaction of the corresponding sulphinic acid with benzeneseleninic acid (the selenium equivalent of a sulphinic acid) in a range of solvents, at low temperatures (equation 59)295. A selenosul-phonate is also formed. Benzeneseleninic anhydride [PhSe (0)0Se(0)Ph] may be used in the reaction in place of the seleninic acid. 

Chromones.- Enamines have previously been converted into chromones and in another approach, the enamine (104) reacted with thionyl chloride to give the chromone (105 n=2) in moderate yield. The sulphinic acid was readily oxidized to the sulphonic acid (105 n=3) by 3-chloroperoxybenzoic acid.110 A convenient synthesis has been described of 2-methylchromene-4-thione in 57% yield from 4-(2-hydroxyphenyl)butane-1,3-dione.111 The t-amino-methylchromones (106) have been synthesized and shown to be central nervous system depressants. A new synthesis of 2-substituted chromones (including flavones) uses 2-acetoxyphenacyl bromide (107) which is converted into its phosphorane (108). Heating this with an alkanoyl or aroyl chloride or anhydride in pyridine gave good yields of the chromone (109).113... 

The sulphinic acid that forms efficiently destroys the hydroperoxides and is able to repeatedly terminate oxidation chains by reacting with peroxide radicals. At higher temperatures sulphinic acid may also eliminate sulphurous-acid anhydride leading to the formation of sulphuric acid, which also effectively destroys hydroperoxides ... 

The pyridinesulphonic acids are normal in the derivatives which they form. Sodium and ammonium 3-cyano-4,6-dimethyl-2-sulphinate heated with copper and acetic anhydride, respectively, lost the sulphinate group . ... 

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