Sulphonic anhydrides, cyclic

Trifluoroacetic anhydride is a most effective catalyst for the direct esterification of carboxylic acids by primary, secondary, and tertiary alcohols. Esterification proceeds under mild conditions via a mixed anhydride but is not successful with carboxylic acids of very low pKa and hydroxy acids when the reagent promotes lactonisation or polymerization [23, 24]. Dibasic acids may be esterified if they do not readily form cyclic anhydrides. Reagents such as trifluoromethane sulphonic anhydride [25], acetyl chloride [26], pyridine/p-toluene-sulphonyl chloride [27], sulphury chloride [28], thionyl chloride [29], and pyridine/phosphorus oxychloride [30] probably act in a similar way to trifluoracetic anhydride as reagents for direct esterification. 

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... 

In contrast to the usual reaction of aromatic aldehydes with cyclic ketones o-nitrobenzaldehyde condenses with 17-ketones to produce good yields of seco-acids, a reaction which has been applied to the preparation of 16-oxa-steroids. Thus, 3 -hydroxy-5a-androstan-17-one or its acetate affords the seco-steroid (153), which can be oxidised either as the free acid by ozone and alkaline hydrogen peroxide to the diacid (155) or, as its methyl ester (154), with chromium trioxide to the monomethyl ester (156). Diborane reduction of the diacid (155) or lithium aluminium hydride reduction of the dimethyl ester (157) gave the trans-diol (158), cyclised with toluene-p-sulphonic acid to 16-oxa-androstan-3)5-ol (159) or, by oxidation with Jones reagent to the lactone (152) (as 3-ketone) in quantitative yield. This lactone could also be obtained by lithium borohydride reduction of the monomethyl ester (156), whilst diborane reduction of (156) and cyclisation of the resulting (151) afforded the isomeric lactone (150). The diacid (155) reacted with acetic anhydride to afford exclusively the cis-anhydride (161) which was reduced directly with lithium aluminium hydride to the cis-lactone (160) or, as its derived dimethyl ester (162) to the cis-diol (163) which cyclised to 16-oxa-14)5-androstan-3) -ol (164). 

A nitrogen mustard derivative of barbituric acid has been reported without antitumour data [206]. 5-Diazobarbituric anhydride (XLVI) has been found to be amoebicidal at 0-001 mg/ml vs. Endamoeba histolytica [207]. The inhibition is reversed by nucleotides, but not by the bases or nucleosides. It had previously been found that (XLVI) is a cytosine antagonist in the yeasts, Torula utilis and Saccharomyces cerevisiae Hansen [208]. This compound is prepared by the action of nitrous and nitric acids on 5-aminouracil-6-sulphonic acid [209], and as a cyclic derivative of a barbituric acid, it has quite different properties from the pyrimidinetriones. 

In a related application the same authors have thermolysed the anhydride (239) to give the cyclic sulphone (240) which can be converted into the sulphone (241 X = O) with performic acid, (241 X = CHg) with diazomethane, or (241 X = NC02Et) with the azide NaC02Et. Elimination of SOa from the sulphones (241) results in the formation of the seven-membered rings (242). ... 

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