Nitrogen sulphonamide

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

More recent work 8> shows that the S—N bond can be cleaved by hydroperoxides and that aromatic sulphonyl azides only undergo free radical thermal decomposition if a source of radicals is provided. Some light on the nature of the radical transfer agent has recently been shed by the observation 14> that dodecyl azides are formed (2.3%) in the thermolysis of mesitylene-2-sulphonyl azide (3) at 150 °C in w-dodecane under nitrogen. It seems likely that a dodecyl radical is produced by hydrogen abstraction by the triplet nitrene (5) [mesitylene-2-sulphonamide was also formed (1.1%)] which then attacks undecomposed sulphonyl azide... 

The hydrogen attached to nitrogen in sulphonamide is strongly addle due to the presence of strong electron withdrawing sulphonyl group. Hence, it is soluble in alkali. 

Oxidation of sulphonamides in the presence of bromide or iodide ions and sodium methoxide in methanol also leads to formation of the N-halogeno intermediate. The nitrogen-halogen bond in these intermediates is weak and will undergo themiolysis. At -10 °C, reaction proceeds by base catalysed elimination of hydrogen halide and ftirther steps lead to an a-amino acetal 20. The reaction is carried out in an undivided cell and renders a-aminoacetals readily available for the iso-... 

For further characterisation of oximes, imides and primary sulphonamides see p. 1226 under the miscellaneous neutral and acidic compounds containing nitrogen. 

In sulphonamides, the 33S chemical shift is sensitive to the electronic properties of both the a-group and of the substituent on the nitrogen atom.64 The replacement of both hydrogen atoms of the -NH2 moiety with methyl groups induces a downfield shift of 23 ppm, and the substitution of one hydrogen bond with another NH2 group causes a downfield shift of 18 ppm. 

Iodosylbenzene (1.1 g, 5 mmol) was stirred for 15 min in methanol (40 ml), under nitrogen. About 3 g of powdered Linde 3A molecular sieves were added (heated previously at 400°C and 0.01 torr for 15 h) and the suspension was stirred in a capped Schlenk tube for 2 h. The molecular sieves were removed and the drying process was repeated with a fresh portion of molecular sieves. A small loss of iodosylbenzene (44 mg) was indicated by iodometric titration. To the filtrate, after removal of the solid phase, was added the sulphonamide (1 g, 4.95 mmol) portionwise the solution turned yellow and a precipitate separated. After concentration to a small volume, dichloromethane (5 ml) was added and the solid mass was collected, washed with dichloromethane and dried affording [(2-nitrophenylsulpho-nylimino)iodo]benzene (1.8 g, 92%), as an amorphous powder, decomposing on heating. 

Lactam nitrogen aliphatic carbon Aromatic carbon-aromatic carbon Sulphonamide... 

In the previous sections we have discussed reactions in which the carbon-azide bond is formed by substitution on carbon of a preformed azide moiety or by its addition to various multiple bonds. Processes in which the azide nitrogen atoms are introduced in a stepwise manner are now considered. These syntheses include the reactions of diazo-nium salts with nucleophiles such as ammonia, chloramine, hydroxyl-amine, hydrazine, sulphonamides and azide ion. Recent work on... 

When j6-toluenesulphonyl azide was heated at 50-80° in isopropyl alcohol in the presence of diethyl peroxydicarbonate (20-3 azide 1 -4 peroxide), -toluenesulphonamide and acetone were obtained in 75 and 81% yields respectively " . It was thought that the 2-hydroxy-t-propyl radical (292) added to the azide to give 293 (equation 132) and that an intramolecular reduction and elimination of nitrogen occurred via a cyclic intermediate (294) to give the radical (295) and acetone. Hydrogen abstraction by (295) would then give the sulphonamide. 

This ring is formed when a 2-aminobenzenesuiphonamide, which carries an ethoxalyl group on the sulphonamide nitrogen, is treated with acetic anhydride. 

The rearrangement of an Af-arylsulphonamide, or an JV-arylsulphamide, to the isomeric aminoaryl sulphonyl compound (equation 43) is now a well-known reaction. The reaction is the nitrogen analogue of the Fries rearrangement (Section III.A.). For sulphonamides, acid-catalysed, base-catalysed, thermally promoted and photochemically promoted rearrangements have been observed for sulphamides, only the thermal and base-catalysed processes have been reported. 

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