Sulphonamides hydrolysis

C10H10N4O2S. White powder, which darkens on exposure to light m.p. 255-256 C. Prepared by condensing p-acet-amidobenzenesulphonyl chloride with 2-aminopyrimidine and subsequent hydrolysis. Soluble sulphadiazine is the sodium salt. Sulphadiazine is the least toxic of the more potent sulphonamides. ... 

Sulphonamides are most readily identified by hydrolysis with concentrated hydrochloric acid or with 80 per cent, sulphuric acid (for experimental details, see Section K.,7,12) ... 

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. 

Sulphonatnides. Sulphonamides are very resistant to the normal reagents for hydrolysis. Heating with 80 per cent, sulphuric acid at 160-170° results in rapid hydrolysis ... 

Hydrolysis of a sulphonamide. Mix 2 g. of the sulphonamide with 3-5 ml. of 80 per cent, sulphuric acid in a test-tube and place a thermometer in the mixture. Heat the test-tube, with frequent stirring by means of the thermometer, at 155-165° until the solid passes into solution (2-5 minutes). Allow the acid solution to cool and pour it into 25-30 ml. of water. Render the resulting solution alkaline with 20 per cent, sodium hydroxide solution in order to liberate the free amine. Two methods may be used for isolating the base. If the amine is volatile in steam, distil the alkaline solution and collect about 20 ml. of distillate extract the amine with ether, dry the ethereal solution with anhydrous potassium carbonate and distil off the solvent. If the amine is not appreciably steam-volatile, extract it from the alkaline solution with ether. The sulphonic acid (as sodium salt) in the residual solution may be identified as detailed under 13. 

Copper phthalocyanine derivatives are well established as turquoise blue direct and reactive dyes for cellulosic fibres. Chlorosulphonation at the 3-position, followed by hydrolysis, yields sulphonated direct dyes such as Cl Direct Blue 86 (5.32 X = H) and Blue 87 (5.32 X = S03Na). Solubility and dyeing properties can be varied by introducing four chlorosulphonyl groups, some of which are hydrolysed and some converted to sulphonamide by reaction with ammonia or alkylamines. This approach is also the main route to reactive dyes of the copper phthalocyanine type. The reactive system Z is linked to a 3-sulphonyl site... 

A. 6 Intramolecular nucleophilic catalysis of the hydrolysis of sulphonamides 238 B Reactions of the hydroxyl group 239... 

A.6 Intramolecular nucleophilic catalysis by the carboxyl group of the hydrolysis of sulphonamides ... 

Hydrolysis of sulphonamides, 1077 Hydroqumone diacetate, 664, 677 Hydroqumones, 749 Hydroxamic acid test for esters, 1062, 1063 ... 

Hydrolysis is a standard procedure for determining carboxamides. Alkaline hydrolysis yields ammonia or an amine which can usually be distilled out and easily detected or determined, e.g. by titration with acid. This method can be applied to sulphonamides, usually under rather more vigorous conditions359,360. Acid hydrolysis is also possible the solution can then be made alkaline and the ammonia or amine distilled and determined as after alkaline hydrolysis361. In another published work, the sulphonic acid product was isolated, e.g. by using an ion exchanger, and titrated with alkali362. 

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