Sulphamides

Both compounds are soluble in water and are readily hydrolysed to sulphamic acid, HjN S03" andammonia the hydrogen atoms are in each case replaceable by metals to form salts. Many derivatives of sulphamide and cyclic derivatives of sulphimide are known. 

Ionization equilibria of sulphamide, phenylsulphamide, mono-, di- and tri-substituted sulphamides have been considered and pK values have been determined145 for... 

When cyclic sulphamides (18 and 19) were studied148, it was found that the six-membered rings are more acidic than their acyclic analogues by ca 2.5 pKa units and that the five-membered cyclic sulphamides are ca 4 pK units more acidic than the model open-chain counterparts. 

Many other non-peptide inhibitors of HIV protease (dihydropyrone, cyclic urea and sulphamide series of compounds) were obtained by modifications of random screening leads. Examples of these include a cyclic sulph-one derivative 147 and 148 (PNU-140690) that showed activity against a variety of HIV t)rpe 1... 

This comprises a copolymer containing 72 to 95 wt.% of ethylene and 28 to 5 wt.% of vinyl acetate and a small amount of organic composite having a bactericidal action contained therein, which is composed mainly of N,N-dimethyl-N -phenyl-N -(fluorodichloromethylthio)sulphamide, 1,2-benzisothiazoline-3-on, diiodomethyl-p-tolylsulphone and methyl(benzimidazol-2-yl)carbamate. It is suitable as cushioning material for floors and walls and as a material for building blocks and babies toys. 

The nitration is carried out with a large excess of anhydrous nitric acid (10 parts of acid to 1 part of sulphamide). The product is precipitated by pouring the nitric acid solution into water. 

As will be seen by comparing the formulie of sulphuric acid, S02(OH)2, and sulphamide, S02(NH2)2, hydroxylamineisosulphonic acid is the amide corresponding with permonosulphuric acid, although it has not been directly prepared from this acid. In agreement with this relationship, however, hydroxylamineisosulphonic acid or amidopermonosulphuric acid possesses marked oxidising properties, readily liberating iodine from potassium iodide. 

Sulphamide, SOa(NH2)2, the amide of sulphuric acid, may be obtained by the action of dry ammonia upon a cooled solution of sulphury chloride in either ethylene chloride or chloroform solution 1... 

Another method of preparation for pure sulphamide is to dissolve the product of the reaction between sulphuryl chloride and liquid ammonia in a small quantity of water and acidify the solution in order to cause hydrolysis. After two or three days, when hydrolysis is complete, the mixture is evaporated to dryness in vacuo and the residue extracted with ethyl acetate. The sulphamide is dissolved out and on evaporating off the ethyl acetate, pure sulphamide is obtained.3... 

In the pure state, sulphamide is a non-electrolyte, indicating the weakness of its acidic tendencies. With the alkalis it forms salts, but not more than two atoms of hydrogen are displaceable by the metal.4... 

From a consideration of the electrical conductivities of its solutions it has been suggested1 that sulphamide may also exist in an aci form, thus ... 

Imidodisulphamide, NH2.S02.NH.S02.NH2, is the first product of the action of ammonium carbamate on pyrosulphuryl chloride.2 It is also obtained when sulphamide is heated nearly to its melting-point. Imidodisulphamide forms needle-shaped colourless crystals, melting at 160° C., and having a distinctly acid taste, since water causes rapid decomposition into sulphamide and amidosulphonic acid ... 

Sulphimide, or Trisulphimide, (S02NH)s.—This is formed together with ammonia and imidosulphonic acid when sulphamide is heated at 200° to 210° C. It is also formed in small quantity as the ammonium salt, together with sulphamide, when sulphuryl chloride is treated with ammonia in chloroform solution 4... 

According to A. Loir and C. Drion, when liquid ammonia at —65° is poured on to cone, sulphuric acid, the liquids do not mix, and a reaction gradually sets in. According to V. A. Jaquelain anhydrous ammonia reacts with sulphuric acid, forming sulphamide, and, according to A. Woronin, ammonium amidosulphate. 

Well-cooled sulphuryl chloride, diluted with 15-20 vols. of chloroform, is sat. with dry ammonia, the precipitated product dissolved in water, the soln. acidified with nitric acid, and the whole of the chlorine precipitated with silver nitrate the filtered soln. is neutralized with alkali, treated with silver nitrate, and the crystalline precipitate, which consists of silver sulphimide and some other silver derivative, separated by filtration. After adding a further quantity of silver nitrate, the clear soln. is treated with alkali, when silver sul-phamide is obtained as a colourless, amorphous precipitate, which, however, is invariably mixed with some other silver compound, probably the same as that present in the silver sulphimide precipitate. In order to remove this impurity, the well-washed precipitate is treated with hydrochloric acid in quantity exactly sufficient to convert the silver into chloride, and the strongly acid soln. is neutralized with ammonia and mixed with silver nitrate, when only the silver compound of unknown composition is precipitated pure silver sulphamide can now be precipitated by adding silver nitrate and excess of ammonia, and on decomposing this compound with the necessary quantity of hydrochloric acid, a neutral or feebly acid soln. of sulphamide is obtained. Sulphamide is deposited in large, colourless crystals when its aq. soln. is evaporated over sulphuric acid under reduced press. 

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