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Encyclopedia Britannica - Main :: COM-COR |
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CONH -- NH2. CO2R-> NH2CO NH CO2R; by the action of chlorcarbonic esters on urea (H. Schiff, Ann., 1896, 291, p. 367) ; and by the action of urethanes on urea chloride (L. Gattermann, Bee., 1888, 21, p. 293 R). They are readily decomposed by alkalis, yielding cyanuric acid and ammonia. Biuret (allophanamide), NH2CONHCONH2, is formed by heating urea; by the action of ammonia on allophanic ester; and by heating urea to 14o C. and passing chlorine into the melt at 14o-15o C. (J. Thiele, Ann., 1898, 303, p. 95 Anm.). It crystallizes in needles which melt at 19o C. (with decomposition), and is readily soluble in hot water. When heated strongly it is decomposed into ammonia and cyanuric acid. Baryta water hydrolyses it to carbon dioxide, ammonia and urea. With silver nitrate and caustic soda it yields a silver salt, Ag2C2HaN202 With nitric acid in the presence of sulphuric acid it yields a nitro derivative. Thiourea, or sulphocarbamide, CS(NH2)2, is formed by pro-longed fusion of ammonium thiocyanate (E. Reynolds, Ann., 1869, 15o, p. 224), by passing sulphuretted hydrogen into an ethereal solution of cyanamide
oxide
oxide
The alkyl derivatives of thiourea are obtained by the action of ammonia and of primary and secondary amines on the mustard oils (A. W. Hofmann, Ber., 1867, 1, p. 27): CSNR+NH3=NH2CSNHR; CSNR+NH2R=RNHCSNHR, or by heating the amide salts of the alkyl dithio-carbaminic acids, viz., NRCSS(NH,R). The monoalkyl derivatives are desulphurized by lead hydroxide in the presence of sodium carbonate, the a!3 dialkyl and trialkyl derivatives being unaffected (A. E. Dixon
Thiourea and many of its unsymmetrical derivatives have marked physiological action; thiourea causes a slowing of the pulse
Thiosemicarbazide, NH2.CSNH.NH2, prepared from hydrazine sulphate, potassium carbonate and thiocyanate (N. Freund, Ber., 1895, 28, p. 946; 1896, 29, p. 2501), crystallizes in long needles, which melt at 181-183 C. The addition of sodium nitrite to an aqueous solution of its hydrochloride converts it into amido-triaz- N- N sulphol S< 1. The hydrochloride with potassium cyanate C(NH2) : N gives hydrazothio-carbonamide, NH2.CO.NHNHCSNH2. Medicine
medicine
tissue . For this reason it is used to remove corneal opacities, deafness due to thickening of the membrane, stricture of the oesophagus and hypertrophy of the pylorus, it has also been successful in the treatment of adhesive parametritis. Fibrolysin is a modified form of thiosinamine made by mixing it with sodium salicylate Fibrolysin is freely soluble and may be given in hypodermic or intra-muscular injection. Like thiosinamine it has a specific action on scar tissue and has been used in urethral strictures. Both these preparations should only be used in cases where it is possible to exclude any tuberculous foci, or by their action in breaking down protective fibrous tissues they may cause a quiescent lesion to become active. In large doses toxic symptoms are produced, death following on coma.End of Article: CONH If you wish, you can link directly to this article.
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