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to a crystalline mass melting at 18°. With ferric chloride, it gives a dark-red coloration showing a yellowish-red tinge; with phenylhydrazine, it forms a thick oil, and on treatment with aniline yields a liquid phenylimide; copper and zinc compounds were also obtained. Sulphuric acid dissolves the salt with a pale yellow colour, and on shaking the solution with ordinary benzene containing thiophen it gives an intense dark, red colour changing to violet-red. The acid has not been obtained pure, but is probably formed when the sodium compound of ethyl acetopyruvate is treated with water, and the product after treatment with a mineral acid is extracted with ether; this impure product is sparingly soluble in water, but cannot be crystallised from a hot solution, inasmuch as carbonic anhydride is evolved, and a crystalline compound, C,H12O6, obtained, which melts at 90-91°. W. P. W. Carbamide-derivatives of Dibromopyruvic Acid. By E. FISCHER (Annalen, 239, 185–194).—Dibromopyvureïd, CH2O2Br2N2, is deposited in colourless crystals when equal weights of carbamide and dibromopyruvic acid are heated at 100° with sulphuric acid. The compound is sparingly soluble in alcohol, water, and acids; it dissolves in alkalis, but it is rapidly decomposed on boiling the solution. Ammonia converts dibromopyvureid into a sparingly soluble ammonium salt, which slowly changes into dibromopyvuramide and ammonium oxalate. The quinidine salt is sparingly soluble in cold water. Tribromopyvurine, CH,Br,NO,, is prepared from dibromopyvureid by oxidation with nitric acid or by treatment with warm concentrated hydrobromic acid. It crystallises in colourless glistening plates soluble in hot alcohol, melts at 247° (uncorr.) with decomposition, and on treatment with ammonia splits up into bromoform and oxaluric acid. Dibromopyvuramide, C.H.Br2N,O2, melts between 170° and 180° with decomposition. It is soluble in hot water and in hot alcohol, but the aqueous solution is decomposed on boiling. Ammonia at 100° eliminates the bromine and forms an amorphous compound. A warm solution of baryta-water decomposes dibromopyvuramide, forming tartronic acid and small quantities of mesoxalic acid and amidouracil. W. C. W.

Sodium and Potassium Ethyl Tartrates. By LASSER-COHN (Ber., 20, 2003-2004).-Iodine has no action on sodium ethyl tartrate. When treated with bromine, ethyl tartrate and sodium bromide are formed. When potassium ethyl tartrate is treated with iodine dissolved in benzene, potassium iodide, iodoform, and a resinous substance are formed.

N. H. M.

Synthesis and Constitution of Uric Acid. By J. HORBACZEWSKI (Monatsh. Chem., 8, 201—207; comp. Abstr., 1883, 179; 1885, 1050). When trichlorolactamide (1 part) and carbamide (10 parts) are melted together in small quantities over a small flame, a brownishyellow mass is obtained, which when treated with potash, &c., as in the author's former method for the synthesis of uric acid (Abstr., 1883, 179) yields a white crystalline powder exhibiting all the properties, reactions, and the composition of uric acid. The yield of

uric acid by this method is not very good, this is accounted for by the partial decomposition of the acid when formed, and by the loss of the easily decomposable trichlorolactamide. This synthesis confirms the formula for uric acid suggested by Medicus, and shows it to be a NH−C−CO–NH

diureide of acrylic acid, CO<

NH_CO

NH-CNH–CO

G. H. M.

Solubility of Uric Acid. By C. BLAREZ and G. DENIGÉS (Compt. rend., 104, 1847-1849). The dissolved uric acid was estimated by means of potassium permanganate (this vol., p. 621).

The number of milligrams of uric acid dissolved by 100 grams of water at different temperatures is given by the equation

20·15t + 0.0020t2 + 0.000025ť3.

The following are some of the numbers actually observed :—

[blocks in formation]

The determinations are rendered difficult by the tendency of uric acid to form supersaturated solutions, and the formation of hydrated. products, which absorb variable amounts of permanganate. If the solution is heated to a high temperature and then cooled, the proportion of permanganate absorbed by the cooled liquid increases with the time of cooling. Constant results can only be obtained by agitating the uric acid with water at the particular temperature at which the determination of solubility is to be made, care being taken that contact is not too prolonged, especially at high temperatures.

C. H. B.

Synthesis of Compounds of the Uric Acid Series. By R. BEHREND (Annalen, 240, 1-23).—Nitromethyluracil, CH5N3O4, is prepared by gradually adding 4 grams of methyluracil to a mixture of 15 c.c. of fuming nitric acid and 15 c.c. of sulphuric acid. The temperature should not rise above 30-40°. The product is poured into water, and the crystalline precipitate recrystallised from water, from which it separates in prismatic crystals. It dissolves readily in hot water, sparingly in alcohol. Alkalis dissolve it with yellow colour. Potassium nitrouracilcarboxylate (Annalen, 229, 32) is prepared by adding methyluracil to a mixture of fuming nitric and sulphuric acids, previously heated at 80°. The carboxylic acid separates on cooling; this product is dissolved in 100 c.c. of water, and 15 grams of caustic potash added. The potassium salt separates on cooling in lustrous plates. When this is heated at 170°, it is converted into potassium nitrouracil, from which nitrouracil is obtained by treatment with hydrochloric acid.

Hydroxyxanthin is obtained by adding zinc to a solution of nitrouracil in hot dilute hydrochloric acid. When cold, it is filtered, neutralised with sodium carbonate, treated with a slight excess of potassium cyanate, and made acid with hydrochloric acid, when the hydroxyxanthin separates as a white crystalline precipitate.

Potassium nitrouracil, C,H,N,O,K+H,O, is prepared by neutralising a hot solution of nitrouracil with hydrogen potassium carboIt separates in pale yellow prisms. The ammonium salt forms. aggregates of prismatic crystals, and is sparingly soluble. The calcium salt (with 6 mols. H2O) forms large plates. The barium salt (with 5 mols. H2O) crystallises in long slender needles of a slightly silky lustre. The zinc (with 3 mols. H2O), copper (with 7 mols. H2O), and silver salts are also described.

CH(OH) NH,

Nitrobromohydroxyuracil, NO.CBr<CO.NH-COis formed when 10 grams of bromine is added to 6 grams of very finely powdered nitrouracil suspended in water and cooled with ice. After 24 hours, it is filtered, and the white precipitate washed with water and alcohol. It cannot be recrystallised, as it decomposes when warmed with water or alcohol. When distilled with steam, a brominated nitromethane and nitrouracil-carbamide, C,H,N,O,, are formed. The latter is also obtained by adding 1·5 gram of urea to a solution of 2 grams of nitrouracil in hot water. It is very sparingly soluble in water, and is decomposed by alkaline carbonates.

Amidouracilcarboxylic acid (Köhler, this vol., p. 128) is prepared by dissolving potassium nitrouracilcarboxylate in hot water, adding an alkaline solution of stannous chloride, filtering, and treating with hydrochloric acid. The yield is 80 per cent. of the theoretical.

Bromouracilcarboxylic acid, C ̧H ̧Ñ‚ВгО ̧ + 2H2O, is obtained by adding bromomethyluracil to fuming nitric acid so long as it dissolved readily. It crystallises from hot water in plates. It decomposes at above 170°. N. H. M.

Action of Phosphoric Sulphide on Ethyl Dimethylpyronedicarboxylate. By M. GUTHZEIT and W. EPSTEIN (Ber., 20, 21112113).—Ethyl thiodimethylpyronedicarboxylate,

C(COOEt) CMe.

CS C(COOEt) CMe

>0,

is obtained when ethyl dimethylpyronedicarboxylate (this vol., p. 502) is heated with phosphoric sulphide at 100° for half an hour. It crystallises in orange needles, melts at 109-110°, and is insoluble in water, readily soluble in ether, hot alcohol, and benzene. The salt does not give the thiophen-reactions with isatin and phenanthraqui none, and on treatment with aqueous baryta yields acetone and barium acetate, carbonate and sulphide, together with a small quantity of a sparingly soluble red barium salt containing sulphur, whilst ethyl thiophenyllutidinedicarboxylate, CH2O,SN, is formed when it is treated with aniline in acetic acid solution. This crystallises in slender yellow needles, melts at 245°, dissolves in alcohol, and is identical with the compound obtained by the action of phosphoric sulphide on ethyl phenyllutidinedicarboxylate.

Lutidone when heated at about 160° with phosphoric sulphide yields thiolutidine, C,H,SN; this crystallises in needles, begins to fuse at 205°, melts at 210-215°, and is readily soluble in hot water and alcohol, insoluble in ether. W. P. W.

Thiophen-group. By N. ZELINSKY (Ber., 20, 2017-2025).— Metathioren, C.SH,Me, [Me, = 2: 4], is obtained by distilling a mixture of 20 grams of a-methyllevulinic acid (Bischoff, Annalen, 206, 319) and 30 to 35 grams of phosphorus trisulphide in a capacious retort. The fraction boiling below 160° is boiled for some hours with caustic potash, dried with calcium chloride, and distilled. It is a clear, colourless, strongly refractive oil, having an odour of petroleum. It boils at 137-138° (corr.); sp. gr. at 20° = 09956. The yield of pure product is 20 per cent. of the weight of the a-methyllevulinic acid. It shows the same colour reactions as thiophen. The acetyl-derivative, CASH Me,Ac, is prepared by adding a mixture of 6 grams of metathioxen, 6 grams of acetic chloride, and 15 grams of light petroleum to 20 grams of light petroleum containing 8 grams of aluminium chloride in suspension. The whole is heated for a short time on a water-bath, the petroleum poured off, and the residue treated with cold water and steam-distilled. It is a clear liquid, boiling at 226— 228° (uncorr.), has an odour of acetophenone, and becomes dark when exposed to air. It gives a red coloration with sulphuric acid and isatin. The hydroxylamine-derivative of the acetyl compound, CHSNO, crystallises from aqueous alcohol in thick needles melting at about 70°; the phenylhydrazine-derivative, C1HSN, forms bright yellow needles melting at 70°.

Methylthiophencarboxylic acid, C,SH,Me COOH [Me: COOH = 2:4 or 4: 2], is obtained, together with thiophendicarboxylic acid, by oxidising 1 gram of thioxen in a solution of 12 grams of sodium hydroxide, and 57 grams of potassium permanganate in 800 c.c. of water. After two days, the product is steam-distilled, and the distillate extracted with ether. It crystallises in needles melting at 118– 119°, dissolves readily in ether, sparingly in water, and can be sublimed. The calcium sult, with 24 mols. H2O, crystallises in plates.

=

Thiophendicarboxylic acid, C.SH(COOH), [(COOH), 2: 4], is formed only in small quantity in the above experiment, and is prepared by oxidising the monocarboxylic acid; a portion of the latter always remains unattacked. It is readily soluble in hot water, and does not distil with steam; when heated at 280°, it sublimes with partial decomposition. The silver salt forms a curdy precipitate; the methyl salt crystallises in small plates and melts at 120-121°; the ethyl salt forms an oil which gradually crystallises, and melts then at 35-36°. When 5 grams of carbamic chloride is added to 3 grams of B-thiotolen dissolved in 10 grams of carbon bisulphide, the whole gradually treated with 5 grams of finely-powdered aluminium chloride, and then warmed on a water-bath, an amide is obtained which crystallises from hot water in needles melting at 119°. When the amide is saponified with alcoholic potash solution, the potassium salt of an acid melting at 143° is obtained, probably identical with Levi's y-thiotolenic acid (Abstr., 1886, 540). When oxidised, this acid yields a dicarboxylic acid which is not identical with that described above; it shows the fluoresceïn reaction, and is therefore probably an orthoderivative.

Dimethyllevulinic acid and trimethylthiophen were also prepared, but are not described. N. H. M.

VOL. LII.

3 զ

Molecule of Crystalline Benzene. By A. SCHRAUF (Ann. Phys. Chem. 31, 540-543).-Thomsen supposes that the arrangement of atoms is such that they lie in pairs of CH at the six corners of an octahedron. This arrangement does not accord with the fact discovered by Groth, that crystals of benzene belong to the trimetric system and are double refracting. These conditions may be satisfied in the simplest manner by removing two atoms H,H at opposite corners, and placing them one at each of two other opposite corners of the octahedron. This arrangement is shown to give the correct ratio of the axes. C. S.

Constitution of the Hydrocarbons CHan from Caucasian Petroleum. By W. MARKOWNIKOFF and J. SPADY (Ber., 20, 1850— 1853). The authors have examined the fraction boiling at 118-120°, and giving analytical results and vapour-density corresponding with the formula CH16. Potassium permanganate did not cause oxidation either in acid or neutral solutions. When the hydrocarbon was boiled with sulphur, hydrogen sulphide was evolved, and small quantities of a heavy oil containing sulphur were formed, but the main liquid still boiled at 118-123°. When treated with a mixture of nitric and sulphuric acid, this liquid yielded a small quantity of trinitrometaxylene, whilst much of the original oil was recovered. The authors, therefore, consider that this petroleum fraction is, or contains, hexahydroxylene. When shaken successively with large quantities of sulphuric acid, metaxylene-mono- and di-sulphonic acids appear to be formed.

L. T. T.

Influence of Light and Temperature on Chlorination. By H. GAUTIER (Compt. rend., 104, 1714-1716).-Schramm has recently shown that the substitution of chlorine in the side-chains of benzene hydrocarbons can be effected even at 0°, provided the reaction takes place in sunlight. The author has made experiments in order to ascertain how far the laws of chlorination hold good for compounds other than hydrocarbons.

When a current of chlorine is passed into acetophenone at the ordinary temperature, substitution takes place rapidly with development of heat. The product is a dichloro-derivative with the chlorine exclusively in the methyl-group. If a slow current of the gas is passed into cooled acetophenone in diffused daylight, substitution still takes place almost exclusively in the side-chain, the yield of a derivative with chlorine in the nucleus amounting only to about 1 per cent. The result is the same in complete darkness, the temperature of the liquid exerting no influence.

Since the development of heat is mainly due to the formation of the monochlorine-derivative, the latter was treated with chlorine both in daylight and in the dark. The result was still the same.

It is evident that in this case light has no influence on the nature of the substitution. It does, however, accelerate the change, which requires four times as long in the dark as in diffused daylight. It would seem as if the presence of an electronegative group tends to prevent the introduction of an element of the same nature.

During the winter, dichloracetophenone (this vol., p. 141) was ob

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