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Co. consists of a mixture of asclepiadin, asclepin, and asclepion; the latter has the composition C2H4O3; it melts at 104°, and is contained in Asclepias syriaca and in Vincetoxicum. The asclepiadin which is prepared by Parke, Davis, and Co., from Asclepias tuberosa, contains asclepin and a small quantity of a substance which has a tetanic action. G. H. M.

Conversion of Pyrroline into Pyridine-derivatives. By G. CIAMICIAN and P. SILBER (Ber., 20, 191-195).-Weidel has shown. (Abstr., 1886, 56) that Hofmann's bromopyridine, which is identical with that prepared synthetically from pyrroline, is a B-derivative; with a view to confirm this result and to determine the position of the carbon-atom introduced into the molecule when pyrroline is converted into halogenated pyridine-derivatives by the action of chloroform (Abstr., 1881, 826), bromoform (Abstr., 1882, 1214), or methylene iodide (Abstr., 1886, 367), the authors examined the action of benzal chloride on pyrroline. When these substances are heated with sodium ethoxide in molecular proportions at 160-170° for six hours, a non-basic substance, which has not been further examined, and phenylpyridine agreeing in all its properties with the B-compound prepared by Skraup (Abstr., 1883, 1013), are obtained. The introduced carbonatom therefore takes up the B-position in the pyridine molecule, the relationship between the bases being best expressed by the formulæ

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26 Dimethylpyridine Platinochloride. By T. LIWEH (Ber., 20, 66). A reinvestigation of the crystalline form of this salt has entirely confirmed Groth's statement (Abstr., 1886, 558) as to its isomorphism with picoline platinochloride. The following faces were observed: coPco, coP, coRco, OP, P∞, - 2P2, +2P2 (monoclinic).

Oxidation of Symmetrical Trialkylpyridines. By S. ALTAR (Annalen, 237, 182-201). The formation of lutidinemonocarboxylic acid from B-collidine has been described by Voigt (Abstr., 1885, 812). The acid is most readily purified by precipitation from an alcoholic solution by platinum chloride. The platinochloride,

(C,H,NO2)2,H,PtCl + 4EtOH,

crystallises in thick prisms, which effloresce on exposure to the air, and change in colour from deep red to orange. At the ordinary temperature, the salt loses 2 mols. alcohol; at 120°, all the alcohol is expelled, and the anhydrous salt melts at 221°. By decomposing an aqueous solution of the platinochloride with sulphuretted hydrogen, the hydrochloride, CH,NO2,HCl + H2O, is obtained in microscopic needles which are freely soluble in water. The free acid melts at 153°, and dissolves freely in water and alcohol; it crystallises with mol. H2O. All the salts of the acid are soluble. As lutidine monocarboxylic acid yields a-y-lutidine on distillation with lime, this acid may be regarded as a-y-dimethyl-picolinic acid.

Ethyl dihydroisopropyllutidinedicarboxylate yields ethyl lutidinedicarboxylate on oxidation, and also when the ethereal solution is treated with dry hydrogen chloride.

When oxidised with potassium permanganate, parvoline, C,NH2EtMe2, yields methylethylpyridinecarboxylic acid, C,NH,EtMe COOH. The platinochloride of this acid forms red crystals, which melt with decomposition at 194-195°.

The preparation of picolinedicarboxylic acid has been described by Voigt (loc. cit.). The crude product of the action of potassium permanganate on collidine is concentrated, and mixed with hydrochloric acid, when picolinedicarboxylic acid is slowly deposited. The precipitate is dissolved in ammonia and reprecipitated from the hot solution by hydrochloric acid. The pure acid melts at 274° with decomposition. It crystallises in slender needles, and is sparingly soluble in water. As picolinedicarboxylic acid is also formed by the oxidation of parvoline, the acid may be regarded as a-methyllutidinic acid, COOH C2NH2Me COOH. It is identical with Böttinger's uvitonic acid. W. C. W.

Quinolinedisulphonic Acid and its Derivatives. By W. LA COSTE and F. VALEUR (Ber., 20, 95-104).-The best method of formation of the mixture of ortho- and meta-quinolinesulphonic acids is to heat 1 part of quinoline with 34 parts of fuming sulphuric acid at 170°. The reaction is then complete in one hour. The acids are best separated by means of their mercury salts, that of the ortho-acid being easily soluble, that of the meta-acid insoluble, in cold water. The authors, differing from O. Fischer and Bedall (Abstr., 1882, 869), find the ortho-acid to be sparingly, the meta-acid easily soluble in

water.

The pure ortho-acid on sulphonation gives the same two disulphonic acids previously described by La Coste and Valeur (Abstr., 1886, 628). It is thus clear that the meta-acid yields only one disulphonic acid, and that this is identical with one of the two obtainable from the ortho-acid. The authors have examined some of the derivatives of a-quinolinedisulphonic acid. The potassium salt, C,NH. (SO,K)1⁄2 + 34H2O, crystallises in silky, white needles. a-Quinolinedicyanide, CNH (CN)2, was obtained by the dry distillation of a mixture of the above potassium salt and potassium cyanide. It crystallises in short, grey needles, insoluble in water, sparingly soluble in ether, benzene, and chloroform, readily so in acids and alkalis; it melts at 220 -222°. a-Quinolinedicarboxylic acid, C,NH,(COOH)2 + H2O, obtained by saponifying the dicyanide with soda, crystallises in needles which melt at 268-270°, and are soluble in alcohol, ether, chloroform, and boiling water. a-Hydroxyquinolinesulphonic acid (Abstr., 1884, 629) forms both normal salts and basic salts, in the latter, the phenolic hydrogen is also replaced. Both series of salts are crystalline, and mostly contain water of crystallisation; several of each series are described by the authors. Attempts to obtain oxidation products from this hydroxy-acid resulted almost uniformly in the total destruction of the compound, but in one case, with alkaline permanganate, a small quantity of a pyridinedicarboxylic acid was formed, which

seemed to be identical with the acid obtained by Hoogewerff and van Dorp by the oxidation of quinoline. L. T. T.

Quinoline-red. By A. W. HOFMANN (Ber., 20, 4-20).—This substance was patented by Jacobsen (Ber., 15, 2646), who obtained it by heating quinoline with benzotrichloride and zinc chloride at 120-130°; the zinc chloride may be omitted if a higher temperature is employed. The yield is only about 5 per cent. of the quinoline used. As the quinoline recovered from the manufacture gives scarcely any of the red dye when again treated in like manner, it seemed probable that some constituent of the crude quinoline was essential to the formation of the dye. Experiments were therefore made with quinaldine and with isoquinoline. With mixtures of quinaldine and quinoline (eq. mols.) a yield of only 1 per cent. of the red was obtained, but when isoquinoline was substituted for quinoline the yield rose to 9 to 12 per cent. The dye thus obtained, although showing very great resemblance to quinoline-red, yet differs from it in several particulars; the two, therefore, are possibly isomeric.

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Isoquinoline-red, C26H19N2C1, is obtained by heating quinaldine and isoquinoline (eq. mols.) with benzotrichloride and zinc chloride. The dye is formed far more readily than with quinoline. It crystallises in monosymmetric prisms, terminated by pyramids; a b c = 0.9783: 1:1-3651, ß = 54° 24'. By transmitted light, the crystals are deep crimson, in reflected light they appear reddish-brown with greenish-yellow, metallic lustre. It is soluble in water, alcohol, acetic acid, and phenol, insoluble in ether, carbon bisulphide, and benzene. The aqueous and alcoholic solutions are crimson with a strong yellowish-red fluorescence; the solutions dye wool and silk bright rose with some indication of yellow fluorescence; the colour is not fast. The dye prepared from quinoline crystallises invariably in slender needles, and in colour is pure red without metallic lustre; the solutions are crimson with a slight violet tint; the same violet tint is observable in wool or silk dyed with quinoline-red. The absorptive spectrum of both dyes in alcoholic solution consists of two bands in the green and bluish-green, but the bands of quinoline-red are narrower and more intense than those of isoquinoline-red. The platinochlorides, (C26H19N2Cl)2, PtCl, are obtained as scarcely crystalline precipitates, insoluble in water, alcohol, and hydrochloric acid; that from quinoline red is violet-red in colour, whilst the iso-compound is pure

crimson.

As no difference has as yet been detected in the chemical behaviour of the two modifications, the term quinoline-red refers to both in the reactions and derivatives described. When treated with zinc and hydrochloric acid, quinoline-red is quickly decolorised with formation of a leuco-base, which has, however, not yet been further investigated. When the reduction is effected by heating with alcoholic ammonium sulphide in sealed tubes for 8 to 10 hours at 200°, benzyl mercaptan and a new base of the formula C1HN2 are obtained. This base crystallises in plates of golden lustre, melts at 231°, and sublimes at a higher temperature without decomposition; it is insoluble in water, sparingly soluble in ether, benzene, and cold alcohol, more readily in

carbon bisulphide, and readily in phenol. It shows feeble basic properties; the hydrochloride crystallises in colourless needles.

When heated with hydrochloric acid or when oxidised, quinolinered yields benzaldehyde; as in the reaction with ammonium sulphide, the group introduced in the form of benzotrichloride is again eliminated.

When quinoline-red is distilled with zinc, a mixture is obtained from which a base, C1HN, was isolated. This is crystalline, melts at 86-86.5°, and yields a sparingly soluble crystalline platinochloride.

Reviewing the evidence deducible from the formation and reactions of quinoline-red, the author considers that it must be represented either by C,NH, CPhCl-C,NH,Me or by C,NH, CPhCl-CH2 C,NH, but there is not yet sufficient grounds to decide which of the two formule is correct. A. J. G.

Combination of Quinaldine with Formamide. By P. T. CLEVE (Ber., 20, 76).—When equivalent quantities of quinaldine and formamide are mixed together, a white crystalline mass, readily soluble in alcohol, ether, and chloroform, is at once obtained. The compound C,NH,Me C(OH) NH, forms radiating groups of needles, melts at 76°, and is decomposed by water; when heated in a sublimation apparatus, oily drops are obtained, which soon become crystalline.

W. P. W.

1, 3 Dimethylquinaldine and its Derivatives. By G. PANAJOTOW (Ber., 20, 32-42).-1, 3 Dimethylquinaldine, C,NH,Me, [Me3 = 2'12], is prepared by the condensation of metaxylidine with paraldehyde and concentrated hydrochloric acid. It crystallises in nearly colourless, monoclinic prisms or in small plates, melts at 146°, boils without decomposition at 260° under a pressure of 719 mm., and volatilises readily with steam. It has the characteristic odour of quinoline, is insoluble in water, readily soluble in alcohol, ether, and light petroleum. The sulphate, C12NH13, H2SO, + H2O, forms small, white needles; the hydrochloride, C12NH13, HCl, also crystallises in needles; the nitrate forms transparent, triclinic prisms; the platinochloride, (C12NH13)2, H2PtCle, crystallises in orange-yellow needles; the picrate forms long, yellow needles, melting at 185°. The methiodide, C12NH 13,MeI + H2O, crystallises in small, yellow needles.

Tetrahydrodimethylquinaldine, C12NH17, is formed by the reduction of the above base with tin and hydrochloric acid; it is an oil boiling between 200° and 250°, and, like tetrahydroquinaldine, gives the characteristic red colour when treated with dilute nitric acid; the platinochloride, (C12NH17) 2, H2PtCl6, forms orange-coloured plates.

Nitro-1, 3-dimethylquinaldine, C,NH,Me, NO2, is the only nitroderivative obtained in the nitration of the base; it forms long, white needles, melts at 92°, and is readily soluble in ether and chloroform. The platinochloride has the formula (C12H12N2O2)2, H2PtCl + 3H20. Amidodimethylquinaldine, C12NH12 NH2, obtained by reduction of the nitro-compound, crystallises in yellow plates.

1, 3 Dimethylquinaldinesulphonic acid, C,NH,Me, SO,H, prepared by the action of pyrosulphuric acid on the base, crystallises in small, yellow needles, and does not melt up to 260°. The barium salt crys

tallises with 3 mols. H2O in silky needles, sparingly soluble in water. In order to ascertain the position of the sulphonic group in this substance, the author endeavoured to synthesise a corresponding or identical acid by condensation from Jacobsen and Ledderboge's metaxylidinesulphonic acid (Abstr., 1883, 593); he finds, however, that no condensation occurs with paraldehyde. This unexpected result would seem to indicate that the constitution of this metaxylidinesulphonic acid is not that given by its discoverers [Me, SO,H: NH2 = 13:46], but that it is the 1: 35: 6 acid, as this latter constitution not only agrees with the non-formation of a quinaldine, but also brings the formation of the acid into the general rule that the sulphonic group when introduced into an aromatic amide does not assume the meta-position relatively to amidogen.

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Dimethylquinolinecarboxylic acid, C,NH,Me, COOH [Me2: COOH = 12' 3], is obtained by oxidation of 1: 3 dimethylquinaldine with chromic mixture. It crystallises in small, white needles, cannot be fused without decomposition, but can be sublimed in small quantity in long, lustrous needles; it is sparingly soluble in water and cold alcohol. The silver (with 1 mol. H2O) and barium salts are described. The platinochloride, (CHN COOH)2, H2PtCl + 4H,O, crystallises in orange-yellow needles; the picrate melts at 221°. When distilled with lime, it yields orthomethylquinaldine.

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Dimethylquinoline-a-acrylic acid, C,NH,Me, CH CH COOH = [1:3: 2']. When 1, 3 dimethylquinaldine is heated with dry chloral for eight hours on the water-bath, the condensation product C1H12NCI, + H2O is obtained in small, yellow needles, melting at 108°, and readily soluble in ether, alcohol, benzene, and hot light petroleum. This is boiled with aqueous potassium carbonate in a reflux apparatus for 15 hours, and the potassium salt formed, is neutralised with hydrochloric acid, when dimethylquinoline-a-acrylic acid separates. The latter crystallises in small, yellow needles, which decompose at 180°; the decomposition product melts at 210°. A. J. G.

Nomenclature of the Quinoxaline Series. By O. HINSBERG (Ber., 20, 21-23).—The author suggests that whilst the whole group

of substances containing the typical ring

N

should be termed

quinoxaline bases, it will be convenient to divide them into two subgroups. 1. The quinoxalines proper, in which only a single-ring group is combined with the nitrogen-ring, the names of the individual compounds being formed by adding the termination quinoxaline to the name of such ring group, for instance,

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