2 0.2190 gave 0.3163 CO2 and 0.0710 H2O. C=39.38; H=3.60. 0.2234 0.3155 CO2 0.0750 H2O. C=38.51; H=3.70. 0.2130 49.5 c.c. moist nitrogen at 15° and 750 mm. N = 26.83. CH2ON, requires C = 38·71; H=3·22; N=27·09 per cent. 3 The solution of the acid in ammonia gives a gelatinous silver salt. The acid, like its ester, has basic properties, dissolving in hot concentrated hydrochloric acid, and from the solution, on cooling, colourless crystals of the hydrochloride separate out. This salt, however, is unstable, and loses hydrochloric acid, not only at 100°, but even at the ordinary temperature. The same ester is obtained from guanidine by using ethyl chlorofumarate instead of ethyl acetylenedicarboxylate, and this is, indeed, a preferable method of preparing the substance. Its identity with ethyl hydroxyaminopyrimidinecarboxylate was verified by a direct comparison of their properties and by the following nitrogen determination : 0.206 gave 40.5 c.c. moist nitrogen at 13° and 756 mm. N = 23.1. CH2ON requires N = 22.95 per cent. Action of Benzamidine on the Ethyl Esters of Acetylenedicarboxylic and Chlorofumaric Acids. Formation of Glyoxaline Red, C18H12O2N4. The interesting behaviour of benzamidine towards ethyl phenylpropiolate, which yields, according to the temperature at which the reaction is allowed to proceed, either benzalglyoxalidone or diphenylpyrimidone, induced us to study the reaction of benzamidine, on the one hand with ethyl acetylenedicarboxylate, and on the other with ethyl chlorofumarate. We have found that the same compound results from either ester. The reaction is effected by mixing alcoholic solutions of sodium ethoxide and benzamidine hydrochloride, and gradually adding ethyl acetylenedicarboxylate or ethyl chlorofumarate. The mixture, which first turns yellow and finally becomes dark red, is allowed to stand for a day; water and a little acetic acid are then added, and the red solid collected. This is insoluble in water, but dissolves, although with great difficulty, in a large amount of boiling alcohol, and, on cooling, gradually separates out in ruby-red crystals. The yield is unsatisfactory, this being partly due to the circumstance that reduction accompanies the formation of the substance. The compound dissolves in alkali, yielding a red solution, and therefore has acidic properties. The following analytical data were obtained: 0.3024 gave 0.7550 CO, and 0·1092 H2O. C=68·08; H=4·0. 0.1550 0.3888 CO2 0.0598 H,O. C=68.41; H= 4.27. 28 c.c. moist nitrogen at 13° and 772 mm. N=17·40 C18H12O2N4 requires C=68.35; H=3.80; N=17·72 per cent. 0.1933 On boiling with glacial acetic acid, glyoxaline red suffers a remarkable change; it enters into solution and, on cooling, yellowish needles separate out, which decompose at 262°. The analytical results obtained with different specimens proves the substance to have the composition C18H14O3N4, which differs from that of glyoxaline red by the elements of 1 mol. H2O. 0.5330 CO2 0.0875 H2O. C=64·55; H=4·30. C-64.30; H=4-27. 0.1490 21.5 c.c. moist nitrogen at 20° and 757 mm. N = 16·43. 0.1982 0.2144 3 C= C18H14ON, requires C = 64.67; H=419; N=1676 per cent. The close relation of this compound to the red product follows, not only from its mode of formation, but also from the fact that its yellow solution in dilute potash quickly changes on standing to reddish-violet the colour of the alkaline solution of glyoxaline red. An attempt to support the constitutional formulæ of both substances (p. 806) by means of their behaviour towards boiling caustic potash has furnished the following result. The solution darkens, and an evolution of ammonia takes place, which ceases after about an hour's heating. The alkaline liquid is freed by filtration from a small quantity of a brown precipitate, then acidified with hydrochloric acid and extracted with ether. This dissolves out a solid which we have identified as benzoic acid. Besides this acid and ammonia, there is also formed oxalic acid. These decomposition products agree with the formulæ of the compounds given in the introduction, but it is obvious that further experiments are desirable before the formulæ can be regarded as conclusively established. GONVILLE AND CAIUS COLLEGE, LXXIII.-Bromination of Benzeneazophenol. Part II. By JOHN THEODORE HEWITT and WILLIAM GEORGE ASTON. IT has been recently shown by the authors that when benzeneazophenol is brominated in a glacial acetic acid solution containing excess of fused sodium acetate, two bromine atoms enter the phenol nucleus in the ortho-position relatively to the hydroxyl group (Trans., 1900, 77, 712). In the absence of sodium acetate, a bromo-derivative of unknown constitution was obtained, the investigation of which forms the subject of the present communication. p-Bromobenzeneazodibromophenol. When benzeneazophenol is dissolved in five times its weight of glacial acetic acid and treated with one molecular proportion of bromine, only a portion of the azophenol is attacked, for on pouring into water, collecting the precipitate, and recrystallising it a few times from glacial acetic acid, a compound is isolated which is sparingly soluble in cold acetic acid and melts at 143–145° (uncorr.). The various preparations were found to contain a percentage of bromine corresponding with that required for the formula C12H2ON,Bг. Experiments were then made on the bromination of benzeneazophenol suspended in water, molecular proportions being again employed, but the same brominated product was obtained, although, owing to the reaction not having proceeded so smoothly as in acetic acid solution, the melting point was generally a degree or two lower. Finally, it was found that a satisfactory yield of the substance might be obtained by the following procedure. Ten grams of finely powdered benzeneazophenol are suspended in 50 grams of glacial acetic acid, the mixture being well cooled by ice, and stirred while 25 grams of bromine diluted with 25 grams of glacial acetic acid are gradually added. The bromine is used up rapidly, and only a trace of it can be detected at the end of the operation if the above quantities are employed. The product is poured into water, the precipitate collected, washed, and recrystallised from glacial acetic acid. The brownishorange needles so obtained were analysed with the following result: 0.1743 gave 0.2125 CO2 and 0.0331 H2O. C=33·25; H=2·11. 0.1924 02489 AgBr. Br=55:04. 0.2603 15.6 c.c. moist nitrogen at 18° and 766 mm. N=7·27. C12HON,Br, requires C = 33·10; H=1·63; Br=55·14; N = 6·45 percent. 12 The substance melts at 148° (corr.), and dissolves in acetone, ethyl alcohol, ethyl acetate, benzene or its homologues, aniline or nitrobenzene; it is less soluble in cold glacial acetic acid, and dissolves very sparingly in light petroleum. On treatment with concentrated sulphuric acid, the substance yields a dark red sulphate of the corresponding quinonehydrazone, the azophenol separating as a yellow precipitate on the addition of water. Conclusive evidence in favour of the view that the substance is p-bromobenzeneazodibromophenol was obtained by brominating p-bromobenzeneazophenol in presence of sodium acetate, and benzeneazo-o-dibromophenol in presence of strong sulphuric acid. The same substance was obtained in both cases, and proved to be identical with the product obtained by the direct action of bromine on benzene azophenol; each preparation causing no depression of the melting point of the others. Bromination of Benzeneazodibromophenol.-Twenty-four grams of benzeneazodibromophenol were suspended in 290 grams of glacial acetic acid mixed with 24 grams of concentrated sulphuric acid, and to the well cooled mixture, 11 grams of bromine, diluted with 44 grams of glacial acetic acid, were slowly added. The product was recrystallised from acetone, and melted at 148°. Bromination of p-Bromobenzeneazophenol.-13 grams of p-bromobenzeneazophenol were dissolved in 50 grams of acetic acid together with 1.3 grams of fused sodium acetate. The solution was well cooled, and 1.5 grams of bromine in 4 grams of acetic acid added. The product, after recrystallisation, melted at 148°. The production of p-bromobenzeneazo-o-dibromophenol can be shown diagrammatically as follows: acetic acid solution. Br The acetyl derivative was obtained by boiling p-bromobenzeneazodibromophenol for 1 hour with an equal weight of fused sodium acetate and three times its weight of acetic anhydride. It separates from glacial acetic acid in very small crystals, but in larger, orange prisms from chloroform in which it is easily soluble. The melting point is 167°. 0.1460 gave 0.1883 CO2 and 0·0359 H2O. C-35·17; H=1·97. C14H2ON,Br, requires C = 35·22; H=1.89 per cent. 9 2 2 3 The compound is very soluble in carbon disulphide and moderately so in aniline, benzene, toluene, nitrobenzene, ethyl ether, ethyl acetate, or ethyl benzoate, but dissolves only sparingly in cold acetone, amyl or ethyl alcohol, or light petroleum. The benzoyl derivative was prepared by boiling the azophenol for 1 hour with 2 times its weight of benzoyl chloride, and was recrystallised from a large excess of spirit, in which, even at the boiling point, it is but very sparingly soluble. It forms brownish-orange needles melting at 129°. 0.2188 gave 134 c.c. moist nitrogen at 16° and 750 mm. C19H11ON,Br, requires N = 5.21 per cent. 2 N = 6.00. The substance is taken up sparingly by acetic acid, ethyl alcohol, or petroleum spirit; it is fairly easily soluble in carbon disulphide, benzene or its homologues, or aniline, whilst in the remaining organic solvents its solubility is moderate. The ethyl ester was obtained by heating 5 grams of the azophenol with 0.7 gram of caustic potash, 1.6 grams of ethyl bromide, and about 50 c.c. of absolute alcohol in a sealed tube for 1 hours at 105-110°. After cooling, the contents of the tube were warmed on the water-bath with dilute caustic soda, the insoluble ethyl ether collected, washed, dried, and recrystallised from benzene. Beautiful, golden needles melting at 125° were obtained, which were very soluble in carbon disulphide and dissolved fairly easily in ether, ethyl benzoate, or hydrocarbon solvents. The solubility in acetone, ethyl alcohol, or amyl alcohol was slight. 2 0.1027 gave 0.1361 CO2 and 0.0203 H2O. C=36·14; H=2.20. CHON,Br, requires C=36-28; H=2.40 per cent. Tribromobenzeneazophenol.—As it seemed at one time possible that the substance obtained by the direct action of bromine on benzeneazophenol might be tribromobenzeneazophenol, the latter was synthetically prepared by coupling diazotised tribromoaniline with phenol. The only azo-compound derived from tribromoaniline, so far as the authors know, is the tribromobenzeneazodimethylaniline described by Silberstein (J. pr. Chem., 1883, [ii], 27, 113). Since Silberstein's method of diazotising tribromoaniline is rather tedious, the process we adopted may be described, as it is simple. 13.2 grams of finely powdered tribromoaniline were dissolved in 15 c.c. of concentrated sulphuric acid, a finely divided precipitate of the base or its sulphate being obtained by the addition of 5 c.c. of water. The well-cooled mixture was diazotised by adding 2.8 grams of pure, solid sodium nitrite in small portions at a time, left for 2 hours, and then poured on to crushed ice. Ten minutes later, the solution was added to 4 grams of phenol and 40 grams of sodium carbonate, (Na,CO,,H,O), dissolved in 300 c.c. of water and cooled to - 1o. The precipitated azo-compound was collected, washed, and extracted with hot dilute caustic potash solution, the filtrate precipitated by hydrochloric acid and the azophenol recrystallised from glacial acetic acid. Small, bright, orange prisms were obtained melting at 168.5°. 0.2627 gave 0.3229 CO, and 0.0382 H2O. C-33.41; H=1.68. C12HON,Br, requires C = 33·10; H=1.63 per cent. 3 Tribromobenzeneazophenol is easily soluble in acetone or ethyl acetate, dissolves fairly well in ethyl alcohol, ethyl ether, acetic acid, or benzene, but is only very sparingly soluble in light petroleum. For |