the constitution represented in the formula COOH·C(OH)2 CH, COOH (which would follow from the formula adopted for maleïc acid), on the ground that it does not react with phenylhydrazine, and further that the ethyl salt of inactive tartaric is very different in its behaviour to Wislicenus's ethyl oxalacetate, COOEt CO CH2 COOEt. Ethyl oxalacetate boils at 120°, and the ethyl salt of inactive tartaric acid at 156° (both under 14 mm. pressure). The latter salt still contains two hydroxyl-groups, and when saponified with lime-water yields the characteristic calcium salt of inactive tartaric acid.

The only alternative formula for inactive tartaric acid is one in which two alcoholic hydroxyl-groups are represented as attached to two different carbon-atoms. The formation of an acid having this formula by the oxidation of maleic acid, gives no support to the formula COOH C·CH, COOH for the latter compound.

Having in view the observations of Brühl (Abstr., 1887, 1005) on the molecular refraction of aldehyde and paraldehyde, the author points out that differences in the molecular refraction of the ethyl salts of fumaric, maleïc, mesaconic and citraconic acids (Knops Inaug. Diss., Bonn, 1887) harmonise with the formule for these compounds which he supports (compare also Abstr., 1887, 916). N. H. M.

Oxidation of Diallyloxalic Acid. By P. BULITSCH (J. Russ. Chem. Soc., 1887, 73-97).-The action of oxidising agents on diallyloxalic acid was investigated by Saytzeff and Schatzky, but formic, carbonic, and oxalic acids were the only products obtained. From the analogy of this acid to dimethyloxalic, diethyloxalic, and diisopropyloxalic acids, it might be inferred that on oxidation a ketone would first be formed, which would subsequently split up into acids with a lower number of carbon-atoms than the original acid. It also seemed desirable to ascertain whether citric acid is formed in the reaction, as was supposed by Schatzky.

In order to study the products of the limited oxidation of diallyloxalic acid, it was treated with very dilute nitric acid. For this purpose diallyloxalic acid (10 grams) was acted on by a mixture of nitric acid (65 grams) of sp. gr. 1155 with an equal quantity of water, at as low a temperature as possible. When the action was complete, the greater part of the nitric acid was expelled by careful evaporation, and after removing the oxalic acid by means of barium carbonate, the filtrate was boiled with a strong solution of baryta. On cooling, a yellow barium salt separated; this, after being washed, was dissolved in aqueous acetic acid, precipitated hot with lead acetate, and the precipitate decomposed with hydrogen sulphide. The filtrate was concentrated and a mixture of alcohol and ether added to remove inorganic impurities. On evaporating the clear solution, a brownish or yellow syrup was obtained, which did not solidify at -20°, and could not be distilled with aqueous vapour without decomposition. It is insoluble in ether, chloroform, and carbon bisulphide, but easily soluble in alcohol or water. It reduces Fehling's solution on warming, but this may be due to some admixture; silver salts, however, are not reduced. Its reaction is feebly acid. Repeated analyses

14

point to the formula C,HO6, and its constitution, that of tetrahydroxyoctolactone, may be represented by the formula

·CH(CH2OH)·CH.

C>C(OH).CH2-CH(OH)·CH2OH.

Of the metallic derivatives, the potassium, sodium, ammonium, lead and silver salts, could not be obtained in a state fit for investigation. By the action of barium or calcium carbonate at the ordinary temperature, the corresponding derivatives were obtained in the form of amorphous, gummy masses, which are easily powdered when dry. After drying in the desiccator, the derivatives have the formula (CHO)2Ba and (CH1507)1⁄2Ca, whereas on drying at 100° they lose 2 mols. H2O, becoming (CHO)2Ba and (CH3O6), Ca respectively. The constitution of the salts, dried at the ordinary temperature, is represented (where baBa), by the formula

[OH CH2 CH(OH)·CH2]2°C(OH)·COOba,

12

the salt of a pentahydroxy-acid. After drying at 100°, the salt is only soluble in water with great difficulty, and no longer takes up the elements of water. On boiling the tetrahydroxyoctolactone with calcium or barium carbonates, basic salts are obtained, which, when dried in the desiccator, have the formulæ CH16O,Ba and CHO,Ca, and after drying at 100° become C,H12OBа and C,H12O6Ca. The loss of 2 mols. H2O is analogous to that mentioned in the first instance. When the lactone is boiled with aqueous baryta, a still more basic salt is obtained, having the formula C.H15O.ba, (dried in the desiccator) and CHO,ba, (dried at 100°). The calcium salt prepared in an analogous manner is, however, identical with that obtained with calcium carbonate (see above). The original lactone could be easily regenerated from the basic barium salt by transforming it into the lead salt, and decomposing the latter with hydrogen sulphide. Cold water is without action on tetrahydroxyoctolactone, but warm water dissolves it and the corresponding pentahydroxydipropylacetic acid seems to be formed. The lactone does not unite with iodine or hydrochloric acid, this being in accordance with the saturated character of the compound. The most careful oxidation with a very weak solution of potassium permanganate in alkaline solution (1 per cent.) yielded carbonic and oxalic acids only. B. B.

Action of Sulphuric Acid on Diallyloxalic Acid. By P. BULITSCH (J. Russ. Chem. Soc., 1887, 97-106).-In order to study the hydration of diallyloxalic acid, and to compare the product. obtained with tetrahydroxyoctolactone, the former was treated with sulphuric acid. For this purpose, sulphuric acid of 66° B. is added drop by drop to diallyloxalic acid cooled with snow, when the mixture becomes brown, and some gas is evolved. The reaction is accelerated by warming the mixture gently from time to time, and cooling again immediately.

After addition of water, the liquid is boiled and saturated with barium hydroxide; the filtrate from the barium sulphate is then extracted with ether, which on evaporation leaves an oily liquid; this

is a mixture of a saturated with an unsaturated lactone, the latter being more easily soluble in ether than the former. In order to separate the two, the product obtained as above is boiled with water, and the unsaturated lactone taken up from the solution by extracting it twice (not more) with ether. After removing sulphuric acid from the aqueous solution by means of baryta and the excess of the latter by carbonic anhydride, the filtrate is concentrated by evaporation, and decomposed with sulphuric acid. The filtrate from the barium sulphate is again extracted with ether. The remaining liquid, containing the saturated lactone, is neutralised with lead carbonate, filtered, and after separating the lead in solution by hydrogen sulphide and precipitating the mineral salts with alcohol and ether, the saturated lactone is obtained. Its composition is C,H404. It is a syrupy liquid, soluble in alcohol and ether, and having a feebly acid reaction, a bitter taste, and an agreeable odour, especially on gently warming. It does not reduce Fehling's solution. It forms an amorphous bariumderivative, (C.H1505)2Ba, which does not lose water at 120°, and is the salt of a trihydroxy-acid.

The formula of the unsaturated lactone (which is much more soluble in ether than the saturated compound) is C,H2O3, and it forms a barium-derivative, (C,H13O4)2 Ba, not losing water at 120°, and a corresponding calcium-derivative. The saturated lactone is a dihydroxylactone, the unsaturated a monohydroxylactone.

When the saturated lactone, C.HO, the product of hydration of diallyloxalic acid, is subjected to a further treatment with sulphuric acid, a dehydration takes place, the unsaturated lactone, CH12O3, being formed. The supposed structure of the lactones in question was confirmed by Hübel's test. B. B.

Mucohydroxybromic and Mucohydroxychloric Acids. By H. B. HILL and A. W. PALMER (Amer. Chem. J., 9, 147-174).-Reference is made to former work (Abstr., 1879, 224; 1884, 731; 1885, 531) on the decomposition of mucobromic acid by baryta and by potassium phenoxide. The constitution of the mucohydroxybromic and mucohydroxychloric acids is represented by the formula

COOH-C(OH):CX·COH,

their bibasic characters being due to the environment of the hydroxylgroup; the aniline-derivatives are represented by the formula COOH C(OH):CX CH:NPh, that is, as analogous to Böttinger's anilglyoxylic acid (Abstr., 1879, 51).

Mucohydroxybromic acid, CH,BrO4, is best obtained from mucobromic acid by very cautious treatment with baryta at a low temperature (yield 60 per cent.). The free acid is obtained by mixing the equivalent of sulphuric acid with the powdered barium salt, and evaporating in a vacuum. It is crystalline, melts at 111-112°, and its solution decomposes readily. The barium salt, BaC,HBrO, + 2H2O, is sparingly soluble in water, and decomposes readily when heated; an acid salt could not be obtained. The potassium salt, KC,HBrO + H2O, and the silver salt, Ag2CHBrO4, are described, as well as the

dimethyl, diethyl, and monethyl salts, C,H,BrO, Et, only the last was obtained in crystals; it melts at 88-89°.

When the barium salt is boiled with baryta-water, carbonic, oxalic, formic, and hydrobromic acids are formed, together with an acid yielding a gummy barium salt.

The oxidation of mucohydroxybromic acid is best effected by bromine-water; oxalic acid, bromal hydrate, and hydrobromic acid are formed.

With phenylhydrazine or hydroxylamine, no definite compound with mucohydroxybromic acid could be obtained, but with the primary aromatic amines and carbamide crystalline condensation-products are readily formed.

Anilmucohydroxybromic acid, C,H,BrO, NPh, is most readily obtained by dissolving barium mucohydroxybromate in hydrochloric acid and adding aniline hydrochloride; it crystallises in pale-yellow needles, sparingly soluble in cold water, and melts at 131-132°. The salts Ba(CH,BгNO3)2 + H2O, K2C10HBгNO3, Ag2CH, BrNO1, and a monobasic silver salt, are described; they are yellow and crystalline. With phenylhydrazine a crystalline compound,

C10H,BrNO3, CH,N2,

10

is. formed without elimination of water; it is very readily decomposed.

Mucohydroxychloric acid, C,H,CIO,.-It has been previously shown that when treated with baryta, mucochloric acid yields a-p-dichloracrylic and formic acids, but it is now shown that by adding the baryta only as fast as it is acted on, and at a low temperature, 73 per cent. of the theoretical yield of barium mucohydroxychloric acid is obtained, along with some a-B-dichloracrylic acid. The free acid is obtained like the corresponding bromine compound; it is, however, more stable, and melts at 114-115°. The barium salt, BаC,HCIO, + 2H2O, on keeping, changes to a more stable form, containing only 1 mol. H2O; the potassium and silver salts are anhydrous; the monethyl salt is crystalline, melting at 94-95°; but the diethyl salt is a viscous liquid. The barium salt, when heated with excess of baryta-water, is decomposed in just the same way as the mucohydroxybromic acid; there is no simple relation between the quantities of oxalic and carbonic acids formed. Bromine-water also decomposes the acid, just as it does the bromo-acid.

Anilmucohydroxychloric acid, C,H,CIO, NPh, is obtained in like manner to the corresponding bromine-compound; it contains 1 mol. H2O, which is readily given off over sulphuric acid, or at 100°; it is brilliant yellow, and melts with decomposition at 145-147°. The three salts, Ba(CH,CINO3)2 + H2O, Ag:C10HCINO3, and K,CH,CINO3, are described. With phenylhydrazine it forms a compound,

C10H CINO3 CH.N2,

readily decomposed by acids or alkalis.

H. B.

Murexoïn. By O. BRUNN (Ber., 20, 513-518).-Murexoïn (Rochleder, J. pr. Chem., 51, 405) is prepared as follows:-Caffeine

is converted by Fischer's method (Abstr., 1882, 217) into dimethylalloxan, which is reduced by hydrogen sulphide to tetramethylalloxantin. This is finely powdered, and in portions of 5 grams moistened and spread on a plate, and exposed to the action of air and ammonia until the whole acquires a dark-brown colour. The murexoïn is afterwards crystallised from hot water; the yield is almost quantitative. It is rather sparingly soluble in water with an intense colour resembling that of potassium permanganate, crystallises in slender prisms, and sublimes at about 230° without decomposition. When evaporated down with dilute bydrochloric acid, it decomposes into dimethylparabanic acid and another compound which could not be purified. N. H. M.

Vapour-density of Aluminium Ethide. By L. Roux and E. LOUISE (Compt. rend., 106, 73-75).—The aluminium ethide was obtained by the action of mercuric ethide on aluminium in sealed tubes; it boiled at 195-200°. The vapour-density was determined by Meyer's method in an atmosphere of pure and dry nitrogen, the apparatus being heated by different liquids of known boiling points. The following results were obtained :

Temperature.....
Vapour-density...

:

It is evident that near its boiling point the vapour-density is normal, but at a higher temperature the compound dissociates, and the density is reduced to one-third. Most probably the compound splits up in accordance with the equation Al,Et,= 2A1Et, + CH10.

C. H. B. Condensation of Furfuraldehyde with Chloraldehyde. By P. MEHNE (Ber., 21, 423-428).-Chlorofurfuracraldehyde,

CH2O CHICCI CHO,

is prepared by slowly adding 10 per cent. aqueous soda to mixed aqueous solutions of furfuraldehyde and chloracetaldehyde. It crystallises in broad, yellow, lustrous needles, melts at 79°, is soluble in hot water, ether, alcohol, benzene, light petroleum, and chloroform, and can be distilled with steam. The phenylhydrazine-derivative forms golden-yellow plates, begins to decompose at 142°, and melts at 157°. The oxime crystallises in small, white, interlaced needles, begins to sublime with decomposition at about 110°, and melts at 164-165°.

y-Chlorofurfuracrylic acid, CHO-CH:CCI-COOH, is prepared by heating the aldehyde with moist silver oxide for some days in a reflux apparatus; it crystallises in tufts of white needles, melts at about 142°, but sinters at a lower temperature. It is soluble in water, alcohol, ether, benzene, and chloroform, insoluble in light petroleum. 7-Chlorofurfurpentic acid, CH,O CH.CCI.CH.CH COOH, is prepared by heating to boiling 4 parts of y-chlorofurfuracraldehyde, 3 parts of anhydrous sodium acetate, and 5 parts of acetic anhydride, for three hours in a reflux apparatus. It forms clear yellow, interlaced needles, melts at 168°, and is soluble in alcohol, ether, benzene, 2 h

VOL. LIV.