the carbon atom, the formation of the two benzoyl derivatives of opposite activity becomes possible. I have elsewhere (B.A. Report, 1899, p. 685) contended, in the case of the sulphamic acid formed on sulphonating acetanilide, that when the isomeric change occurs, the ortho-acid is formed from the sulphamic acid if the sulpho-group be, as it were, let down gently; otherwise, the para-acid is produced.* This, perhaps, is true generally: in other words, it is only when the chlorine is "let down gently" from the chloramine that it enters into the ortho-position. If we seek to form a picture of the manner in which the equilibrium becomes disturbed, it may be supposed that when the change takes place and an atom of hydrogen becomes separated from the orthoposition in the nucleus, the "centric mechanism" momentarily breaks down and that in consequence the molecule either lapses or is on the point of lapsing into the ethenoid condition. At such a moment, hydrogen chloride might act in one of two ways, and either a chlorine atom might be introduced into the ortho-position, or a hydrogen atom might be restored to this position; in the latter case, two atoms of chlorine would be momentarily associated with the nitrogen, and would either escape as chlorine, or one might combine with a para-atom of hydrogen whilst another atom of chlorine took the place of the hydrogen atom thus removed. The three modes in which the chloramines undergo change are thus provided for. It is obvious that the character of the change might depend on the mass of hydrogen chloride present, and that it might also be affected by the solvent. Any alteration in the nucleus which diminishes the 'basic' properties of the nitrogen atom would necessarily exercise an influence in retarding the isomeric change, and alterations in the composition of the nucleus would also affect its stability and sensitiveness to change. It is therefore easy to understand that the behaviour of the various chloramines should be different. Important information as to the manner in which the isomeric * It may be here pointed out that the acetyl group exercises an important influence on the occurrence of this isomeric change. It is doubtful whether phenylsulphamic acid can be converted into the o-sulphonic acid; to convert it into p-sulphonic acid, it is necessary to heat it at about 180°. If, however, it be acetylated by merely heating it with acetic anhydride at 100°, and the product be poured into water and the solution boiled, sulphanilic acid is at once obtained. In the case of Bamberger's experiments, in which a solution of phenylsulphamic acid in acetic acid mixed with a few drops of sulphuric acid was kept for some time at 0°, it is probable that acetylation preceded the formation of o-sulphonic acid. It will be desirable to study the influence of different radicles on the occurrence of this isomeric change; although I have obtained the o-sulphonic acid from acetanilide, I have not hitherto succeeded in preparing it from benzanilide. change occurs will probably be obtained by determining the velocity with which change is effected under various conditions. It is proposed to undertake such experiments with chloramines when cool and dull weather sets in. The chloramines are an inviting subject of study for other reasons— and especially on account of their stability under some conditions and their instability under others. We are too much in the habit of regarding compounds as intrinsically unstable which probably are of a comparatively high order of stability in the absence of catalysts capable of determining their alteration; and the disregard of this circumstance has led to the assumption that isodynamic changes especially are the outcome of a state of intramolecular wobble. An increasing body of evidence tends to show that in the cases in contemplation, the process of change is of a complex character and largely extramolecular-in that it involves the co-operation of several distinct molecules and their units in a conducting system. CHEMICAL DEPARTMENT, CENTRAL TECHNICAL COLLEGE, EXHIBITION ROAD, S.W. XCIV.-Derivatives of Cyanocamphor and of Homocamphoric Acid. By ARTHUR LAPWORTH. It is now generally agreed that camphor must contain the complex CMe, CMe CO, but a divergence of opinion still exists with regard to the position of the last carbon atom making up the second ring. The recent work of Noyes and of Blanc on isolauronolic acid appears to -CMe have resulted in the establishment of the formula Me CH,CH,CCO,H for this substance, and would lead, in the absence of other data, to the belief that camphoric acid is a derivative of succinic acid, and that camphor itself contains a tetramethylene ring. Whilst it must be admitted that such an assumption serves to explain the whole behaviour of isolauronolic acid, it is easy to cite facts which are not in accordance with this view. In fact, no matter what formula for camphor may be chosen, it becomes necessary to assume that obscure changes of structure occur on certain occasions. Whilst, therefore, the Perkin-Bouveault formula offers a ready explanation of just those facts which do not appear to be in accordance with the Bredt formula, and vice versa, it may be asserted that the true formula for camphor is still unknown. The possibility of attacking the problem in an entirely new manner appeared during the study of camphononic acid (Lapworth and Chapman, Trans., 1899, 75, 989). This acid is a y-ketonic acid containing the above complex, and, as was pointed out at the time, probably contains the group >CO in the place of the >CH CO2H group of camphoric acid, so that, if this point could be definitely established, the inadequacy of any "succinic" formula for camphoric acid would be clearly demonstrated. One possible method of obtaining a solution of the problem was to prepare from camphor a compound containing the a-carbon atom united to the second nucleus by an ethylenic linking in this manner, ČO, as oxidation of this substance would probably afford the evidence required. It is well known, however, that the a-halogenated derivatives of camphor do not yield a compound of this type on treatment with bases. It was thought probable that this was on account of the strain which would result in a molecule so constituted, and experiments were therefore made with the object of preparing from camphor a derivative, corresponding with a-bromocamphor, but in which the brominated atom no longer formed part of a closed chain. The present paper contains an account of observations made during the attempt to obtain this preliminary compound. It was thought that a derivative of homocamphoric acid, CH<CO,H well as the most readily dealt with. Homocamphoric acid is obtained by hydrolysing a-cyanocamphor, which, being a B-ketonitrile, breaks down under the influence of alkali, in the same manner as the analogous B-ketonic acids, between the a- and B-carbon atoms, suffering simultaneous hydrolysis in accordance with the following scheme : (Haller, Dissertation, Nancy, 1879, 29). Much difficulty was at first experienced in obtaining cyanocamphor in sufficiently large quantity, but this was finally overcome by a modification of Bishop, Claisen, and Sinclair's method (Annalen, 1894, 281, 1351), namely, by the action of excess of hydroxylamine on hydroxymethylenecamphor. Having obtained cyanocamphor, the action of alkalis on its chloroand bromo-derivatives was examined, as it was expected that these would undergo hydrolysis in the same manner as cyanocamphor, affording chloro- or bromo-homocamphoric acid, thus, or at least the corresponding hydroxy-acid. It was found, however, that the first action was apparently the replacement of bromine by hydrogen, so that cyanocamphor is regenerated; this affords another example of the tendency of aa'-di-derivatives of camphor to undergo reduction under the influence of alkali. A further product was a crystalline acid substance having the formula C1,H,,O,N, probably the half-amide of homocamphoric acid, produced by hydrolysis, either preceding or following the reduction of the bromo-derivative. Experiments on the action of bromine on the nitrile of homocamphoric acid, CH, CN CO2H 19 3 C8H14 soon showed that no useful object was likely to be served by pursuing the inquiry in that direction. Finally, the behaviour of homocamphoric acid itself towards bromine was examined, but without any important result until the bromination was carried out in the manner detailed in the paper (p. 1063); even then, nothing crystalline could be isolated until nearly anhydrous formic acid was used as a solvent. Under these conditions, however, the monobromo-acid was finally obtained in a pure condition. a-Bromohomocamphoric acid behaves like homocamphoric acid itself, inasmuch as it exhibits no tendency to lose water and form an anhydride. It is somewhat readily soluble in benzene or chloroform, and in this respect differs from all the related acids, namely, camphoric, wand T-bromocamphoric, wr-dibromocamphoric, and homocamphoric acid itself, which are all nearly, or quite, insoluble in these liquids. Bromohomocamphoric acid does not yield an unsaturated acid on treatment with excess of alkali, but is converted into a salt of the corresponding hydroxy-acid. The latter does not exist in the free CH(CO,H)>0. Cam state, but changes to the lactonic acid, CH14 phanic acid is the name used for the corresponding derivative of camphoric acid, so that this substance may appropriately be termed homocamphanic acid. CO The behaviour of the diethyl ester of a-bromohomocamphoric acid towards organic bases was then investigated, and it was found that the action as a rule consisted for the most part in elimination of ethyl bromide from the molecule, and formation of the ethyl ester of homocamphanic acid, in accordance with the scheme On some occasions, a very small quantity of the ester of a highly insoluble dibasic acid, resembling homocamphoric acid, appeared to be produced, but much difficulty was experienced in increasing the yield of this substance. It was at last found, however, that by heating the bromo-ester with quinoline for a short time at 210°, and subjecting the product to treatment with strong alcoholic potash, a fairly good yield could be obtained. The new acid, thus produced, appears to be dehydrohomocamphoric acid, CH13 CO2H CH.CO2H. It readily absorbs bromine, becoming quite altered in properties, although no crystalline brominated products have as yet been isolated. Its solution in dilute sodium carbonate does not at once decolorise ice-cold potassium permanganate, but this is not the first unsaturated acid which has been found to behave in this manner. The potassium permanganate does attack the acid, however, and in the course of 24 hours or less, little or no dehydrohomocamphoric acid can be detected in the liquid. The products obtained by oxidising dehydrohomocamphoric acid in this way were carefully examined, and, as was anticipated, oxalic, camphoronic, and camphononic acids were the principal constituents. Camphononic acid itself was isolated by distilling some of the portion extracted with ether, and in order to make certain that the camphononic acid had not been formed during the heating, a second portion of the product was warmed with a little p-bromophenylhydrazine acetate, and a third with excess of a strongly alkaline hydroxylamine solution. In the former instance, nearly pure camphononic acid p-bromophenylhydrazone was deposited, and from the latter experiment the unmistakable oxime of camphononic acid was obtained in amount sufficient for complete examination and analysis. It is thus certain that dehydrohomocamphoric acid, on oxidation with cold dilute potassium permanganate, affords, for the most part, oxalic acid and camphononic acid, together with camphoronic acid, probably arising by further oxidation of the latter. Since camphononic acid is obtained by heating an open-chain tricarboxylic acid (Lapworth and Chapman, Trans., 1899, 75, 989) and yields camphoronic acid on oxidation, it can only be represented by one of the following formulæ : |