HH

N 7.6 per cent.) There can therefore be no doubt as to its constitution.

4-Aminoveratrole.

The preparation of 4-aminoveratrole by the reduction of 4-nitroveratrole offered some difficulty owing to the tendency for chlorination to take place simultaneously. Ultimately, the following method was found to give fairly satisfactory results. 4-Nitroveratrole (10 grams) was mixed with tin (16 grams), and, after the addition of a trace of graphite (compare Pinnow, J. pr. Chem., 1901, [ii], 63, 352), hydrochloric acid (50 c.c. of 50 per cent.) was added, and the mixture heated on the water-bath for from two to three hours. The yield of 4-aminoveratrole, isolated in the usual manner, was about 50 per cent. of the theoretical.

Nitration of 4-Acetylaminoveratrole.

To nitric acid (D 14; 6 grams), well cooled in a mixture of salt and ice, finely powdered 4-acetylaminoveratrole [VII] (2 grams) was gradually added. The nitration proceeded with considerable evolution of gas, and in a short time the whole mass became pasty. After fifteen minutes, the mixture was poured on ice, when a yellow solid separated. This was collected, and found to melt at 1950 (14 grams). It was crystallised from alcohol, when it was obtained in golden-yellow needles melting at 196°, and was found to be identical in every respect with the 5-nitro-4-acetylamino

veratrole obtained by the nitration of 6-acetylamino-3: 4

dimethoxybenzoic acid (see above):

0.0727 gave 0·1337 CO2 and 0·0352 H2O. C=50·1; H=5·3. C10H12O5N2 requires C=500; H=50 per cent.

By ALFRED SENIER and PATRICK HUGH GALLAGHER.

THIS Communication is a report of further study of the condensation products of aromatic aldehydes with amines, the anils, or Schiff's bases, with a view to the discovery and special examination of such as might exhibit phototropic or thermotropic change.

Previous communications have shown that whilst compounds of this class are generally thermotropic, they are not phototropic unless they contain an hydroxyl group in an ortho-position with respect to the aldehyde group of the benzylidene nucleus. Moreover, the property appears to be inhibited by the entry into the nucleus of such substituents as bromine, methyl, or methoxyl.

With one possible exception (Foresti, Atti R. Accad. Lincei, 1914, [v], 23, ii, 270), phototropy has not been observed except in the case of solids, and it has been suggested (Senier and Shepheard, T., 1909, 95, 1944) that it is not due to intramolecular change, but to reversible extra-molecular rearrangement of the molecules into molecular aggregates. In order to determine, if possible, whether this explanation or some other is the true one, we are endeavouring to discover further instances of phototropic compounds for study.

This

We wished to examine the 2-hydroxycinnamylideneamines, but practical difficulties at the present time have prevented us. paper contains, however, an account of the preparation and investigation of the simpler cinnamylideneamines, and also of 2:4-dihydroxybenzylideneamines, which latter contain, in addition to an o-hydroxyl group, another hydroxyl group in the p-position.

None of the compounds is phototropic between "the lower temperature," that of solid carbon dioxide, and "the higher temperature," just below their melting points. Prolonged exposure to actinic light, however, induces permanent polymorphic change in many instances. Thermotropy was detected in nearly all cases. Differences of colour in solution depending on the solvent employed were generally observed. The solutions in acetic acid or chloroform were usually deeper in colour than those in light petroleum, benzene, or acetone (compare Senier and Shepheard, T., 1909, 95, 1943). Trituration appears to yield a polymorphic variety in the case of cinnamylidene-m-bromoaniline, but was not otherwise observed. No tritoluminescence was detected.

The 2:4-dihydroxybenzylidene derivatives exhibit marked dichroism in solution. They are green in very thin layers or in dilute, and yellow in thicker layers or when the solutions are concentrated. The green colour of thin layers appears to partake of the character of fluorescence, for it persists when viewed with light from a blue or violet light-filter.

Most of the compounds are readily formed by mixing alcoholic solutions of the aldehyde and base. The ortho-substituted anilines, however, combine with the aldehydes only on prolonged heating at 100°. Attempts to prepare mono-derivatives of phenylene- and naphthylene-diamines resulted in the formation of di-derivatives.

The source of actinic light employed was direct sunlight or a mercury lamp. The compounds dissolve generally in the usual organic solvents; any important exception is noted.

5

Cinnamylideneaniline, CH, CH:CH·CH:N-CH, (Döbner and Miller, Ber., 1883, 16, 1665), consists of yellow plates which melt at 109° (corr.). It is changed into a deeper coloured polymorphic form by the prolonged action of actinic light, and is thermotropic at both "the higher" and "the lower temperatures."

Cinnamylidene chloroanilines, CH5•CH:CH•CH:N•C ̧HCl. Cinnamylidene-o-chloroaniline at first separates mixed with tarry matter, which may be removed by careful washing with alcohol, light petroleum, or ether. After several crystallisations, it becomes nearly colourless, the crystals showing a pale greenishyellow tinge. It melts at 63.5° (corr.):

0.1324 gave 7 c.c. N2 at 17° and 767 mm. N=5.96.

C15H12NCI requires N=5.80 per cent.

This compound shows no change of colour by the action of actinic light or by changes of temperature.

Cinnamylidene-p-chloroaniline (James and Judd, T., 1914, 105, 1430) crystallises in pale yellow or, as in our experiment, in nearly colourless plates which melt at 107° (corr.). It is not phototropic, but exhibits thermotropy at "the higher," and in a less degree at "the lower temperatures."

Cinnamylidenebromoanilines, CH2•CH:CH·CH:N•C ̧H1Br. Cinnamylidene-o-bromoaniline separates from alcoholic solution in pale greenish-yellow clusters which melt at 74° (corr.): 0.1668 gave 7.1 c.c. N2 at 19° and 762 mm. N=4.98. C15H18NBr requires N=4.88 per cent.

13

Slight thermotropy was detected both above and below the ordinary temperature.

Cinnamylidene-m-bromoaniline (James and Judd, T., 1914, 105, 1434) consists of pale yellow plates which melt at 122° (corr.). (The above authors found 115-116°.) Prolonged action of actinic. light produces a slight permanent deepening of colour, and slight evidence of thermotropy was observed.

Cinnamylidene-p-bromoaniline crystallises from alcohol, chloroform, or benzene in pale greenish-yellow plates which melt at 120° (corr.). A permanent deepening in colour occurs when this com

pound is submitted to the prolonged action of actinic light, and thermotropy was observed at "the lower temperature."

0.1402 gave 5'9 c.c. N2 at 16° and 768 mm.

N=4.885.

C15H1NBr requires N=4.88 per cent.

Cinnamylidenetoluidines, CH, CH:CH·CH:N CH1Me. Cinnamylidene-o-toluidine (James and Judd, T., 1914, 105, 1433), which melts at 73°, is not affected by actinic light or by temperature changes under its melting point.

Cinnamylidene-m-toluidine is neither phototropic nor thermotropic (Senier and Shepheard, T., 1909, 95, 1955).

Cinnamylidene-p-toluidine (Tinkler, T., 1913, 103, 894) consists of pale greenish-yellow plates which melt at 83° (corr.). Slight deepening of colour occurred by the prolonged action of actinic light. No evidence of thermotropy was observed.

Cinnamylidenenitrotoluidines, CH ̧•CH:CH•CH:N•C ̧H ̧Me•NO2. Cinnamylidene-4-nitro-o-toluidine forms pale greenish-yellow clusters which melt at 126° (corr.):

0.1140 gave 104 c.c. N2 at 19° and 757 mm. N=10.54. C16H1502N2 requires N=10.50 per cent.

This compound forms deeper coloured solutions in alcohol or acetic acid than in the other ordinary solvents. It is not phototropic, but is thermotropic at "the higher temperature." Cinnamylidene-2-nitro-p-toluidine crystallises from alcohol in pale yellow leaflets which melt at 108° (corr.):

N=10.58.

0.2388 gave 21·2 c.c. N2 at 15° and 767 mm. C16H15O2N2 requires N=10.50 per cent.

This compound is not affected by actinic light, but exhibits thermotropy at both "the higher" and "the lower temperatures. Cinnamylidene-m-nitroaniline (James and Judd, 1914, 105, 1434) is not thermotropic, nor is it affected by actinic light.

Cinnamylidene-p-anisidine,

CH ̧•CH:CH•CH:N⚫CH OMe, is obtained from solutions in alcohol in large yellow plates which melt at 119° (corr.):

0.1106 gave 5.6 c.c. N2 at 16° and 759 mm. N=6.00. C16H15ON requires N=5.93 per cent.

This base dissolves sparingly in cold alcohol. Acetic acid changes the yellow crystals into a scarlet, probably dimorphic variety, which we propose to examine further. It is not affected

by actinic light, but is slightly thermotropic at "the lower temperature."

Cinnamylidene-p-phenetidine,

C&H CH:CH⚫CH:N·C&H1·OEt,

5

consists of pale green, lustrous plates which melt at 108° (corr.). Like the preceding base, acetic acid changes it into a red dimorphic variety, which crystallises in prisms. It is slightly thermotropic, but is not phototropic :

0.1328 gave 6.2 c.c. N2 at 15° and 767 mm. N=5'58. C17H17ON requires N=5.58 per cent.

Cinnamylidene-p-xylidine, CH ̧·CH:CH·CH:N.CH,Me, separates in pale yellow needles which melt at 111.5° (corr.):

0.0856 gave 43 c.c. N2 at 15° and 764 mm.

N=6.08.

This compound is not affected by actinic light, but exhibits slight thermotropy at both "the higher" and "the lower temperatures."

5

Cinnamylidene--cumidine, CH, CH:CH·CH:CH2Meg (Schiff, Annalen, 1887, 239, 384), which melts at 105°, is not affected by actinic light, but is thermotropic at both "the higher" and "the lower temperatures."

Cinnamylidenenitro-y-cumidine,

5

2

C&H CH:CH·CH:N C&HMeg NO2 -This base separates at first in orange-red needles. After several recrystallisations, yellow crystals are obtained, which revert to orange-red on keeping. After further recrystallisations, however, the product retains its yellow colour. It melts at 117° (corr.). Actinic light has no effect on this base, nor is it thermotropic :

0.2424 gave 20 c.c. N2 at 17° and 759 mm. N=9.63. C18H18O2N2 requires N=953 per cent.

C&H CH.CH.CH:N•C10H7

Cinnamylidene-B-naphthylamine, (Schiff, Annalen, 1887, 239, 384), is stated to melt at 95-96o. Our specimen melts at 124° (corr.). (Found, N=5'41. C19H15N requires N=5:46 per cent.)

This base is neither phototropic nor thermotropic, but by the prolonged action of actinic light it changes into a deeper coloured polymorphic form.

Cinnamylidenecamphylamine was prepared, but as it proved to be a liquid and the quantity was small, we did not proceed with it further.

Dicinnamylidene-p-phenylenediamine,

(CH, CH:CH·CH:N)2C6H4,