sodium hydroxide on prolonged boiling; the hydrolysis may also be effected by the action of hot alcoholic hydrochloric acid. The base crystallises from dilute alcohol in colourless needles, and from benzene in feathery aggregates of acicular prisms; it darkens slightly on exposure and melts at 136-137°.

0.1167 gave 0.1882 AgCl. Cl = 40·75.

0.1092

15.6 c.c. moist nitrogen at 22 and 759 mm. N=16·16. CH.N2Cl2 requires Cl=41.13; N=15.82 per cent.

2

Diacetyl-1: 5-dichloro-2 : 4-phenylenediamine may also be prepared by the direct chlorination of diacetyl-m-phenylenediamine, the latter substance, when dissolved in 3-4 parts by weight of glacial acetic acid and treated with excess of chlorine (over 2 mols.), yields the dichloroderivative exclusively; there is apparently no tendency for the formation of a trichloro-compound.

Three grams of the dichloro-base and 3.2 grams of cuprous chloride are dissolved in 35 c.c. of concentrated hydrochloric acid and 10 c.c. of water and treated at 80-90° with 1.6 grams of sodium nitrite dissolved in 16 c.c. of water; the solution is then heated to boiling for a short time, and subsequently distilled in steam. The solid, yellow product obtained in the 'distillate has an odour of chloranil, and on crystallisation from alcohol yields 1:2:4: 5-tetrachlorobenzene; this compound, when purified by sublimation, is obtained in long, colourless needles melting at 137–138°.

Action of Hypochlorous Acid on Diacetyl-m-phenylenediamine.

Ten grams of diacetyl-m-phenylenediamine are dissolved in 400 c.c. of boiling water, and the solution rapidly cooled to obtain small crystals; 30-40 grams of potassium hydrogen carbonate are then added, and the mixture treated with 150 c.c. of a sodium hypochlorite solution containing 30 grams of chlorine per litre. After a short time the precipitate is collected, washed until free from hypochlorite, and dried on porous plates. The product, m-phenylenediacetyldichloramine, CH1(NCI.CO.CH)2, is readily soluble in benzene or chloroform, and crystallises from its solution, on the addition of light petroleum, in hard, colourless prisms or octahedra. The compound liberates iodine from a solution of potassium iodide, and a quantitative examination showed that it contains 2 atoms of labile chlorine. Weighed portions were dissolved in chloroform, treated with excess of potassium iodide solution, and titrated with standard thiosulphate.

0.1718 liberated 0·3358 I. Cl = 27.42.

m-Phenylenediacetyldichloramine melts at 150-151° to a colourless liquid, which almost immediately decomposes with explosive violence; when boiled with glacial acetic acid, it is converted into diacetyl-1:5dichloro-2 : 4-phenylenediamine, the latter compound crystallising from the solvent in white, felted needles. The diamine produced through the agency of hypochlorous acid was shown to be identical with that obtained by chlorination by the direct comparison of the two specimens and their benzoyl derivatives; moreover, it yields 1:2:4:5-tetrachlorobenzene when submitted to the Sandmeyer reaction. Dibenzoyl1:5-dichloro-2: 4-phenylenediamine, prepared as a means of identifying the dichloro-base, crystallises from benzene or chloroform in white, felted needles which darken on exposure to light, and melt at 187°. 0.1128 gave 0.083 AgCl. Cl= 18.20.

C20H14NaCl, requires Cl= 18.44 per cent.

When finely divided dibenzoyl-m-phenylenediamine is suspended in a saturated solution of potassium hydrogen carbonate and treated with excess of sodium hypochlorite, it yields a dichloramine corresponding with m-phenylenediacetyldichloramine; it is, however, less stable than this compound, and readily passes into dibenzoyl-1 : 5-dichloro2: 4-phenylenediamine (m. p. 187°) on boiling with chloroform or benzene.

Bromination of Diacetyl-1-bromo-2 : 4-phenylenediamine.

Ten grams of diacetyl-1-bromo-2: 4-phenylenediamine, dissolved in two parts by weight of glacial acetic acid, are treated with 1 mol. of bromine diluted with two parts by weight of the same solvent; the product, added to water containing a little sulphurous acid, yields a brown precipitate which is hydrolysed with 30 c.c. of concentrated hydrochloric acid. The base, obtained on neutralising the acid solution, crystallises from alcohol in needles and melts at 135°; it appears to be identical with the dibromo-2: 4-phenylenediamine prepared by Jackson and Calvert by the direct bromination of diacetyl-m-phenylenediamine (Amer. Chem. J., 1896, 18, 482). This diamine, when submitted to the Sandmeyer reaction in the presence of cuprous bromide, yields a tetrabromobenzene, which, after sublimation and recrystallisation from alcohol, melts at 174° and does not depress the melting point of the 1:2:4: 5-tetrabromobenzene prepared by the direct bromination of p-dibromobenzene; accordingly, the base is 1: 5-dibromo-2: 4-phenylenediamine.

Action of Hypobromous Acid on Diacetyl-m-phenylenediamine.

The finely divided diacetyl-m-phenylenediamine is suspended in a cold, saturated solution of potassium hydrogen carbonate and treated with excess of potassium hypobromite solution; the insoluble product has a yellow colour when first collected, but becomes almost colourless on drying. This substance still gives the substituted bromamine reaction with potassium iodide, but seems to consist principally of the transformed diacetyldibromo-m-phenylenediamine. A portion crystallised from chloroform melts at 259-260°, this being the melting point of diacetyl-1:5-dibromo-2 : 4-phenylenediamine; the melting point of the diamine, obtained on hydrolysis, is 133°, whilst that of pure 1:5-dibromo-2: 4-phenylenediamine is 135°.

5-Chloro-2: 4-tolylenediamine.

A solution of diacetyl-2: 4-tolylenediamine (m. p. 221°) in 3 parts by weight of glacial acetic acid, when treated with 1 mol. of chlorine and subsequently diluted with water, yields a brownish-white, crystalline precipitate of diacetyl-5-chloro-2: 4-tolylenediamine. The corresponding diamine, obtained by hydrolysing the preceding compound with alcoholic hydrochloric acid and neutralising the hydrochloride solution with ammonia, crystallises from water in colourless, nacreous leaflets which turn pink on exposure to the air. When crystallised from benzene, the base separates either in long, colourless, elastic lamellæ or in thin, rectangular plates; it melts at 120-121°.

0.1328 gave 0-1226 AgCl. Cl=22.82.

0.2185 34.2 c.c. moist nitrogen at 18° and 758 mm. N=18.03. C,H,N,Cl requires Cl=22.68; N=17.89 per cent.

The diacetyl derivative crystallises in small, acicular prisms melting at 239-240°.

Three grams of sodium nitrite, dissolved in 30 c.c. of water, are slowly added to a hot solution of 4 grams of 5-chloro-2: 4-tolylenediamine and 4 grams of cuprous chloride in 30 c.c. of concentrated hydrochloric acid and 10 c.c. of water; the mixture is maintained at 80-90° until the evolution of nitrogen has ceased, and subsequently distilled in steam. The volatile product, consisting of 15 grams of crude trichlorotoluene, is purified by sublimation and recrystallisation from alcohol; it crystallises in colourless, flattened needles and melts at 81.5°, the melting point of Limpricht's 2:4: 5-trichlorotoluene being 82°.

1:5-Dichloro-2: 4-phenylenediamine, its bromine analogue, and

5-chloro-2: 4-tolylenediamine all contain substituent radicles in both the para-ortho-positions relatively to the amino-groups, and they react less readily with diazonium salts than the mono-substituted m-phenylenediamines; they do, however, combine with certain diazocompounds such as diazobenzenesulphonic acid, and hence the azoresidue must enter the ortho-position contiguous to the two aminoradicles. A study of these azo-compounds will form the subject of a subsequent communication.

ROYAL COLLEGE OF SCIENCE, LONDON,
SOUTH KENSINGTON, S.W.

CXIV.—Action of Aromatic Aldehydes on Derivatives of B-Naphthylamine.

By GILBERT THOMAS MORGAN, D.Sc.

BENZYLIDENE-B-NAPHTHYLAMINE is the first product of the action of benzaldehyde on B-naphthylamine, and on further condensation with excess of the base it yields a colourless substance (dihydrophenylnaphthacridine ?), from which phenylnaphthacridine is obtained by oxidation (Claisen, Annalen, 1889, 239, 272).

The formation of condensation products containing the aldehydic carbon atom directly attached to the aromatic nucleus of the ẞ-naphthylamine residue takes place, however, far less readily with benzaldehyde than with formaldehyde, for in the case of the latter the methylene residue always takes up its position in the ring unless the amine employed already contains a substituent radicle in the a-position contiguous to the B-amino-group (Morgan, Trans., 1898, 73, 536; this vol., 814).

5

10

42

When ethyl-ẞ-naphthylamine is treated with benzaldehyde dissolved in cold glacial acetic acid, a substance is slowly produced by the elimination of one mol. of water from three mols. of the aldehyde and two of the base. 3CH, CHO+2C10H2•NH·C2H2 = C45H12O2N2+ H2O. This compound, a well defined crystalline substance melting at 148°, is readily hydrolysed into its generators by mineral acids, and therefore does not contain an aldehydic carbon atom attached to the naphthalene nuclei. When treated with phenylhydrazine in warm glacial acetic acid, it is decomposed with the formation of benzylidene phenylhydrazone and the regeneration of ethyl-ẞ-naphthylamine.

2C10H, NH C2H2+зCH ̧·CH:N•NH•C2H ̧ + 2H2O.

2 5

Although the study of the anhydro-bases derived from the aromatic aldehydes and primary aromatic amines has engaged the attention of many investigators, yet very few instances of the combination of benzaldehyde and its homologues with monoalkyl aromatic amines have hitherto been recorded. By the action of this aldehyde on ethylaniline, Schiff obtained the base benzylidenediethyldiphenylamine as an uncrystallisable resin, the condensation taking place in the following manner:

2CH ̧•NHEt + C2H ̧•CHO = С2H ̧·CH(NEt C ̧H5)2 + H2O

(Annalen, Suppl., 1864, 3, 363).

If the initial phase of the reaction with ethyl-ẞ-naphthylamine takes a similar course, the crystalline product may result from the combination of the analogous anhydro-base, CH, CH(NEt C10H)2, with 2 mols. of benzaldehyde, its constitution, on this assumption, being represented by the molecular formula

CH, CH(NEt C10H7)2+2C6H5 CHO. (I).

10

10

On the other hand, the initial product of the reaction may be the additive compound CH, CH(OH) NEt C10H7, and the elimination of water may be regarded as taking place between two mols. of the substance with the formation of the anhydride

C10H, NEt CH(C2H2)•O•CH(C2H2) •NEt•C10H7;

10

the final product would then result from the combination of the latter with 1 mol. of benzaldehyde, the hypothetical formula corresponding with this view being

C10H, NEt CH(C ̧H2)•O•CH(C2H2) NEt C10H2+CH, CHO. (II).

Lastly, the condensation may be supposed to take place in such a manner that the third molecule of benzaldehyde also undergoes rearrangement, the reaction being represented by the following equation :

2CH, CH(OH) NEt C10H7+CH ̧·CHO=

CH,CH<OCH(CH) NEU-CH,

O-CH(CH) NEt C107+H2O. (III.). •O•CH(CH) NEt C10H7

10

On this hypothesis, the substance is represented by a constitutional formula in which the three benzylidene residues are represented as forming an essential part of the structure of the molecule.

If the compound contains benzaldehyde of crystallisation, it might be expected to crystallise from different solvents with varying amounts of this substance; however, it separates unchanged from its solutions in benzene, acetone, ethyl acetate, acetic acid, chloroform, and the alcohols. It is quite stable at its melting point, and does not give off