XLIV .-Quantitative Reduction by H ydriodic Acid of Halogenated Malonyl Derivatives. Part I. The Amides and s.-Di-alkyl-and-aryl-substituted Amides of Mono-and Di-bromomalonic Acid. By JOHN VALENTINE BACKES, RALPH WINTON WEST, IT was observed by one of us (Whiteley, P., 1908, 24, 288) that the bromine in the bromomethylene complex of certain mono-and di-bromomalonyl derivatives, *CO*CHBr*CO* and *CO*CBr,*CO*, is reactive towards hydriodic acid in the same sense as the halogen in the nitrogen-halogen complex ; such compounds liberate iodine from hydriodic acid at the ordinary temperature according to the following equations : (11,) *CO*CBr,CO* + 4HI = *CO*CH,-CO*-t 2HBr + 21,.

Reduction of Aromatic Nitro-compounds. By RALPH WINTON WEST.ON the laboratory scale, considerable difficulty is often experienced in the reduction of aromatic nitro-compounds to the corresponding amines. The difficulty of regulating the energy of the reduction often leads to decomposition of the amine, with the formation of undesirable products, Thus, the main product of the reduction by stannous chloride of o-bromonitrobenzene is aniline, whilst a considerable quantity of the free amino-acid is produced in the reduction of ethyl p-nitrobenzoate. I n other cases, the method of working up the product of the reduction is inconvenient and wasteful ; e.g., m-dinitrobenzene to m-phenylenediamine. The method here described has been found to give good yields of very pure products. The nitro-compound (1 g.-mol.) is heated to boiling on the waterbath with methylated spirit (500 c.c.) and concentrated hydrochloric acid (10 c.c.). Iron filings (170 g. for each nitro-group present in the compound) are introduced in four portions, 5 minutes being allowed between each addition. The mixture should be kept a t vigorous ebullition in order to prevent the iron from caking, and the heating continued for 2 hours after the final addition of iron. The subsequent treatment of the solution depends on the nature of the amino-compound.(a) It may be made alkaline with caustic soda (10 g.) and steamdistilled. I n this way, the first distillate of alcohol is collected separately from the turbid distillate of the substance.(b) After addition of alcoholic caustic soda equivalent to the hydrochloric acid employed, the hot liquid is filtered and the residue washed once with spirit. The bulk of the alcohol is removed by distillation, and the hydrochloride of the base precipitated by the addition of concentrated hydrochloric acid.

ACID, ETC. 1277 CLVI1.-TheAction between Bromine and Malonic *4cid in Aqueous Solution.By RALPH WINTON WEST. DURING his investigation of keto-enol tautomerism, K. H. Meyer (Bey., 1912, 45, 2864), on somewhat scanty evidence, arrived at the conclusion t,hat the reaction between bromine and malonic acid was independent of the concent'ration of the former, and was of the unimolecular type indicated by the scheme .CH,-CO* -%$ 43H:C.OE rapi; *CHBr.CBr*OK rapid, -CHBr-CU.Thus t,he measurable stage consisted in the slow change from the keto to the enol form of the acid, which was brominated almost instantaneously.Having regard to the genera1 behaviour of malonyl compounds

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