CHATTAWAY AND MASON : HALOGEN DERIVATIVES, ETC. 339XXXV IT I. - Hul og e n Deriva t iues of 2Lfal on m i l i d e , E t h y 1Mcdonanilate, and iLIulonccnilic Acid.By FREDERICX DANIEL CHATTAWAY and FREDERICK ALFRED MASON.COMPOUNDS of this nature are a t present almost unknown, althougha knowledge of their properties is necessary before the action ofhalogens on the parent substances can be followed and beforeone of the least studied cases of intramolecular rearrangement canbe further investigated.The scanty literature dealing with the subject leaves theimpression that compounds of this class are difficult to prepare bya direct method, whereas the exact reverse is the case.The halogen derivatives of malonanilide and of ethylVOL XCVII. A 340 CHATTAWAF AND MASON : HALOGEN DERlVATIVES OFmalonanilate are produced together when malonic ester in someexcess is heated for a short time with the corresponding aniline, andcan easily be separated, owing to the sparing solubility of theanilides in all ordinary solvents.The best results are obtainedwhen about one gram-molecule of the aniline and one and a-halfgram-molecules of malonic ester are employed; if less ester is used,some aniline, which is troublesome to remove by crystallisation, isleft, whilst if more ester is taken, the products remain partlydissolved in the excess which has to be distilled off, a brownish-coloured product, which needs much purification, being obtained.About 10 to 15 grams of aniline is a convenient amount to use inone operation.The aniline and ester are heated together in a flask attachedto a long tube, which serves as a condenser, and the rate of boilingof the mixture is r.egulated so that the alcohol formed mainlyescapes while the malonic ester is returned to the flask.The yields are generally good, no appreciable decompositionoccurring, the loss arising only from the necessary separation andpurification.The halogen-substituted malonanilic acids are also very easilyobtained by hydrolysing the substituted malonanilic esters : thecrude products from which the substituted malonanilides have beenseparated suffice for this purpose.The esters can be hydrolysed by heating for a short time withaqueous sodium or potassium hydroxide, or even by heating for alonger time with water alone, but it is preferable to suspend themin a dilute solution of sodium carbonate and to pass steam throughthe liquid until the ester disappears. This method has theadvantage that if any aniline remains admixed with the crudeester or is formed during hydrolysis, it passes over with the steam.The acid is separated from the sodium salt in a crystalline state,after concentrating the solution if necessary, by adding a slightexcess of hydrochloric acid.When heated, the malonanilic acids decompose quantitativelyinto carbon dioxide and the corresponding substituted acetanilide,thus, for example :C6H4BroNH*CO*CH2*C0,H = CO, + C,H4Br*NH*CO*CH3.EXP E RIM EN TA L.pp-DichZoromaZonanilide, C6H4C1*NH*CO*CH,*C~*NH0C6H4~~.This compound, together with ethyl p-chloromalonanilate, isproduced when p-chloroaniline is heated with ethyl malonate.Amixture of 12 grams of p-chloroaniline and 25 grams of ethyMALONANILIDE, ETHYL MALONANILATE, AND MALONANILIC ACID 341malonate was gently boiled for thirty minutes, the alcohol formedbeing allowed to escape. The semi-solid mass left on cooling wasshaken with four times its bulk of alcohol, and the dichloromalon-anilide which remained undissolved was collected and recrystallisedalternately from alcohol and acetic acid. It is fairly soluble inboiling alcohol or acetic acid, and separates from either in small,slender, colourless needles, which, when dry, form a felted mass.The yield of pure product obtained thus is about 20 per cent.ofthe theoretical yield from the amount of aniline used.pp-Dichloromalonanilide melts and decomposes a t 261O :0,2474 gave 0.2206 AgC1. Cl= 22.06.C,,Hl20,N2C1, requires C1= 21.95 per cent.Ethyl p-Chlorom,alonanilate, CGH,C1*NH*CO*CH2*C0,*C2H6.This compound was obtained as a white, crystalline powder byslowly adding water to the filtrate from which dichloromalonanilidehad been separated. It was purified by repeatedly crystallising i tfrom hot alcohol, in which it is very easily soluble, and from whichit separates in short, colourless prisms, melting at 97O. It is veryreadily soluble in all common organic solvents, but only verysparingly so in water:0.2146 gave 0.1285 AgC1. C1= 14.81.C,,H,,O,NCl requires C1= 14.68 per cent.p-Chloromalonanilic A cid, C,H,C1*NH-CO*CH2*C02H.This compound was prepared by suspending ethyl pchlcro-malonanilate in twenty times its weight of water containing rathermore than the equivalent amount of sodium carbonate and passingsteam through the liquid until the ester had disappeared.Onadding hydrochloric acid in slight excess to the cooled product,the acid separated in thin, colourless plates. It was purifiedby recrystallisation either from hot water, in which it is mod-erately soluble, or from hot alcohol, in which it is readily so. Itseparates from either solvent in glistening, colourless, flattenedprisms or plates. On heating, it melts and decomposes, and evolvescarbon dioxide at about 16F',* leaving a residue of pure p-chloro-acetanilide, which, after solidification, re-melts a t 175O :* The melting points of this and the other substituted malonanilic acids describedin the paper represent the temperatures a t which the substances melt and rapidlydecompose with gas evolution when quickly heated.The ternpcratures a t whichthis melting takes place vary considerably with the rate of heating. Decompositionoccurs to some extent before these temperatures are reached, and if the acids areslowly heated, they appear to melt at lower temperatures.A A 342 CHATTAWBY AND MASON: HALOGEN DERIVATIVES OF0.2123 gave 0.1439 AgCl. C1= 16.77.C,H,O,NCl requires C1= 16.61 per cent.2 : 4 : 2/ : 4f-TetrachloromalolzaniZ~~e,C,H,Cl,*NH*CO*CH,*CO*NH*C,H3C12.This compound was obtained, together with ethyl 2 : 4-dicliloro-malonanilate, by boiling for about forty-five minutes a mixture of16 grams of 2 : 4-dichloroaniline and 24 grams of ethyl malonate.The tetrachloromalonanilide was separated as described under thecorresponding dichloro-compound, and purified by recrystallisationfrom boiling acetic acid.It is very sparingly soluble in boilingalcohol, and moderately so in boiling acetic acid. It crystallises incolourless, long, flattened needles or prisms, melting at 214O :0.2558 gave 0.3748 AgC1. C1= 36.25.C,,H,,O,N,Cl, requires C1= 36.19 per cent,Ethyl 2 : 4-Bic7~ZoromaZonaniZate, C,H3Cl,-NH*CO*CH2*C02*C2H,.This compound separated on cautiously adding water to thealcoholic filtrate from which the tetrachloromalonanilide had beenseparated.It was several times recrystallised alternately fromboiling acetic acid and alcohol, in both of which it is readilysoluble. It crystallises in colourless, flattened prisms, meltinga t 8 1 O :0.2527 gave 0.2620 AgC1. C1= 25.65.C,,Hl1O3NC1, requires C1= 25.69 per cent.2 : 4-Dic7~ZoromaZonaniZic A cid, C,H,Cl,*NH-CO*CH,*CO,H.This compound was prepared exactly as described under p-chloro-malonanilic acid. It is sparingly soluble in hot water, readilyso in boiling alcohol, and crystallises from the latter in colour-less, slender, flattened prisms. It melts and evolves carbon dioxideat about 1 6 4 O , and leaves a residue of pure 2 : 4-dichloroacetanilide :0.2896 gave 0.3337 AgCl.C,H,O,NCl, requires C1= 28.60 per cent.C1= 28.50.2 : 4 : 6 : 21 : 4/ : 6~'-Hexac?doromaZonanibide,C6H,C13*NH*CO*CH,*CO*NH*C6H2C13.2 : 4 : 6 : 2' : 4' : 6~-Hexachloromalonanilide, together with ethyl2 : 4 : 6-trichloromalonanilate, was prepared by gently boiling foran hour a mixture of 20 grams of 2 : 4: 6-trichloroaniline and 40grams of ethyl malonate, allowing the alcohol formed to escape.About 20 grams of unchanged malonic ester were then distilleMALONANILIDE, ETHYL MALONANILATE, AND MALONANLLIC ACID 343off.The residue was boiled with about 200 C.C. of alcohol, and thehexachloromalonanilide, which is practically insoluble in alcohol,was filtered off from the hot liquid. After washing repeatedlywith boiling alcohol, the white, crystalline residue was several timescrystallised from boiling acetic acid, in which i t is sparingly soluble,and from which it crystallises in colourless, very slender, hair-likeneedles.It turns brown, melts, and evolves gas at about 306O:0.1911 gave 0.3545 AgCl. C1=45.89.C1,H,O,~,C1, requires C1= 46.17 per cent.Ethyl 2 : 4 : 6-TrichloromtzlonaniEate,C,H,CI,*NH* CO*CI3,*CO2*C2H5.This was obtained by adding water to the alcoholic filtrate fromthe hexachloromalonanilide and repeatedly crystallising the esterthus separated from boiling alcohol. It is easily soluble in hotalcohol, and crystallises in colourless, slender prisms, melting at141O :0.3361 gave 0.4643 AgCI. C1= 34.17.C,,H,,O,NCl, requires C1= 34.26 per cent.2 : 4 : 6-T~ichZoroniaZonan~Z~c A cia?, C,H,C~,~~~*C'O~CH,~CO,H.This was prepared exactly as were the previously described acids.It Wacs repeatedly crystallised from boiling alcohol, in which it ismoderately easily soluble. It crystallises from alcohol in colourless,slender prisms, and from boiling water, in which it is sparinglysoluble, in small, fine, colourless needles. When heated, it meltsand evolves carbon dioxide at about 172O, forming 2 : 4 : 6-trichloro-acetanilide :0.1643 gave 0.2495 AgCl.CIz37.57.C,H,03NC13 requires C1= 37-66 per cent.pp -Dib romomdonan&de, C,H,Br- NHo CO*C~,*C~*NH*C,~,Br.Each bromine compound was prepared and isolated in a mannerresembling that described under bhe corresponding chlorine com-pound, so that it is only necessary to record their distinctivepeculiarities.pp-Dib romonzaZonan&de is sparingly soluble in boiling akohol,and moderately so in hot acetic acid.It crystallises from eithersolvent in colourless, slender needles, melting at 268O. I f kept a tthis temperature, some decomposition takes place, the fused sub-stance turning brown and giving off bubbles of gas. The otherhalogen-substituted malonanilides behave similarly :0.2865 gave 0-2598 AgBr. Br = 38-59.C,,R,,O2N,Br2 requires Br = 38.80 per cent344 CHATTAWAY AND MASON: HALOGEN DERIVATIVES OFEthyl p-Br omomaZonadut e, C6H4Br~~H~C'O~CH20C020C,H,.Ethyl p-bromomalonanilate crystallises from alcohol, in which itis easily soluble, in colourless, short, rhombic prisms, melting at 99O :0.2715 gave 0.1788 AgBr.Cl1Hl2O3NBr requires Br = 27.94 per cent.Br = 28.03.p-Bromomalonanilic A cid, C,H,Br*NH*CO*CH,-CO,H.This compound is sparingly soluble in boiling water, but readilyso in hot alcohol.It crystallises from water or alcohol in colourless,flattened, slender prisms. It melts at 169O, carbon dioxide isevolved, and p-bromoacetanilide is formed :0,1750 gave 0.1271 AgBr. Br = 30.91.CgHs03NBr requires Br = 30.98 per cent.2 : 4 : 21 : 4f-TetrabrommaZonaniZide,C,H3Br20NH*CO*CH2*CO*~H*c6€~3Br2.This compound crystallises from boiling acetic acid, in which itis moderately soluble, in colourless, long, flattened ueedles or prisms,melting at 233O :0.2092 gave 0.2769 AgBr. Br = 56-33.C1,Hl,02N2Bra requires Br =56-11 per cent.EthgZ 2 : 4-BibromomaZonanilate,C6H3Br,oNH*C 0 CH2*C0,* C2H5.This compound crystallises from alcohol, in which it is easily0.2431 gave 0.2496 AgBr.Br=43*69.soluble, in colourless, slender, flattened prisms, melting a t 86O :CllH1103NBr2 requires Br = 43-80 per cent.2 : 4-DibromdonaniZic A cid, C6H3Br2*NH*CO*CH2*C02H.2 : 4-Dibromomalonanilic acid is sparingly soluble in water, buteasily so in alcohol. It crystallises from alcohol in colourless,flattened prisms. When heated, it melts, and evolves carbon dioxideat 174O, 2 : 4-dibromoacetanilide being formed :0.2880 gave 0.3195 AgBr. Br =47*21.C,H,03NBr2 requires Br =47*44 per cent.2: 4: 6 : 21: 41: 6~-HexabromomaZonartilide;C,H2Br,*NH~CO~CH2-CO~NH*C,H2Br3.This anilide is so sparingly soluble in all ordinary solvents thatit can only be recrystallised in very small amount from boilingacetic acid.A few tenths of a gram only are dissolved by a litrMALONANILIDE, ETHYL MALONANILATE, AND MALONANILIC ACID 345of boiling acetic acid. It separates from this solvent in colourless,very small, hair-like needles. It can be recrystallised from boilingnitrobenzene, but the product obtained is not quite pure, and veryconsiderable loss from decomposition occurs. It melts and evolvesgas a t 331O:0.1314 gave 0.2041 AgBr.C,,H,O,N,Br, requires Br = 65.90 per cent.Freund (Ber., 1884, 17, 782) obtained a compound to which heassigned this constitution by dissolving malonanilide in glacialacetic acid, and adding bromine in slight excess to the warmedsolution drop by drop. The liquid on cooling deposited a thickcrop of needles, which, after several recrystallisations from aceticacid, melted at 145--146_O.This substance, on heating in a sealedtube with fuming hydrochloric acid at 200°, yielded a, compoundwhich he regarded as symmetrical tribromoaniline, and from thisobservation he deduced its constitution.Freund's compound, however, differs so entirely in its properticsfrom the compound described above, which itself possesses all theproperties that would be expected from a consideration of thoseof the other members of the class described in this paper, thatit cannot have the constitution assigned by him to it.Br = 66.10.Ethyl 2 : 4 : 6-TribromodonaniZate,C6H2Br3-NH*CO*CH2*C0,*C,H,.Ethyl 2 : 4 : 6-tribromomalonanilate is readily soluble in hotalcohol, and crystallises from it in colourless, slender prisms, meltingat 177O:0.1458 gave 0.1854 AgBr. Br=54*11.C,,H,,03NBr, requires Br = 54.02 per cent.2 : 4 : 6-TribromomuZonaniZic A cid, C,H,Br3*NH*CO*CH,*C0,H.2 : 4 : 6-Tribromomalonanilic acid crystallises from alcohol, inwhich it is moderately soluble, in small, colourless needles. If theacid is rapidly heahd, it melts and evolves carbon dioxide a tabout. 201°, 2 : 4 : 6-tribromoacetanilide being produced. If slowlyheated, however, it decomposes below this temperature withoutmelting, carbon dioxide as before is given off, whilst 2 : 4 : 6-tri-bromoacetanilide, which, if the temperature be raised, melts sharplyat 232O, is left in the tube:0.2000 gave 0.2699 AgBr. Br = 57-43.C,H,O,NBr, requires Br = 57.66 per cent.UNIVERSITY CHEMICAL LABORArORY,OXFORD