550 SKINNER AKD RUHEMANN THE ACTION OF XLL-The Action of Phenylhydra.zine on Urea and some of its Derivatives. By SIDNEY SKINNER B.A. and S. RUHEMANK Ph.D. IN this paper we give an account of the action of phenylhydrazine on certain compounds nearly related to urea. I n the first part several substances are described which complete the series of semicarbazides and carbazides both of oxy- and thio-carbamides. The difference between the carbarnides and these substances which contain groups of two atoms of nitrogen united directly is shown by the fact that the latter yield coloured compounds when treated with a mild oxidiaing agent such as copper sulphate or mercuric chloride. The latter part of the paper is devoted to a description of th PHENYLHYDRAZINE ON UREA. 551 reaction of phenylhydrazine with parabanic acid and the comparison of this reaction with that which takes place with alloxan under like conditions.I n the cold phenylhydrazine behaves as ammonia does wikh parabanic acid forming the corresponding normal salt but on boiling with water a hydrazide of oxaluric acid is produced. This reaction is not analogous t o that with ammonia at the temperature of boiling water as that is said to produce the ammonium salt of oxaluric acid. Diphen y 1 curbmid e. When a mixture of 21 mols. of phenylhydrazine and 1 mol. of ethylic carbamate is heated over a small flame until the evolution of ammonia ceases a viscous brown product remains which crystallises after some days; crystallisation may however be at once brought about by adding excess of ether.This compound diphenylcarbazide is in-soluble in ether sparingly soluble in hot water easily in hot alcohol, and is best recrystallised from dilute alcohol. It melts at 151" and gives a deep red coloration with ammonia. The formula CO(NH*NH*CsH5) requires the following values :-Found. Theory. -7 -7 I. 11. C, 156 64.46 p. c. 64-02 Hi4 6.43 - 14 5.80 N4 56 2314 - 22.92 0 . 16 6.60 -- -Its formation takes place in the following way :-+ C2H,*OH. I f the ethereal solution from which the diphenylcarbazide has separated is allowed to stand other crystals come down ; the yield of these however is very small if the experiment is carried out as directed. The meltling point of theae crystals is 172" which is the same as that of phenylsemicarbazide a substance originally obtained by Fischer (Annalen 190,113) from potassium isocyanate and phenyl-hydrazine.Its formation is easily explained thus :-NH Co<NH2 OCnH5 + NH2*NH*C6H6 = CO<NHTNHC6H5 + C2H5*OH. We have also obtained diphenylcarbazide directly from carbamide by the action of an excess of phenylhydrazine 552 SKINNER AND RUHEMANN THE ACTION OF Pellizzari (Gazzetta 16 SOO) and more recently Pinner (Ber. 20, 2358) have described the action of carbamide in slight excess on pheny lhydrazine or its hydrochloride and have obtained Fischer's phenylsemicarbazide (melting point 172"). From these results it is evident that both diphenylcarbazide and phenylsemicarbazide may be prepared either from ethylic carbarnate or from carbamide.In fact, by heating diphenylcarbazide with carbamide phenylsemicarbazide results and conversely diphenylcarbazide is formed on heating phenylsemicarbazide with phenylhydrazine. It also follows that one amido-graup of carbamide is equivalent in its reaction with phenyl-hydrazine to the ethyl-group of ethylic carbarnate. Diphen y lsemicar baxide. When equivalent quantities of monophenylcarbamide and phenyl-hydrazine are heated together ammonia is evolved and a product is obtained which becomes solid on cooling. This is washed with ether to remove excess of the hydrazine boiled with water and the insoluble residue crystallised from alcohol. Rosettes of needles melting at 170-171" separate from the hot alcoholic solution. This substance is diphenylsemicarbazide; it is insoluble in ether and water but - -NH-C H dissolves readily in hot alcohol.The formula CO<NH.x6H.5c 6 5 requires :-Found. Theorj. f--J'- -3 r---7 I. 11. - CI3 156 68.72 68.51 H, 13 5.73 6-29 N3 . 42 18.50 - 18.79 0 16 7-04 -- -The reaction takes place in the iollowing way :-This substance is a derivative of oxycarbamide corresponding with the thiocarbamide-derivative CS<NH.N6H.b6H, obtained by Fischer by the action of phenylthiocarbimide on phenylhydrazine. It would doubtless be formed by a similar reaction from phenyl isocyanate and phen yl hy drazine. NH*C H Phenylsei?Lithiocarbazide. We expected by heating a mixture of equivalent quantities of phenylhydrazine and monophenylthiocarbamide to obtain Fischer' PHENYLHYDRAZINE ON UREB.553 diphenylsemithiocarbazide to which we have just referred. On carrying out this experiment however ammonia nitlrogen benzene and aniline were evolved and a white solid remained; this is phenylsemithiocarbaxide. I t is insoluble in ether scarcely soluble in boiling water but comes down in pinkish crystals from its solution in hot alcohol. The These crystals have a melting point of 190". formula CS<N~~NH,c,H5 NH requires :-Found. Theory. r-- 7 I. 11. 111. rA- 7 - - C7 . . . 84 50.30 p. C. 50.56 Hg. 9 5.39 , 5.86 S . . 32 19.16 ,, - -- 19.02 -NB . . . 42 25.14 , - - 25.57 The reaction by which this substance is produced takes place in two stages. During the first ammonia is evolved and diphenylsemi-thiocarbazide is formed thus :-CS<NH.c6H NH2 + NH,*NH*C6H5 = cs<xH'c6H5 NH'NH*C6H5 + NH,.The product of this stage however, cannot be separated for the second begins before the first is complete, and in it phenylhydrazine converts the diphenylsemithiocarbazide into phenylsemithiocarbazide :-That this reaction actually takes place was shown by a direct The formation of aniline probably occurs in the following way with experiment on some diphenylsemithiocarbazide. the direct production of phenylsemithiocarbazide :-+ CgHci'NH2. Pellizzari (Quxxetta 16 200) has described a substance which he calls a phenylsemithiocarbazide formed by the action of phenyl-hydrazine on thiocarbamide. He states that it melts at 200-201". If it does and has the same percentage composition as our substance, it is probably an isomeride in which the phenyl radicle occupies a different position.We hope to settle this point by preparing some of this substance and comparing it with our own 554 NHGH, C o < ~ ~ . ~ ~ . ~ ~ -NH*NH-C,H, C o < ~ ~ - ~ ~ ~ ~ ~ ; SKINNER AND RUHEMANN THE ACTION OF Wine-red destroyed by ammonia and hydro-chloric acid. Violet colour ammonia makes it scarlet. Ferric chloride gives a red colour and an excess destroys it. Colour Reactions. NH, S < ~ ~ o ~ ~ ~ ~ ~ ; If a drop of dilute copper sulphate solution is added to a solution of any of these carbazides or semicarbazides an intense colorat,ion is produced. So intense and distinctive are these colorations that they may be used as qualitatire tests.The following colours are very characteristic :-A few drops of copper sulphate solution produce :-Deep blue not destroyed by ammonia. NH*C,H Green not destroyed by ammonia. A solution of copper sulphate added to monophenylcarbamide or monophenylthiocarbamide solution gives no colour reaction. Hence it follows that the production of the colour is characteristic of the substituting hydrazine-group which is necessary to form the carb-azide or semicarbazide. This colour is due to the oxidising action of copper sulphate for ot,her compounds of similar oxidising action produce colour reactions. Thus when mercuric chloride is added to diphenylcarbazide it acquires an intense violet colour very like that produced with copper sulphate. Pheny lurazole. When a mixture of biuret and phenylhydrazine is heated over a small flame ammonia is driven off and on cooling the whole mass solidifies.If this is extracted either with alcohol or with water, bundles of crystalline needles separate from the hot solution as it cools. After a second crystallisation from alcohol these have a melting point of 260". Their aqueous solution when treated with copper sulphate and potash does not give the " biuret reaction," but on adding potasli or ammonia a red coloration is produced. A determination of the nitrogen in these crystals gave 23.9 per cent. A compound of the formula CsH,N30 requires 23.72 per cent. of nitrogen. Such a substance has recently been prepared by Pinner (Ber. 20 2358) by heating one part of phenylhydrazine hjdrochlo-ride with one and a half parts of carbamide; his product had a melting point of 262" and it is therefore identical with ours.Thi PHENYLHYDRAZINE ON UREA. 555 substance which Pinner has named phenylurazole is formed in oui-reaction in the following way :-CO-NH H0N.H CO*NH = N H / 1 + 2NH:. ‘CO-NCsHS NH/ + I ‘CO-NH H.N*CsH5 I t s formation in this way from biuret suggests the idea t,hat in Pinner’s reaction biuret is first formed and it then produces the urazole by reacting with the phenylhydrazine. Diphenylcarbaxide Mercurochloride. An aqueous solution of mercuric chloride added to an alcoholic solution of the diphenylcarbazide gives at first a deep violet colour, and as the alcohol becomes more dilute a precipitate is formed. This precipitate is collected and recrystallised from hot alcohol.The crystals are flat plates which do not melt b u t decompose suddenly a t 135”. A drop of the alcoholic mother-liquor placed on filter-paper produces a deep violet stain. Analysis showed the crystalline substance to be a double compound of the composition CO(NH*NH-C6H5)z,HgClz. Found. Theory. 7- 7 r - w I. 11. 111. CIS - - 156 30.40 p. C. 31.04 H i d . 14 2.73 , 5-00 - 10.99 - N* 56 10.91 ,, 0 16 3-11 ,, Hg. 200 38.99 , - - -C1 - . 7 1 13-83 ,, - -- - -- 13-87 When this double compound is boiled with water in which it appears to be insoluble a liquid tarry substance is formed which floats on the surface and mercurous chloride falls t o the bottom. This viscons tmry substance on cooling becomes a brittle black solid which contains chlorine.It is soluble in alcohol and on addition of ammonia brings down a violet precipitate of the base which contains no chlorine. An excess of ammonia dissolves the coloured substance, whilst potash makes it red. The dry colour base is soluble in glacial acetic acid with a red coloration. Evidently then the action of mer-curic chloride is to oxidise the diphenylcarbazide to the hydrochloride of a colour base which is easily precipitated by ammonia. Pheqlhydrazine Parabanate. A solution of phenylhydrazine hydrochloride has no action on 556 SKINNER AND RUHEblAKN THE ACTION OF solution of parabanic acid but on adding sodium acetate to this mixture there is an immediate separation of crystalline leaves which analysis proves to be phenyl hydrazine parabanate.Evidently the reaction takes place quite simply ; thus :-C303N2H,,H,0 + 2CsHgN2,HC1 + 2NaC2H302 = C30sN2H,,2( CsH,N,)H20 + 2NaC1 + 2C2H402. The same substance may also be prepared by shaking a mixture of the free base with an aqueous solution of the acid. It is quite insoluble in alcohol and ether and melts at 170" with decomposition. When boiled with a very large quantity of water it dissolves and at the same time undergoes decomposition with formation of a hydrazide. The substance contains 1 mol. H,O just in the same way as parabanic acid does. We are inclined to consider this molecule as one of water of crystallisation. The formula C3O3N,H2,2 (C,H,N,),H,O of the substance dried at 100" requires the following values :-Found.Theory. r--A--7 r-- 7 I. 11. C15 . 180 51-73 p. c. 51-23 51.99 H, 20 5.73 , 5.50 5.80 - - NG 84 24.13 ,, 0 64 18.39 , - -Oxalzwhydraxide. When phenylhydrazine parabanate is boiled with a very large excess of water it dissolves slightly and on cooling a yellowish, ramiform crystalline substance separates. This is oxalurhydrazide. It is very slightly soluble in water quite insoluble in alcohol arid ether and melts with decomposition at 215". Th'e reaction takes place in the folloming manner :-NH* CO C 0 *N H*NH* C6H5 NH( C6H,Tli12)-c0 'NH( (&HEN,) *c 0 co/ I ,H,O = c o < ~ ~ 2 + HzO + CGHsN,. The substance reduces a copper sulphate solutioo with a green coloration. Our analysis gave the following numbers :-Found. Theory.1 I. 11. 7-HI,. 10 4.50 , 4.91 -- C9 . 108 48.64~. c. 48.24 N4 56 23.22 , - 25.11 0 3 . . . 48 2164 ,, . - PHENYLHYDRAZINE ON UREA. 557 An attempt was made to obtain this same substance from oxaluric acid. The latter was prepared from parabanic acid according to Liebig's directions ; it was then dissolved in watler and treated with sodium acetate and phenylhydrazine hydrochloride solutions. The crystalline silvery plates which immediately separated were collected and well washed with water. The analysis and comparison of this sub-stance with phenylhydrazine oxalate showed that they were identical, so that the following reaction takes place between oxnluric acid and phenylhydrazine hydrochloride :-NH*CooCooH + 2C6H,Nz,HC1 + 2NaCzH3O2 + H20 = c o < ~ ~ , Aniline hydrochloride in presence of sodium acetate gives with parabanic acid a reaction similar to that with phenylhydrazine hydro-chloride and produces aniline parabanate as a precipitate of slender needles ; these melt about 250" with decomposition.It may also be directly prepared by shaking aniline with an aqueous solution of parabanic acid. Pheiaylhydrazine-allsxan. The reaction between alloxan in aqueous solution and phenyl-hydrazine hydrochloride in presence of sodium acetate has lately been described by Pellizzari (Gazzetta 17 254). He has stated that the reaction takes place in the following was :-That is to say that the hydrazine reduces the alloxan to alloxantin, and this he explains by the supposition of the formation of an inter-mediate substance consisting of 2 mols.of alloxan and 1 mol. of phenylhydrazine but he has not isolated this substance. We found some time ago that this substance might be easily prepared by mixiag cold alcoholic solutions of alloxan and the free base ; in a short time a reaction begins and a substance is precipitated which is extremely unstable for if the vessel be slightly warmed an evolution of nitrogen begins. To pour the liquid on a filter-paper is sufficient to start its decomposition The determination of the composition of this substance by combustion appeared hopeless and so the following method was adopted. Experiments were made to find the quantity of free nitrogen which a definite weight of alloxan would give and they proved to our satisfaction that 1 mol. of alloxan yields 1 mol. o 558 EDELEANU SOME DERIVATIVES OF nitrogen ; it is probable therefore that the intermediate substance has the composition The alloxantin is formed by the reaction of this substance with the excess of alloxan thus :-i ' i ;N;H.C,H 5 j . Note on a Phenyl-piper?ll-thiocarbamide. This is a crystalline substance prepared by adding phenyl isothio-It is easily recrystallised from alcohol and exanate to piperidine. melts at 103-104". NH'C6H5 requires the following numbers :- NC5Hio The formula CS< Theory. r--7 r--h- -3 I. 11. C, - 144 65.45 per cent. 65.42 Hls 7-83 - 16 7-27 N . 28 12.72 , - 23-05 S 32 14.54 Found. - -University Laboratory Cnrnbridg e, March 1888