3 5-DIBROMO- AND 3 5-DICHLORO-PHENYLHYDRAZINE. 587 XLV I I I . 4 5-Dibromo- and 3 5-Dichloro-phenyl-JL yd raxine. By FREDERICK DANIEL CHATTAWAY and OSCAR CHARLES ELLINGTON. THESE hydrazines were prepared by the usual methods from the corresponding anilines. The anilines which are troublesome t o prepare in quantity were obtained by brominating or chlorinating pnitroaniline removing the amino-group from the 2 6-dihalogen-4-nitroaniline thus produced and reducing the 3 5-dihalogen-nitro-benzene thus : Hal/\lHal -. Hal{) Hal \/ NH*NH, \/ NH2 The 3 5-dihalogen-substituted phenylhydrazines resemble phenyl-hydrazine closely in behaviour are easily oxidised by air or oxidising agents giving m-dibromo- or m-dichloro-benzene react with halogen t o produce diazonium salts and yield with acid anhydrida and aldehydes stable and characteristic hydrazides and hydrazones 588 CHATTAWAY AND ELLINGTON : EXPERIMENTAL.3 5 - D i b ro m oph P 17 y 7 Ii y dr n z i I I e It y dr o c It 7 o rid P C,H 3B rz N 2H3 H C 1, was prepared by dissolving 3 5-dibromoaniline in a small quantity of glacial acetic acid adding concentrabd hydrochloric acid in excess and stirring vigorously until a thin pastel of the hydro-chloride was produced. This was then diazotised a t Oo and added to the calculated quantity of stannous chloride dissolved in concen-trated hydrochloric acid cooled to Oo. The 3 5-dibromophenyl'hydr-azine hydrochloride which separated as a cream-coloured paste was filtered off and crystallised from boiling dilute hydrochloric acid in which i t is moderately readily soluble separating in colourless, slender flattened prisms.On heating i t darkens in colour and decomposes without previ-ously melting a t about 207O: 0.2079 gave 0-3534 AgBr + AgC1. C1= 11.61 ; Br = 52.36. C6H7N2ClBr2 requires c1= 11.72 ; Br = 52.86 per cent. 3 5-Dibromophe~zyEhydrazi,te was obtained from the hydro-chloride by heating for a short time with excess of aqueous sodium hydroxidel. The hydrazine which solidified on cooling was crystal-lised from alcohol in which it is very readily soluble; it separated in colourless small elongated plates melting a t 95'5O : 0.1976 gave 0.2768 AgBr. Br = 59.61. C,H6N2Br requires Br = 60.14 per cent. It is slowly oxidised by the air and rapidly oxidised when heated with Fehling's solution or a solution of potassium chromate yielding nitrogen and m-dibromobenzene.It can only be preserved unchanged if sealed up and protected from light; if kept in a stoppered bottle exposed to light and air, it soon shows signs of decomposition. 3 5-Dichlorophenylhydruz~~~e hydrochloride which was prepared exactly as the dibromo-compound is moderately readily soluble in boiling dilute hydrochloric acid from which it crystallises in colourless small irregular plates. On heating these decompose without previously melting a t about 190° : 0.1602 gave 0.3207 AgCl. Cl=49-53. C6H7N,C1 requires c1= 49.84 per cent. 3 5-Dichlorophenylhydrazine crystallises from alcohol in which i t is very readily soluble in colourless small elongated plates melt-ing a t 1 1 8 O : 0.1912 gave 0'3056 AgC1.C1= 39.56. It quickly oxidises and turns brown in the air producing nitro-C6H6N,C12 requires C1= 40.06 per cent 3 5-DIBROMO- AND 3 5-DICHLORO-PHENYLEYDRAZINE. 589 gen and m-dichlorobenzene. The same action takes place quanti-tatively when it is oxidised by Fehling's solution or hot aqueous potassium chromate. The 3 5-dihalogen-substituted llydrazines readily form hydrazides when acetylated benzolated or heated with phthalic o r citraconic anhydride. -4 cetyl-3 5-dibroinopli en ylhydrazine C,H,Br,*NH-NH*CO*CH,, is very readily soluble in alcohol from which i t crystallises in slender colourless prisms melting a t 198*5O : 0.1920 gave 0.2341 AgBr. Br=51.89. C,H,ON,Br requires Br = 5 1.90 per cent. '4 cet?/l-3 5-dichloropheizyll~ydrazine crystallises from alcohol in which it is readily soluble in colourless slender flattened prisms melting a t 175'5O: 0.2259 gave 0.2948 AgC1.Benzoyl-3 5-dibromophenylhydrazirze, C1= 32.29. C,H80N,Cl requires C1= 32.38 per cent. C,H,Br,.NIl*NH.CO.C,H,, crystallises from alcohol in which it is readily soluble in slender, colourless plates melting a t 206O : 0.1478 gave 0.1492 AgBr. C,3H,,0N,Br2 requires Br = 43.20 per cent'. Renzoyl-3 5dichlorophenylhydrazi?ze crystallises from alcohol in which it is readily soluble in clusters of small colourless plates melting a t 221'5O: Br =42*95. 0.1918 gave 0.1946 AgCl. Cl=25-11. C1,R1,ON,CI2 requires Cl= 25.22 per cent. o-Nitrob enzoyl-3 5-di bromopherzylhydrasine crystallises from boil-ing alcohol o r glacial acetic acid in both of which it is moderately readily soluble giving pale yellow solutions in clusters of small, elongated very pale yellow plates melting a t 204O : 0.2036 gave 0.1840 AgBr.Br = 38.45. C,,H,O3N,Br requires Br = 38.51 per cent. o-ATitrob enzoyl-3 5-dichlorophenylhydrazine is moderat.ely readily soluble in boiling alcohol giving a bright yellow solution from which i t crystallises in slender very pale yellow elongated prisms melting a t 218.5O: 0,2118 gave 0.1855 AgC1. C,3H,0,N,C12 requires C1= 21-75 per cent. m-Nitrob enzoyl-3 5dibromophenylhydraaine is sparingly soluble in boiling alcohol giving a pale yellow-coloured solution from which i t crystallises in very faintly yellow-coloured slender prisms melting a t 235O: C1= 21.68 590 CBATTAWAP AND ELLINGTON: 0.1688 gave 0.1534 AgBr.Br = 38.66. C13H,0,N3Br2 require? Br = 38.5 1 per cent. m-Xitrob enzoyl - 3 5 - dichlorophenylhydr~z~?~e crystallises from alcohol in which it is sparingly soluble in long slender pale yellow prisms melting a t 235'5O: 0.2872 gave 0.2508 AgCl. C1=21.60. C13E,03N3C1 requires C1= 21.75 per cent. p-Nitro be~oyl-3 5-dibromophenylhydrazine is sparingly soluble in alcohol and moderatlely readily so in boiling glacial acetic acid, from which it crystallises in tufts of bright yellow very slender prisms melting a t 200O: 0.1150 gave 0.1039 AgBr. C,3H903N3Br requires Br = 38.51 per cent. p-Nitrob enzoyl-3 5-dichlorophenylhydrazi.ne is sparingly soluble in alcohol and readily so in boiling glacial acetic acid from which it crystallises in pale yellow very slender hair-like prisms melting a t 196O: Br = 38.44.02082 gave 0.1828 AgC1. C1=21*72. Citracon yl-3 5dibromophenyEhydrazide, C"13H903N3Cl requires C1= 21.75 per cent. CO$H COO CMe' C,H,Br,* NH *N< i s readily soluble in benzene from which it crystallises in compact, bright yellow prisms melting a t 155O: 0'2595 gave 0.2706 AgBr. Br = 44.36. Cl1H8O2N,Br requires Br = 44.39 per cent, Citraconyl-3 5-dichlorophenylhydrazide crystallises from alcohol or benzene in both of which it is very readily soluble in bright yellow compact prisms with domed ends melting a t 156.5O : 0.2202 gave 0.2310 AgCl. C1=25*95. The 3 5-dihalogen-substituted phenylhydrazims yield with alde-hydes a r d ketones stable well-crystallised hydrazones.They are as a rule easily prepared by mixing an alcoholic solution of the hydrazine with an alcoholic solution of the equivalent amount of the correspmding aldehyde or ketone and adding a little glacial acetic acid which appears much to facilitate the reaction. Cl,H80,N2C1 requires c'l= 26'16 per cent. Benzalde hyde-3 5-dichlorophenylh ydrazone, C,H,Cl,*NH-N:CHPh, crystallises from alcohol in which it is readily soluble giving a very pale yellow solution in stout, rhombic very faint yellow plates melting a t 117'5O 0.2130 gave 0-2294 AgCl. C1= 26.64. C,,H,,N2C1 requires C1= 26.75 per cent. When exposed t o light it quickly becomes bright scarlet which may be due to rearrangement of the molecule to an azo-configura-tion : C6H,C1,*NH* N :CHPh + C,H,Cl,-N :N* CH,P h , a rearrangement which has been suggested as an explanation of the striking change) of colour which the unsubstituted hydrazone undergoes when similarly exposed t o light.o-Nit rob ensaldehyde-3 ; 5-dibrom oph e nylhydrazone is moderately readily soluble in boiling glacial acetic acid from which i t crystal-lisea in long bright scarlet needle-shaped flattened prisms melting and decomposing at 234O: 0.2111 gave 0.1983 AgBr. Br=39*98. Cl3HgO2N3Br2 requires Br = 40.05 per cent. o-Nitrobeusaldehyde - 3 5 - dichlorophenylhy~razolze crystallises from alcohol in which i t is moderately readily soluble in bright scarlet very small slender prisms melting at 222O: 0.2568 gave 0.2316 AgCl.C,,H,O,N,Cl requires C1= 22.87 per cent. m-nitrob elisaldehyde-3 5-dibromophe?aylhydrazo?ze is very spar-ingly soluble in boiling glacial acetic acid giving a bright yellow solution froin which i t crystallises in clusters of bright orange-coloured very small flattened prisms melting a t 233O: 0.2437 gave 0.2292 AgBr. C13H,02N3Br2 requires Br = 40.05 per cent I m-NitrobeiaxaldeiLyde-3 5-dichloroyhenyli~ydrazo?ae is very spar-ingly soluble in boiling glacial acetic acid giving a bright yellow solution from which it crystallises in clusters of minute flattened, bright oxange prisms melting a t 205O: C1= 22.32. Br =40*03. 0.4124 gave 0.3780 AgCl. C,,Hg0,N,C12 requires C1= 22-87 per cent. p-Nitrobenzaldehyde-3 5-dibrornophenylhydrazone exists in two polymorphous modifications.It is sparingly soluble in boiling glacial aoetic acid giving a bright orange coloured solution from which it crystallises on rapidly cooling in long slender orange-coloured prisms ; small irregular six-sided red plates melting a t 242O soon make their appearance in the liquid and grow a t the expense of the orange-coloured modification which dissolves and finally disappears. C1= 22.69. 0.2436 gave 0.2293 AgBr. Br=40*05. p-Nitrob enzaldehyde-3 5-dichlorophenylhydrazone also exists in VOL. CIX. A A G13H,02N,Br2 requires Br = 40-05 per cent 592 S 5-DIBROMO- AND 3 5-DICHLORO-PHENYLHYDRAZINE. two polymorphous modifications. It is sparingly soluble in boiling glacial acetic acid giving a bright orangecoloured solution from which i t crystallises in long slender orange-coloured prisms which similarly transform into clusters of minute scarlet six-sided plates melting a t 238.5O: 0.1884 gave 0.1735 AgC1.C1= 22.79. C,,R,O,N,Cl requires C1= 22.87 per cent. Sa.licyla7dehyde-3 5dibromophenylhydraaone is very readily soluble in slcohol from which it crystallises in pale yellow plates melting a t 141'5O: 0-2111 gave 0.2137 AgBr. Br=43*07. Cl3H1,ON2Br2 requires Br = 43.30 per cent. Salicyla7dehyde-3 5-dichlorophenylhydrazone crystallises from alcohol in which it is very readily soluble in glistening very faint yellow platies melting a t 146O : 0-2309 gave 0-2350 A@. C1=25*19. C13H,,0N2C12 requires C1= 25.23 per cent. ,4ni~uEdehyde-3 5-dibromophenylhydraaone is very readily soluble in boiling alcohol from which it crystallises in colourless prisms melting a t 130O: 0.2296 gave 0.2243 AgBr.C,,Hi20N,Br2 requires Br = 41.62 per cent. A &aldehyde-3 5d~chEorophenyEhydrazo~ae crystallises from boil-ing alcohol in which i t is readily soluble in clusters of very slender, colourless prisms melting a t 127O : Br = 41.58. 0.2250 gave 0.2179 AgC1. Cinnarnaldehyde-3 5-dibromophenylhydrazone, C1= 23'97. C1,H120N,C12 requires C1= 24.03 per cent. C,H,Br,*NH*N CH* CH :CHP h, is fairly readily soluble in boiling alcohol giving a bright yellow solution from which it crystallises in glistening yellow plates melt-ing a t 150O: 0.1654 gave 0.1624 AgBr. Br=41*79. Cin nu malde h yd e-3 5 d i c hloroph e n yl h ydrazone C,,Hi,N2Br2 requires Br= 42.06 per cent.cr ystallises from boiling alcohol in which it is very readily soluble .giving a bright yellow solution in pale yellow long flattened prisms melting a t 142O : 0.2348 gave 0.2302 AgC1. The 3 Sdibromophenylhydrazone of pyruvic acid, Cd = 24-25. Ci,H1,N2CTl2 requires C1= 24.36 per cent. C,H3Br2-NH*N CMe*CO,H is very readily soluble in alcohol from which it crystallises in verj pale yellow almost colourless prisms melting and decomposing a t 192O : 0-2454 gave 0.2739 AgBr. C,HB0,N2Br2 requires Br = 47.57 per cent. The 3 5-dichlol-ophenylhydrazone of pyruvic acid crystallises from alcohol in which it is very readily soluble in very pale yellow, slender prisms melting a t 192O: Br = 47.49. 0.1970 gave 0.2276 AgC1.C1= 28.59-C,H,O,N,Cl requires C1= 28.70 per cent. UNIVERSITY CHEMICAL LABORATORY, OXFORD. [Received April 24h 1916. 3 5-DIBROMO- AND 3 5-DICHLORO-PHENYLHYDRAZINE. 587 XLV I I I . 4 5-Dibromo- and 3 5-Dichloro-phenyl-JL yd raxine. By FREDERICK DANIEL CHATTAWAY and OSCAR CHARLES ELLINGTON. THESE hydrazines were prepared by the usual methods from the corresponding anilines. The anilines which are troublesome t o prepare in quantity were obtained by brominating or chlorinating pnitroaniline removing the amino-group from the 2 6-dihalogen-4-nitroaniline thus produced and reducing the 3 5-dihalogen-nitro-benzene thus : Hal/\lHal -. Hal{) Hal \/ NH*NH, \/ NH2 The 3 5-dihalogen-substituted phenylhydrazines resemble phenyl-hydrazine closely in behaviour are easily oxidised by air or oxidising agents giving m-dibromo- or m-dichloro-benzene react with halogen t o produce diazonium salts and yield with acid anhydrida and aldehydes stable and characteristic hydrazides and hydrazones 588 CHATTAWAY AND ELLINGTON : EXPERIMENTAL.3 5 - D i b ro m oph P 17 y 7 Ii y dr n z i I I e It y dr o c It 7 o rid P C,H 3B rz N 2H3 H C 1, was prepared by dissolving 3 5-dibromoaniline in a small quantity of glacial acetic acid adding concentrabd hydrochloric acid in excess and stirring vigorously until a thin pastel of the hydro-chloride was produced. This was then diazotised a t Oo and added to the calculated quantity of stannous chloride dissolved in concen-trated hydrochloric acid cooled to Oo. The 3 5-dibromophenyl'hydr-azine hydrochloride which separated as a cream-coloured paste was filtered off and crystallised from boiling dilute hydrochloric acid in which i t is moderately readily soluble separating in colourless, slender flattened prisms.On heating i t darkens in colour and decomposes without previ-ously melting a t about 207O: 0.2079 gave 0-3534 AgBr + AgC1. C1= 11.61 ; Br = 52.36. C6H7N2ClBr2 requires c1= 11.72 ; Br = 52.86 per cent. 3 5-Dibromophe~zyEhydrazi,te was obtained from the hydro-chloride by heating for a short time with excess of aqueous sodium hydroxidel. The hydrazine which solidified on cooling was crystal-lised from alcohol in which it is very readily soluble; it separated in colourless small elongated plates melting a t 95'5O : 0.1976 gave 0.2768 AgBr.Br = 59.61. C,H6N2Br requires Br = 60.14 per cent. It is slowly oxidised by the air and rapidly oxidised when heated with Fehling's solution or a solution of potassium chromate yielding nitrogen and m-dibromobenzene. It can only be preserved unchanged if sealed up and protected from light; if kept in a stoppered bottle exposed to light and air, it soon shows signs of decomposition. 3 5-Dichlorophenylhydruz~~~e hydrochloride which was prepared exactly as the dibromo-compound is moderately readily soluble in boiling dilute hydrochloric acid from which it crystallises in colourless small irregular plates. On heating these decompose without previously melting a t about 190° : 0.1602 gave 0.3207 AgCl. Cl=49-53. C6H7N,C1 requires c1= 49.84 per cent.3 5-Dichlorophenylhydrazine crystallises from alcohol in which i t is very readily soluble in colourless small elongated plates melt-ing a t 1 1 8 O : 0.1912 gave 0'3056 AgC1. C1= 39.56. It quickly oxidises and turns brown in the air producing nitro-C6H6N,C12 requires C1= 40.06 per cent 3 5-DIBROMO- AND 3 5-DICHLORO-PHENYLEYDRAZINE. 589 gen and m-dichlorobenzene. The same action takes place quanti-tatively when it is oxidised by Fehling's solution or hot aqueous potassium chromate. The 3 5-dihalogen-substituted llydrazines readily form hydrazides when acetylated benzolated or heated with phthalic o r citraconic anhydride. -4 cetyl-3 5-dibroinopli en ylhydrazine C,H,Br,*NH-NH*CO*CH,, is very readily soluble in alcohol from which i t crystallises in slender colourless prisms melting a t 198*5O : 0.1920 gave 0.2341 AgBr.Br=51.89. C,H,ON,Br requires Br = 5 1.90 per cent. '4 cet?/l-3 5-dichloropheizyll~ydrazine crystallises from alcohol in which it is readily soluble in colourless slender flattened prisms melting a t 175'5O: 0.2259 gave 0.2948 AgC1. Benzoyl-3 5-dibromophenylhydrazirze, C1= 32.29. C,H80N,Cl requires C1= 32.38 per cent. C,H,Br,.NIl*NH.CO.C,H,, crystallises from alcohol in which it is readily soluble in slender, colourless plates melting a t 206O : 0.1478 gave 0.1492 AgBr. C,3H,,0N,Br2 requires Br = 43.20 per cent'. Renzoyl-3 5dichlorophenylhydrazi?ze crystallises from alcohol in which it is readily soluble in clusters of small colourless plates melting a t 221'5O: Br =42*95.0.1918 gave 0.1946 AgCl. Cl=25-11. C1,R1,ON,CI2 requires Cl= 25.22 per cent. o-Nitrob enzoyl-3 5-di bromopherzylhydrasine crystallises from boil-ing alcohol o r glacial acetic acid in both of which it is moderately readily soluble giving pale yellow solutions in clusters of small, elongated very pale yellow plates melting a t 204O : 0.2036 gave 0.1840 AgBr. Br = 38.45. C,,H,O3N,Br requires Br = 38.51 per cent. o-ATitrob enzoyl-3 5-dichlorophenylhydrazine is moderat.ely readily soluble in boiling alcohol giving a bright yellow solution from which i t crystallises in slender very pale yellow elongated prisms melting a t 218.5O: 0,2118 gave 0.1855 AgC1. C,3H,0,N,C12 requires C1= 21-75 per cent. m-Nitrob enzoyl-3 5dibromophenylhydraaine is sparingly soluble in boiling alcohol giving a pale yellow-coloured solution from which i t crystallises in very faintly yellow-coloured slender prisms melting a t 235O: C1= 21.68 590 CBATTAWAP AND ELLINGTON: 0.1688 gave 0.1534 AgBr.Br = 38.66. C13H,0,N3Br2 require? Br = 38.5 1 per cent. m-Xitrob enzoyl - 3 5 - dichlorophenylhydr~z~?~e crystallises from alcohol in which it is sparingly soluble in long slender pale yellow prisms melting a t 235'5O: 0.2872 gave 0.2508 AgCl. C1=21.60. C13E,03N3C1 requires C1= 21.75 per cent. p-Nitro be~oyl-3 5-dibromophenylhydrazine is sparingly soluble in alcohol and moderatlely readily so in boiling glacial acetic acid, from which it crystallises in tufts of bright yellow very slender prisms melting a t 200O: 0.1150 gave 0.1039 AgBr.C,3H903N3Br requires Br = 38.51 per cent. p-Nitrob enzoyl-3 5-dichlorophenylhydrazi.ne is sparingly soluble in alcohol and readily so in boiling glacial acetic acid from which it crystallises in pale yellow very slender hair-like prisms melting a t 196O: Br = 38.44. 02082 gave 0.1828 AgC1. C1=21*72. Citracon yl-3 5dibromophenyEhydrazide, C"13H903N3Cl requires C1= 21.75 per cent. CO$H COO CMe' C,H,Br,* NH *N< i s readily soluble in benzene from which it crystallises in compact, bright yellow prisms melting a t 155O: 0'2595 gave 0.2706 AgBr. Br = 44.36. Cl1H8O2N,Br requires Br = 44.39 per cent, Citraconyl-3 5-dichlorophenylhydrazide crystallises from alcohol or benzene in both of which it is very readily soluble in bright yellow compact prisms with domed ends melting a t 156.5O : 0.2202 gave 0.2310 AgCl.C1=25*95. The 3 5-dihalogen-substituted phenylhydrazims yield with alde-hydes a r d ketones stable well-crystallised hydrazones. They are as a rule easily prepared by mixing an alcoholic solution of the hydrazine with an alcoholic solution of the equivalent amount of the correspmding aldehyde or ketone and adding a little glacial acetic acid which appears much to facilitate the reaction. Cl,H80,N2C1 requires c'l= 26'16 per cent. Benzalde hyde-3 5-dichlorophenylh ydrazone, C,H,Cl,*NH-N:CHPh, crystallises from alcohol in which it is readily soluble giving a very pale yellow solution in stout, rhombic very faint yellow plates melting a t 117'5O 0.2130 gave 0-2294 AgCl. C1= 26.64.C,,H,,N2C1 requires C1= 26.75 per cent. When exposed t o light it quickly becomes bright scarlet which may be due to rearrangement of the molecule to an azo-configura-tion : C6H,C1,*NH* N :CHPh + C,H,Cl,-N :N* CH,P h , a rearrangement which has been suggested as an explanation of the striking change) of colour which the unsubstituted hydrazone undergoes when similarly exposed t o light. o-Nit rob ensaldehyde-3 ; 5-dibrom oph e nylhydrazone is moderately readily soluble in boiling glacial acetic acid from which i t crystal-lisea in long bright scarlet needle-shaped flattened prisms melting and decomposing at 234O: 0.2111 gave 0.1983 AgBr. Br=39*98. Cl3HgO2N3Br2 requires Br = 40.05 per cent. o-Nitrobeusaldehyde - 3 5 - dichlorophenylhy~razolze crystallises from alcohol in which i t is moderately readily soluble in bright scarlet very small slender prisms melting at 222O: 0.2568 gave 0.2316 AgCl.C,,H,O,N,Cl requires C1= 22.87 per cent. m-nitrob elisaldehyde-3 5-dibromophe?aylhydrazo?ze is very spar-ingly soluble in boiling glacial acetic acid giving a bright yellow solution froin which i t crystallises in clusters of bright orange-coloured very small flattened prisms melting a t 233O: 0.2437 gave 0.2292 AgBr. C13H,02N3Br2 requires Br = 40.05 per cent I m-NitrobeiaxaldeiLyde-3 5-dichloroyhenyli~ydrazo?ae is very spar-ingly soluble in boiling glacial acetic acid giving a bright yellow solution from which it crystallises in clusters of minute flattened, bright oxange prisms melting a t 205O: C1= 22.32.Br =40*03. 0.4124 gave 0.3780 AgCl. C,,Hg0,N,C12 requires C1= 22-87 per cent. p-Nitrobenzaldehyde-3 5-dibrornophenylhydrazone exists in two polymorphous modifications. It is sparingly soluble in boiling glacial aoetic acid giving a bright orange coloured solution from which it crystallises on rapidly cooling in long slender orange-coloured prisms ; small irregular six-sided red plates melting a t 242O soon make their appearance in the liquid and grow a t the expense of the orange-coloured modification which dissolves and finally disappears. C1= 22.69. 0.2436 gave 0.2293 AgBr. Br=40*05. p-Nitrob enzaldehyde-3 5-dichlorophenylhydrazone also exists in VOL. CIX. A A G13H,02N,Br2 requires Br = 40-05 per cent 592 S 5-DIBROMO- AND 3 5-DICHLORO-PHENYLHYDRAZINE.two polymorphous modifications. It is sparingly soluble in boiling glacial acetic acid giving a bright orangecoloured solution from which i t crystallises in long slender orange-coloured prisms which similarly transform into clusters of minute scarlet six-sided plates melting a t 238.5O: 0.1884 gave 0.1735 AgC1. C1= 22.79. C,,R,O,N,Cl requires C1= 22.87 per cent. Sa.licyla7dehyde-3 5dibromophenylhydraaone is very readily soluble in slcohol from which it crystallises in pale yellow plates melting a t 141'5O: 0-2111 gave 0.2137 AgBr. Br=43*07. Cl3H1,ON2Br2 requires Br = 43.30 per cent. Salicyla7dehyde-3 5-dichlorophenylhydrazone crystallises from alcohol in which it is very readily soluble in glistening very faint yellow platies melting a t 146O : 0-2309 gave 0-2350 A@.C1=25*19. C13H,,0N2C12 requires C1= 25.23 per cent. ,4ni~uEdehyde-3 5-dibromophenylhydraaone is very readily soluble in boiling alcohol from which it crystallises in colourless prisms melting a t 130O: 0.2296 gave 0.2243 AgBr. C,,Hi20N,Br2 requires Br = 41.62 per cent. A &aldehyde-3 5d~chEorophenyEhydrazo~ae crystallises from boil-ing alcohol in which i t is readily soluble in clusters of very slender, colourless prisms melting a t 127O : Br = 41.58. 0.2250 gave 0.2179 AgC1. Cinnarnaldehyde-3 5-dibromophenylhydrazone, C1= 23'97. C1,H120N,C12 requires C1= 24.03 per cent. C,H,Br,*NH*N CH* CH :CHP h, is fairly readily soluble in boiling alcohol giving a bright yellow solution from which it crystallises in glistening yellow plates melt-ing a t 150O: 0.1654 gave 0.1624 AgBr. Br=41*79. Cin nu malde h yd e-3 5 d i c hloroph e n yl h ydrazone C,,Hi,N2Br2 requires Br= 42.06 per cent. cr ystallises from boiling alcohol in which it is very readily soluble .giving a bright yellow solution in pale yellow long flattened prisms melting a t 142O : 0.2348 gave 0.2302 AgC1. The 3 Sdibromophenylhydrazone of pyruvic acid, Cd = 24-25. Ci,H1,N2CTl2 requires C1= 24.36 per cent. C,H3Br2-NH*N CMe*CO,H is very readily soluble in alcohol from which it crystallises in verj pale yellow almost colourless prisms melting and decomposing a t 192O : 0-2454 gave 0.2739 AgBr. C,HB0,N2Br2 requires Br = 47.57 per cent. The 3 5-dichlol-ophenylhydrazone of pyruvic acid crystallises from alcohol in which it is very readily soluble in very pale yellow, slender prisms melting a t 192O: Br = 47.49. 0.1970 gave 0.2276 AgC1. C1= 28.59-C,H,O,N,Cl requires C1= 28.70 per cent. UNIVERSITY CHEMICAL LABORATORY, OXFORD. [Received April 24h 1916.