[CONTRIBUTION FROM THE
RESEARCH LABORATORIES OF RALPHL . EVANS AssocIAmS]
N-SUBSTITUTED ETHYLENEDIAMINES FRED LINSKER
AND
RALPH L. EVANS
Received March 18, lQ&
The action of ethylenediamine on active halogen compounds such as 0- and p-chloronitrobenzene has received but little attention. Of the possible condensation products only two have been described. N ,N'-di-(0-nitropheny1)ethylenediamine was obtained by Jedlicka (1) in 16% yield by condensation of o-bromonitrobenzene with 75% ethylenediamine. The condensation was effected by heating the mixture in a sealed tube a t 120-130" for eight hours. Borsche and Titsingh (2) isolated a trace of the same compound from the reaction of o-nitroaniline with ethylene bromide. N-(o ,p-dinitropheny1)ethylenediamine and N ,N'-di-(o ,p-dinitropheny1)ethylenediamine were recently obtained by Quin and Robinson (3) through a condensation in alcoholic medium. We were able to condense o-chloronitrobenzene with 95% ethylenediamine under milder conditions than those employed by Jedlicka and found that the yield of di-(o-nitropheny1)ethylenediaminecan be doubled when CuC12 is added as a catalyst. Using a larger excess of ethylenediamine, N-(0-nitropheny1)ethylenediamine was obtained in 70% yield. It was easily reduced by stannous chloride in hydrochloric acid to the corresponding N-(0-aminopheny1)ethylenediamine. Both these compounds were found to be water-soluble. The nitro group of the former supresses the basicity of the secondary aromatic amino
111
0
4
IV NHCHzCHaNH2
3
H
/=-7NHCH2CHpNH~
IN\-/
V
VI
group; hence dilute HC1 forms the monohydrochloride whereas the reduced base gives the trihydrochloride. The condensation of p-nitrochlorobenzene with ethylenediamine occurs in a manner analogous to the ortho-compound with a 27% yield of N,N'-di-(pnitropheny1)ethylenediamine and a 55% yield of N-(pnitropheny1)ethylenediamine. EXPERIMENTAL
Melting points are uncorrected. N, N'-di-(0-nitrophenyl)ethylenediamine(I). Five grams of anhydrous CuCll was dissolved in 80 g. of ethylenediamine (95%) in a 2-1.3-neck flask and 100 g. of o-chloronitroben283
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FRED LINSKER AND RALPH L. EVANS
sene added t o the dark blue 13olution. The mixture was stirred mechanically and heated under reflux to 110'. An exothermic reaction started and kept the mixture boiling for fifteen minutes. Heating was continued under reflux until the mixture solidified. After cooling, 1 liter of water was added and the residual yellow solid filtered off, washed with 200 cc. of water and dried in vacuo. The dry residue was extracted repeatedly with boiling benzene and on cooling of the combined benzene extracts a fairly pure product was obtained. Yield 30% (47 g.), m.p. 185"; recrystallized from benzene, m.p. 188" [lit. (1) 189-190"]. N-(0-nitrophenyl)elhylenedzamine (11). To a solution of 10 g. of anhydrous CuClz in 160 g. of ethylenediamine, 100 g. of o-chloronitrobenzene was added and the mixture was heated with mechanical stirring under efficient reflux. Above 100" a vigorous reaction set in and without application of external heat the mixture boiled for ten minutes. Heating t o reflux temperature was continued in an oil-bath for three hours. Some water and the excess ethylenediamine were removed by distillation under reduced pressure and the residual solid crystallized from 700 cc. of dilute hydrochloric acid (1:5). It was dried over NaOH pellets. Yield 70% (102 g.) m.p. 262' (dec.), yellow needles, soluble in HzO, insoluble in dilute HCl. Anal. Calc'd for C ~ H t l N ~ O ~ ~ C, I I C44.14; l : H , 5.52; C1, 16.32. Found: C, 43.94; H , 5.53; C1, 16.51. Caustic soda converts the hydrochloride into the free base, which is readily soluble in water. N-(o-aminophenyl)ethylenetEiamine (Ill). Eighty grams of N-(o-nitropheny1)ethylenediamine hydrochloride waa suspended in 240 cc. of 95% ethanol and a solution of 46Qg. of cryst. SnClz in 420 cc. of conc'd HCl added. After the initial reaction had subsided, the mixture was heated on the steam-bath for thirty minutes. The resulting solution was kept in the refrigerator overnight and the crystallized Sn double-salt of the base was filtered. It was dissolved in 500 cc. of water and HeS was passed through the solution until the precipitation of the tin sulfides was completed. The tin-free filtrate was evaporated to dryness on the steam-bath. Forty-seven grams of the trihydrochloride was obtained. It was recrystallized from conc'd HCl and dried a t 100' over NaOH pellets in the Abderhalden pistol; colorless prisms, soluble in water, insoluble in ethanol, m.p. 211" (dec.). Anal. Calc'd for CaHlrN1.3HC1: C, 36.85; H, 6.14; C1, 40.85. Found: C, 36.97; €I, 6.45; C1, 40.70. The free base was precipitahed from the concentrated aqueous solution of the trihydrochloride by addition of alkali. It forms an oily liquid and is soluble in water, ethanol, benzene, and chloroform, sparingly soluble in ether. N ,N'-di-(p-nitrophenyZ)eth?jZenediamine(ZV). Five grams of CuCle was dissolved in 80 g. of ethylenediamine and 150 g. of p-chloronitrobenzene added. The mixture was heated under reflux until reaction started and heating continued for an additional three hours. After cooling, the solidified product was stirred with 1 liter of water and filtered. The insoluble residue was washed with water and dried over CaClz;yield 41 g. Recrystallized from nitrobenzene, needles, m.p. 215" [lit. (1) 216'1 were obtained. N-(p-nitrophenyZ)ethyZenediamine ( V ) . One hundred grams of p-chloronitrobenzene waa addea to a solution of 10 g. of CuClz in 160 g. of ethylenediamine (95%) and the mixture heated under reflux until the reaction set in. Heating was continued for three hours. After cooling, 1 liter of water was added, stirred 15 minutes, and filtered. The precipitate was recrystallized from boiling wiiter and dried over CaClZ;yield 66 g., yellow prisms, m.p. 152". The compound dissolves ir dilute mineral acids, alcohol, hot water, and hot benzene. It is only sparingly soluble in ether, benzene, and water at room temperature. Anal. Calc'd for CaHl1NsOe: C, 53.03; H , 6.08. Found: C, 53.23; H, 6.24. N - (p-aminophenyZ)ethyZenediamine (VI). Sixty-five grams of N- (p-nitropheny1)ethylenediamine was suspended in 200 cc. of ethanol and a solution of 380 g. of cryst. SnClpin 350 cc. of conc'd HC1 added. The reaction was completed by warming on the steam-bath for 30 minutes. A solution was obtained which deposited the tin double-salt of the amine on standing overnight a t 0". This was filtered, dissolved in water, and decomposed as in the
N-SUBSTITUTED ETHYLENEDIAMINES
285
case of the o-compound. Fifty-nine grams of trihydrochloride w t t ~obtained. It was purified by adding methanol conc'd HC1 t o its concentrated aqueous solution; colorless prisms, m.p. 284" (dec.). Anal. Calc'd for CsH1,N,.3HCI: C, 36.85; H, 6.14; C1, 40.85. Found: C, 36.56; H, 6.39; C1, 40.70. The trihydrochloride is soluble in water and ethanol. Excess alkali precipitates t h e free base as oil. The latter is soluble in water, ethanol, and chloroform, insoluble in benzene and ether.
+
SUMMARY
1. 0- and p-Chloronitrobenzene were condensed with ethylenediamine in the presence of CuClz in an open system. 2. Mono- and di-substituted ethylenediamines were obtained depending upon the ratio of starting materials used. 3. Reduction of the N-(nitropheny1)ethylenediamines yielded the corresponding triamines. New YOBK,N. Y. REFERENCES (1) JEDLICICA, J . prakt. Chem. ( N . S . ) ,48, 193 (1893). (2) BORSCHE m~TITSINGH, Ber., 40, 5013 (1907). (3) QUIN AND ROBINSON, J . Chem. SOC.,555 (1943).
