FRANCIS H. CASE
3994
Vol. 70
Acidification t o PH 4 yielded 0.92 g., m. p. 122.4-122.7'. Nitroguanidine with Methyl Sulfate.-Fowr grams This 79% yield was crystallized three times fromohotmetha- (0.038 mole) of nitroguanidine was heated at 73" for nol (3.3 cc. per gram) t o melt a t 124.8-125.7 A nega- twenty-two hours in a large excess of dimethyl sulfate (25 tive Franchimont test was obtained with diethylaniline. cc.) The clear solution was drowned in 100 cc. of water Anal. Calcd. for C ~ H U N B OC, ~ : 30.8; H,6.06; N, and the unused dimethyl sulfate was decomposed with 40 cc. of 20% sodium hydroxide solution which gave a final 36.0. Found: C, 30.7; H, 6.22; N, 35.5. This material was recovered unchanged after its alkaline PH of 8. This solution was extracted continuously with combined ether extracts, which contained solution at 50" was treated with 5 equivalents of sodium ether. 50The cc. of water, were distilled in V ~ C U O(12 mm.). nitrite and then acidified to pH 4 over twenty minutes about with aqueous hydrochloric acid. It was also not changed The aqueous distillate on cooling in an ice-water-bath gave needle-like crystals. These crystals melted a t 56by treatment with acetic anhydride-acetic acid at 25" over long 57" and did not depress the melting point of a known twelve hours. When this acetylation mixture was heated sample of dimethylnitramine (m. p. 58-57'), yield 250 t o 8C-90°, gas was evolved over three hours and no solid product could be recovered. Likewise, no solid could be mg. (7.2%). Summary recovered after treatment wi:h sodium acetate and acetyl chloride in acetic acid at 25 ; gas was evolved. On the 1. Although 2-nitraminoA2- 1,3-diazacycloother hand. at least 50% of the l-nitro-2-~ro~vlamino-2nitraminoimidazolidine was recovered after-treatment with pentene, -cyclohexene and -cycloheptene can be benzoyl chloride in aqueous alkali a t 4-20 converted to the corresponding 1,3-dinitro-1,3-diSilver Nitroguanidine with Methyl Iodide.-Thiele'slO azacyclopentanone-2, -cyclohexanone-2 and -cyprocedure wasised in the preparation of the silver salt of nitroguanidine used in this experiment, the only variation cloheptanone-2, only the first of the nitramines being that ammonium hydroxide was used in place of bar- gave a cyclic N,N1-dinitroguanidine. ium hydroxide:. 2. This nitration is unique among disubstiA large excess, 18.2 g. (0.128 mole), of methyl iodide was tuted acylic or cyclic guanidines, and may be added t o a susuension of 2 E. (0.0095 mole) of the silver salt of nitroguanidine in 10 6c. of absolute ethanol. This owing to the enforced planarity of the diazacyclomixture was left a t room temperature for seven days after pentene ring. which a dense yellow precipitate had formed. The pre3. Addition products comprising ethanol, procipitate was removed from the solution by filtration and ex- panol, ammonia, propylamine and dibutylamine tracted with 20 cc. of hot methanol. 1-nitro-2-nitramino- A2-imidazoline are The original filtrate on evaporation t o dryness left a with small amount of reddish-brown residue (ca. 15 mg.) which thought t o be imidazolidines resulting by saturacontained silver. tion of the imido double bond. They do not, howThe methanol extract on cooling t o room temperature ever, undergo reactions expected of the secondary deposited 0.12 g. of crystals which melted at 243' with decomposition. A mixed melting point determination with amino group which would be produced by such a n authentic sample of nitroguanidine established the saturation. identity of these crystals. The yield was 120 mg. A furThe primary nitramino group in nitroguanidines ther 0.32 g. of nitroguanidine was obtained by extracting is shown to be abnormal in that i t cannot be althe yellow solid with 35 cc. of boiling water. The total recovery of nitrnguanidine 'was not over 0.49 g. (calculated kylated nor does i t respond in the Franchimont from the solubility of nitroguanidine in water a t 18") or test which is characteristic for aliphatic alkylnitra49.4% by theory. mines. -TORONTO, ONTARIO RECEIVED MAY24, 1948 (10) Thiele, Ann., 270, 1 (1S92).
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[CONTRIBUTION FROM
THE
CHEMISTRY DEPARTYEST
OF
TEMPLE L1NIVERSITP]
Substituted 1 ,lo-Phenanthrolines. I. The Synthesis of Certain Mono- and Polymethyl- 1,lO-phenanthrolines' BY FRANCIS H. CASE
In 1944 Smith and Richter2measured the oxidation potentials of the ferrous complexes of various
1
5- and &substituted 1,lO-phenanthrolines. It was found that, whereas, substitution of a nitro group in the 5- position of 1,lO-phenanthroline (I) raises this potential, the opposite effect is observed when the methyl radical is the substituent. (1) Presented before the Organic Division at the h'ew York Meeting of the American Chemical Society, September, 1947. (2) Smith and Richter, I n d . Eng. Chcm.. A n d . Ed., 16, 580 f
1944)
With the idea of producing a substituted phenanthroline the oxidation potential of whose ferrous complex would be lower than any of those now dvailable, a number of mono-, di-, tri- and tetramethyl-1,lO-phenanthrolines have been synthesized in which the methyl radicals are substituted in the nitrogen-containing rings as well as in the central nucleus. The preparation of 5,6-dimethyl-l, 10-phenanthroline was carried out by the following series of reactions: 3,4-dimethylaniline (11) was nitrated to yield 2-nitro-4,5-dimethylaniline (111). The procedure described for the nitration is much simpler than that previously r e ~ o r d e d . ~By the Skraup reaction 111 was converted to 5,Ci-di(3) Nndting Brown and Thesmnr
Hp7
34. ? 2 L X ( I W l l >
Dec., 1948
METHYL-AND DIMETHYL1,10-PHENANTHROLINES
3995
3,7-dimethyl-1,10-phenanthroline from 4-methyl8-aminoquinoline and a-methylacrolein diacetate ; and 3-methyl-7-chloro-l,10-phenanthrolinefrom 4-chloro-8-aminoquinoline6and a-methylacrolein diacetate. I11 I1 For purposes of comparison the hitherto undescribed 2,9-&methylphenanthroline was syntheIV sized by a Skraup reaction involving 8-aminoquinCH, CH, CHI aldine and crotonaldehyde diacetate. All the ,,-- \ ,-phenanthrohes here described with the excep-+(---{, tion of the last mentioned give a positive ferroin \--x ,\---/ test. In the form of their ferrous complexes they \'I are being tested as to oxidation potential and stability by Dr. G. Frederick Smith. On the basis of preliminary tests the ferrous complexes of the folv lowing 1,lO-phenanthrolines have been found to methyl-8-nitroquinolne (IV) in considerably bet- be less than unity: 5,6-dimethyl-, 4,7-dimethyl-, ter yield than that previously d e ~ c r i b e d . On ~ re- and 3,5,6,8-tetramethyl-. The first mentioned duction IV yielded the base v, which by another derivative also possesses unusual stability. Skraup reaction was converted to 5,6-dimethyl-l,The synthesis of 3-methyl-8-nitroquinoline was 10-phenanthroline (VI). effected by a Skraup reaction involving a-methylBy treating I11 with a-methylacrolein diacetate acrolein diacetate and o-nitroaniline. For the instead of glycerol under Skraup conditions 3,5,6- preparation of 3,5,6-trimethyl-8-nitroquinolinea trimethyl-8-nitroquinoline (VII) was obtained. similar reaction was used, involving 2-nitro-4,5The amine formed by the reduction of VI1 on dimethylaniline and a-methylacrolein diacetate. treatment with glycerol under Skraup conditions The nitroquinolines were reduced to the amino yielded 3,5,6 - trimethyl - 1,lO - phenanthroline derivatives by stannous chloride. (VIII) ; on treatment with a-methylacrolein diThe 3,4-dimethylaniline used in these studies acetate i t yielded 3,5,6,8-te tramethyl-1,10-phen- was kindly supplied by Merck and Company, and anthroline (IX). the trimethoxybutane by the du Pont Company. This work was supported in part by a grant from the Committee on Research and Publications of CHI/S;' c H a c b H s Temple University. (/NO, Experimental Part XH* NO2
cHs&"H LA
)-
1
-
J VI1
Z-Nitro-4,5-dimethylaniline.-To a solution of 24 g. of 3,4-dimethylaniline in 174 ml. of concentrated sulfuric acid was added a mixture of 14 ml. of concentrated nitric acid and 44 ml. of concentrated sulfuric acid, keeping the temperature below 0". The reaction mixture was allowed to stand for one hour a t this temperature and was then poured into 3 liters of ice-water. The precipitate was filtered, dried and recrystallized from benzene. Fourteen grams of 2-nitro-4.5-dimethvlaniline was thus obtained. m. D. 137VI11 1); 138"; yield, 42.6%. Preparation of the 8-Nitroquinolines.-A mixture of one I n the preparation of methyl- and dimethyl1,lO-phenanthrolines with the methyl groups in molar-proportion of the appropriate nitroaniline, 0.6 mole arsenic pentoxide, 4 moles of sulfuric acid in 96.8% soluthe nitrogen rings, the general procedure was to of tion and a volume of water equal to one-third of the volume use a Skraup reaction on the appropriate amino- of sulfuric acid used was heated to 100" and treated with quinoline using as the other component either glycerol (3.5 moles) or a-methylacrolein diacetate (1.8 glycerol, a-methylacrolein diacetate or 1,3,3-tri- moles) at such a rate that the temperature did not exceed 140". This temperature was maintained for two hours, methoxybutane. The sulfuric acid used was first after which the mixture was poured into water, neutralized diluted as suggested by U n t e r m ~ h l e n ,and ~ the with sodium hydroxide, and the precipitate extracted with water gradually evaporated. Arsenic acid was hot benzene. The residue was then crystallized from benzene, except in the case of 3-methyl-S-nitroquinoline, where used throughout as the oxidizing agent. benzene-petroleum ether was used. The results are shown In this way 4-methyl-1,lO-phenanthrolinewas in Table I. prepared from 4-methyl-8-aminoquinoline and General Procedure for the Synthesis of 1,lO-Phenanglycerol; 3-methyl-l,l0-phenanthrolinefrom 8- thro1ines.-A mixture of one molar proportion of the apaminoquinoline and a-methylacrolein diacetate ; propriate aminoquinoline, 0.65 mole of arsenic pentoxide, moles of sulfuric acid in 96.8% solution, and a volume of 3,8-dimethyl-l,10-phenanthroline from 3-methyl- 4water equal to one-third of the volume of sulfuric acid used 8-aminoquinoline and a-methylacrolein diacetate ; was heated to 100" and treated with glycerol (3.6 moles), 4,7-dimethyl-l,10-phenanthroline from 4-methyl- u-methylacrolein diacetate (1.8 moles), 1,3,3-trimethoxy8-aminoquinoline and 1,3,3-trimethoxybutane; butane (1.3 moles), or crotonaldehyde diacetate (1.6 moles) at such a rate that the temperature did not exceed 111
Rase
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(4) Manske, Can. 1.Research, SOB, 133 (1942). ( 5 ) lintcrmohlen. T Ora C h r v , 8. 544 ( 1 9 4 3
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(6) Riegel and co-workers. THISJOURNAL. 68. 1633 (194fi)
FRANCIS H. CASE
3996
Vol. 70
TABLEI NITROQUXNOLINES In Tables I and 11, G = glycerol; MAD = a-methylacrolein diacetate; TMB = 1,3,3-trimethoxybutane; CAD = crotonaldehyde diacetate. Quinolines 3-Methyl-&nitro3,5,6-Trimethyl-8-nitro5,6-Dimethyl-8-nitroo-Nitro Z-Nitro-4,5-dimethyl2-Nitro-4,5-dimethylFirst, -aniline Component MAD MAD G Second M. p., "C. 110-111 224-225 163-164 42.9 65.5 63.5 Yield, % Previ66.65 Calcd. 63.82 ously 66.52 Found 63.81 Analyses, Carbon pre% Hydrogen Calcd. 4.29 5.59 pared4 Found 4.28 5.51
1
[
TABLEI1 1,10-PHENANTHROLINES 1,lO-Phenanthroline
a
3-Methyl 4-Methyl 3,s-Dimethyl 4,7-Dimethyl 3,7-Dimethyl 5,fj-Dimethyl 2,!3-Dimethyla 3,3,6-Trimethyl 3,5,6,8-Tetramethyl 3-Methyl-7-chloro The analysis is for the
1st Component S-aminoquinoline-
2nd Component
OC.
Yield,
%
Analyses, % Carbon Hydrogen Calcd. Found Calcd. Found
MAD G MAD TMB MAD
158-159 6.1 80.39 80.52 4-Methyl144-145 14.9 80.39 79.99 3-Methyl212 8.8 80.74 80.95 4-Methyl194-195 7.0 80.74 80.76 4-Methyl136-137 2.3 80.74 81.23 5,6-DimethylG 265-266 9.3 80.74 80.43 2-MethylCAD 159-160 7.6 77.39 77.43 5,6-DimethylMAD 196-197 9.3 81.05 80.97 3,5,6-TrimethylMAD 260-261 22.2 81.32 81.55 4-ChloroMAD 178-179 3.5 68.27 68.02 hemihydrate, obtained on crystallization froin water; HzO calcd. 4.15,
140'. Heating was continued a t this temperature for three hours. The mixture was then poured into water, made alkaline, and the tarry precipitate filtered off. The filtrate was extracted three times with benzene, which was then used to extract the phenanthroline from the solid material. After removal of the benzene the phenanthroline was crvstallized from benzene. The results are shown in Table iI. 3-Methyl-S-aminoquinoline.--Reduction of 3-methyl-8nitroquinoline was effected by refluxing 500 ml. of an alcoholic solution containing 24 g. of nitro compound and 87 g. of SnC12.2fIzO for three hours. After removal of the alcohol the residue was made alkaline and extracted with ether. The crude base obtained by removal of the ether was distilled in vacuo; yield, 16 g., b. p. 156-164' (13 mm.). A sayple, crystallized from petroleum ether, melted a t 7071 Anal. Calcd. for CloHloNz: C, 75.92; H, 6.37. Found: C, 76.11; H , 6.46.
.
M. p.,
5.19 5.31 5.19 5.39 5.81 5.63 5.81 5.91 5.81 5.91 5.81 5.84 6.03 6.16 6.33 6.34 6.83 6.70 3.97 3.94 found 3.87%.
3,5,6-Trimethyl-8-aminoquinoline.-This was obtained by the reduction of 45 g. of nitro compound with 141.5 g. of SnCl2.2H*0in 900 ml. of alcohol; yield, 26 g., m. p. 939 4 O , when crystallized from petroleum ether. Anal. Calcd, for c 1 2 ~ l ,c, ~ z77.38; : H, 7.58. Found: c, 77.24; H, 7.44.
Summary The syntheses of the following 1,lO-phenanthrolines are described: 3- and 4-methyl, 33-, 4,7-, 3,7-, 2,9- and 5,6-dimethyl, 3,5,6-trimethyl, 3,5,6,8-tetrame thyl, 3-methyl-7-chloro-. The syntheses of 3-methyl- and 3,5,6-trimethyl84troquinoline and the corresponding amino derivatives are described. RECEIVED JULY 2, 1948
