Cyanocarbon Chemistry. VI.1 Tricyanovinylamines

---

2806

B.

c. A~CKWSICK, R.E. HECKERT, T. L. CAIRNS, D. D. COFFMAN A N D H. F.A l O W E R

solution of the acid in water, and barium 2-bromo-1,1,3,3tetracyanopropenide precipitated. Tetraethylammonium 2-Chloro-l , 1,3,3-tetracyanopropenide.-A solution of 6.9 g. (0.1 mole) of sodium nitrite in 25 ml. of water was added dropwise with stirring to a solution of 14.2 g. (0.05 mole) of tetraethylammonium 2-amino-l,1,3,3-tetracyanopropeiiide in 500 ml. of water and 25 nil. of hydrochloric acid. The resulting solution was heated t o boiling, treated with carbon-black, and filtered. The precipitate that formed when the filtrate was cooled was collected on a filter, washed with water and dried (10.2 9.). This material was recrystallized from water to give 6.3 g. of orange needles of tetraethylammonium 2-chloro-1 ,I,3,3tetracyanopropenide. N-Methylquinolinium 2-chloro-l , 1,3,3-tetracyanopropenide was prepared by a similar procedure from N-methylquinolinium 2-amino-l , 1,3,3-tetracyanopropenide. Tetramethylammonium 2-Chloro-l , 1,3,3-tetracyanopropenide.-A solution of 5.0 g. of N-methslquinolinium 2amino-1,1,3,3-tetracyanopropenidein 50 ml. of hot water was passed through an acidic ion-exchange column (Amberlite IR-120-H). Concentrated hydrochloric acid, 10 ml., and then a solution of 5.0 g. of sodium nitrite in 25 ml. of water was added t o the cooled percolate. The resulting solution was boiled for 5 minutes, cooled and then mixed with 10 ml. of aqueous 30y0 tetramethylammonium chloride solution. The precipitate that formed was collected on a filter, washed with water, and recrystallized from water. There was obtained 1.2 g. of tetramethylarninoiiium 2chloro-l,l,3,3-tetracyanopropenideas long colorless needles, m.p. 211-213’. Barium Tricyan0methanide.-A hot aqueous solution (50 ml.) of barium chloride dihydrate was added. with stirring to a hot solution of 33.9 g. of sodium tricyanomethanide in 50 ml. of \+ater. The resulting solution was stored in a cold room a t 4’ for one week. The large crystals that formed were collected on a filter and recrystallized from water. There

[CONTRIBUTION NO. 440

FROM TIIE

was obtained 17.5 g. of barium tricyanomethanide as colorless crystals, m.p. >300°. Anal. Calcd. for BaCBX6: C , 30.26; N, 26.47. Found: C, 29.80; N, 26.30. l-Amino-l-chloro-2,2-dicyanoethylene.17-Dryhydrogen chloride was passed into a solution of 6.4 g. of potassium tricyanomethanide in 200 ml. of acetone for 10 minutes. The precipitate of potassium chloride (3.5 9.) was separated by filtration, and the filtrate was allowed to stand a t solid carbon dioxide temperature overnight and was then poured into n-heptane. The oil that separated was extracted with ethyl ether. On evaporation, the ether extract yielded 4 g. (63y0 yield) of l-amino-l-chloro-2,2-dicyanoethyleneas a light yellow solid. Anal. Calcd. for C4H2C1S3: C, 37.67; H , 1.57; C1, 27.80; N, 32.95. Found: C, 37.99; H, 1.73; C1, 27.46; N, 32.89. l-Amino-2-bromo-2,2-dicyanoethylenewas obtained as a sublimable white solid in a similar manner by the reaction of dry hydrogen bromide with potassium tricyanomethanide. Anal. Calcd. for C4HzBrN3: hT,24.43. Found: N, 24.82. l-Xmirio-2-bromo-2,2-dicyanoethylene reacted a t 20-30’ with ethyl alcohol t o form l-amino-l-ethoxy-2,2-dicyanoethylene (m.p. 218-219’) and with methyl alcohol to yield l-amino-l-methoxy-2,2-dicyanoethylene ( m .p. 213-2 14’). Ultraviolet Spectra.-The ultraviolet absorption spectra of a number of free cyanocarbon acids and their salts were determined. The absorption maxima and extinction coeficients for a given free acid and any of its salts were essentially identical, so only the anions are listed in Table 11. (17) E. L. Little, E. S. Patent 2,773.892 (1956).

WILMINGTON, DELAWARE

CENTRAL RESEARCH DEPARTMEST, EXPERIMENTAL STATION, E. I. A N D CO.]

Cyanocarbon Chemistry. VI. BY B.

\’d.80

DU

POST DE NEMOLTRS

Tricyanovinylamines

c. MCKUSICK,R. E. HECKERT, T. L. CAIRNS,D. D. COFFMAN AND H. F. MOWER RECEIVED NOVEMBER 14, 1957

Tetracyanoethylene reacts with primary amines and some secondary amines t o give hT-tricyaiiovinylaiiiiiies (I). I t generally reacts with secondary and tertiary arylamines by attacking the aromatic ring t o give 4-tricyanovinylarylamines such as 11. The 4-tricyanovinylarylarnines are a new class of dyes with strong affinity for hydrophobic fibers. Some of their analogs have similar dyeing characteristics.

Tetracyanoethylene reacts with ammonia and hydrazine with elimination of hydrogen cyanide to give, respectively, bis-(tricyanoviny1)-amine and 1,2-bi~-(tricyanovinyl)-hydrazine.~The present paper describes the related reactions of tetracyanoethylene with amines. N-Tricyanoviny1amines.-Tetrac y anoethylene reacts readily with primary or secondary aliphatic amines and with most primary and some secondary aromatic amines to give N-tricyanovinylamines (I) and hydrogen cyanide. RR’NH

+ C(CN)Z=C(CN)i

+

RR’NC(CN)=C(CN),

+ HCN

I

Sixteen such N-tricyanovinylamines, all solids ranging in color from white to yellow, have been prepared (Table I). The N-tricyanovinylamine structure is assigned partly on the basis of absorption spectra. Thus, N-tricyanovinyl derivatives V.

(1) Paper V, W. J. Middleton, E, L. Little. D. D. Coffmao and A. Engelhardt. T H IJOURNAL, ~ 80, 2795 (1958).

of primary amines (e.g., aniline, rz-butylamine) absorb strongly in the N-H stretching region of the infrared, whereas N-tricyanovinyl derivatives of secondary amines (e.g., N-methyl-p-toluidine, piperidine) do not. The compounds are hydrolyzed by base to give the parent amine in good yield, which is evidence that the tricyanovinyl group is attached to nitrogen rather than carbon. Acid hydrolysis of N-tricyanovinyl-n-butylamine gave a-n-butylamino-P-cyanomaleimide. RR’NCC=O >NH NC-CC=O

I/

Hz0 yc~ RR’KC( C N )=C( CN)n

I

1

L -

H20 XaOH

RR’NH

N-Tricyanovinylamines can react with a second molecule of amine t o give 1,l-diamino-2,2-dicyanoethylenes. B U N H C ( C N ) - C ( C ~ ’ ) ~4- MezNI-I --+ BuNHC! KLIcL)- C( CN)I

TRICYANOVINYLAMINES

June 5 , 1958

4-Tricyanovinylarylamines.-Tetracyanoethylene does not react with tertiary aliphatic amines like triethylamine, but i t readily reacts with both tertiary and secondary aromatic amines, attacking the ring to give 4-tricyanovinylarylamines. For example, N,N-dimethylaniline gives 4-tricyanovinyl-N,N-dimethylaniline (11). 2 ( C H Z ) & ~ - C (CN)=C( CN),

I1

2807

I and 11) indicate that o-tricyanovinylation of arylamines cannot easily occur, that one N-substituent generally prevents N-tricyanovinylation unless the para position is filled, and that substituents ortho to the amine group promote p-tricyanovinylation a t the expense of N-tricyanovinylation. 1,3,3-Trimethy1-2-methyleneindoline and 1,lbis-(4-dimethylaminophenyl)-ethylenereacted with tetracyanoethylene to give the tricyanovinyl derivatives VI and VII, respectively. Evidently some vinylamines and p-aminoarylethylenes can react with tetracyanoethylene in the same manner as arylamines.

The 4-tricyanovinylarylamines absorb visible light very strongly (emsx 37,000-47,OOO) and comprise a new class of brilliant red and blue dyes that often have great affinity for hydrophobic fibers. The strong absorption of visible light is consistent with the highly conjugated structure assigned, and infrared spectra confirm the structure; thus, the product from tetracyanoethylene and N-methylaniline, 4-tricyanovinyl-N-methylaniline,absorbs V\N/ strongly in the N-H stretching region of the inI frared. Chemical evidence for the 4-tricyanoVI CHI vinylarylamine structure was supplied by stepwise (4-Me2NCeH&C=CHC( CN)=C( CN)? hydrolysis of 4-tricyanovinyl-N,N-dimethylaniline VI1 (11) to ethyl 4-dimethylaminobenzoate via 4-(1A few derivatives of the 4-tricyanovinylarylhydroxy - 2,2 - dicyanovinyl) - N,N - dimethylaniline amines have been prepared (Table 11). 4-Tri(111). cyanovinyl-N, N-dimethylaniline (II) reacts with NaOH EtOH nitric acid under mild conditions to give a monoI1 ~-M~&HCE.H~(~)=C(CN)~ HC1 nitro derivative in which the nitro group is probI11 4-Me*NCa&OzEt ably ortho to the amino group. 4-TricyanovinylThe intermediate vinyl alcohol I11 is a strong aniline has been N-acylated, and both i t and 4acid (PITa 2.3) ; i t is formulated as a zwitterion on tricyanovinyl-2,6-dimethylaniline have been diazothe basis of its infrared spectrum. Three other 4- tized and coupled to give azo compounds. tricyanovinylanilines were similarly converted to Dyeing Properties of 4-Tricyanovinylarylamines. vinyl alcohols by mild alkaline hydrolysis. The -Many of the 4-tricyanovinylarylamines give vinyl alcohols are assigned a 1-hydroxyvinyl rather brilliant dyeings, most often red, on hydrophobic than a 2-hydroxyvinyl structure because i t has fibers such as polyethylene terephthalate and been shown in the analogous reaction of tricyano- polyacrylonitrile. The dyeings have good washvinylbenzene with alkoxide ion that l-alkoxy-2,2- fastness. Over fifty 4-tricyanovinylarylamines dicyanovinylbenzene is formed.3 (Table 11) have been prepared. All things conThe structure of 4-tricyanovinyl-N,N-dimethyl-sidered, 4-tricyanovinyl-N-methyl-N-(2-benzoxyaniline (11) was established definitely by an un- ethyl)-aniline (VIII) is the best of these dyes yet equivocal synthesis. Hydrogen cyanide was added 4-CsHsC02CHzCH2N(CHs)C&C( CN)=C( CN)2 to 4-dimethylaminobenzalmalononitrile (IV), and VI11 the adduct V was oxidized to 4-tricyanovinyl-N,Nprepared. Its wash-fastness, sublimation-fastness, dimethylaniline (11) by lead tetraacetate. Several other 4-tricyanovinylarylamines were made in the light-fastness and affinity for hydrophobic fibers are all good. It can be applied from a moderately same way. acidic bath (pH 3-6) without serious decomposition, 1, NaCN but, like other simple tricyanovinylarylamine dyes, 4-Me2r\lTC6H4CH=C(CN)z+ Tv 2, HOAc i t is rapidly decomposed in basic dye baths. The decomposition by base involves replacement of the Pb( 0Ac)c ~ - M ~ z N C ~ H I CN)CH( CH( CN)2 ___i) I1 a-cyano group by hydroxyl, as in the conversion of V I1 to 111. The bulkiness of the tricyanovinyl group makes Analogs of 4Tricyanovinylarylamines.-A numsteric factors of great importance in determining ber of analogs of tricyanovinylarylamines (Table the course of reaction of an arylamine with tetra- 11) were prepared in efforts to get dyes of other cyanoethylene. Thus, with aniline or N-methyl- shades and better properties. One analog (IX) fi-toluidine only an N-tricyanovinyl derivative was had a carbethoxy group instead of a cyano group in isolated ; with N-methylaniline only a p-tricyano- the a-position of the vinyl group; i t was prepared vinyl derivative was isolated; with 2,6-dimethyl- by condensation of ethyl 4-dimethylaminoglyoxyaniline both an N-tricyanovinyl derivative and a late with malononitrile. The other analogs (X) p-tricyanovinyl derivative were formed ; and with had a chromophore other than cyano a t the pN,N-dimethyl-$-toluidine no tricyanovinylation a t position of the vinyl group. all was detected. These and other results (Tables

-

-

(2) This reaction is the basis of a semi-quantitative determination of tetracyanoethylene. (3) Paper VII, G. N. Sausen, V. A. Engelhardt and B. S. Fisher, TEISJOURNAL, 80, 2815 (1958).

4-Me2NCsHX( COzEt)=C( CN)Z IX ~-R,NC&IH,C(CN)=C(C?J)Z(Z= COAr, CO?R, etc.)

s

PROPERTIES O F

TABLE I N-'rRICYAXOVIXYLAMINES, RR'xC( cN)-c(cN EtOH

Yield, X-Tricyanuvinylamine rt-CaHeNHCz(CN)s (CHdbNCz(CN)3 CYC~O-C~HIINHCZ(CN)~ >~-CI~H~,SHC~(CN)~ CsHsCHzXHCz(CS)a CoHsNHCz(CNj3 o-CHaCsHaNHCz(CS)i' P-CHSC~HINHCZ(CN)~ P-C HaCsHaN (CHa)Cz(C N) 3 P-ClCaHaKHCz(CX)3 7)t-OzNCsHi(NHC?(CN) 3 ,h-O2NC6HnNHCg(CX)3 O-HOCOHINHCP(CN)~ p-CHsOCOCsHaSHCr(CS)3 P-C~H~[NHC~(CN)~]Z ~-C~OHI?;HCZ(CX)~

r6

07 37 51 41 07 ;10 23

49 80 84 5;

-IC Dl 53

78 45

M.p,v

oc.

58 86-87 147-148 83 121-122 176 129-130 174 174- 17ti 160 171 170 >300 180 >300 179

Crystn. solvent BtzO/petr.ether CsHs/petr.ether CHCls/CClr HOAc/HzO CHCl3/CClc Benzene 50% HOAc HOAc/H20 Et OH 80% E t O H 50% MeOH 50% E t O H Acetoneb EtOH Acetone HOAc/HzO

,,.,A

mp

325 334 325 320 327 345 330 350 335 34G 345 332 341 360 375 330

emsx

X 10-2 127 154 136 123 141 147 119 135 110 149 159 155 195 172 223 106

)$

Carbon, yo Hydrogen. '.& Nitrogen, b,' Formula Calcd. Found Calcd. Pound Calcd. F o u n d 32.2 32.3 5.9 62.1 5.8 CeHlaXa 02.0 29.6 5.4 30.1 64.5 2.4 C~oHioXi( 64.5 28.0 28.3 6.0 6.2 G6.0 66.1 CiiHizNa 15.1 15.0 10.3 10.0 73.7 C Z ~ H ~ B K ;7~4 . 5 26.9 "6.8 3.9 69.2 3.9 CnHsiXa 09.2 28.9 28.5 3.2 68.3 3.1 CnHsNaC 68.0 26.9 27.0 3.9 4.1 09.6 CizHsNa 69.2 26.9 27.0 4.0 3.9 69.3 CnHsNa 69.2 Ci3Hloriild 70.3 70.2 4.5 4.6 25.2 22.1 2.2 2.2 24.5 24.3 57.8 CiiHsNaCl 57.8 2.1 2.3 29 3 29.0 55.4 CiiHsNsOz 55.2 2.1 2.1 29.3 29.0 55.4 CiiHsNaOn 55.2 2.9 3.0 63.0 CiiH~Na0 02.8 3.2 3.5 22.2 22.5 01.9 61.8 Ci3HsS40z 2.0 2.0 36.2 36.3 61.9 62.1 Ci6HsiK;1 3.3 3.5 42.0 43.4 73.8 73.8 CisHsNa

Calcd. : a Co:itamin:tted tvith 7% 4-tricyanovinyl-o-toluditie. * No good solvent found ; purification by slurrying. mol. wt., 194. Found: mol. wt. (in boiling acetone), 198. Calcd.: mol. wt., 222. Found: mol. wt. (in boiling acctoiie), 217.

The latter analogs (X) were prepared as in the ethylene iii 200 1111. of tetrahydrofuran held a t 200-30'. The mixture was stirred arid refluxed for three hours. Disconversion of I V to 11, by condensing a 4-amino- tillation of solvent a t a pressure of 30 xnm. (bath teniperabenzaldehyde with a compound having an active ture 40') left a crystalline residue. This 011 crystallization inethylene group, adding hydrogen cyanide to the ethanol gave 30.0 g. (My0yield) of p-chloro-Nnylaniliiie in the forni of yellow crystals, m.p. product, and oxidizing. The same method was used to prepare 4-(4-dimethylaminophenyl)-1,3- 160'. Dimcthylformamide was used as a reaction medium in butadiene-1,1,2-tricarbonitrile (XI), a deep blue place of tetrahydrofuran with similar results. Conditions dye vinylogous to the 4-tricyanovinylarylamines. were as described later in this paper for the synthesis of 4Its structure was established by two-step hydrol- tricyanovinylarylamines from arylamines and tetracyanobut with equivalent quantities of reactants. ysis to methyl 4-dimethylaminocinnamate. The ethylene, Hydrolysis of N-Tricyanovinylaniline to Aniline.-A blue color of an alcohol solution of the trinitrile XI mixture of 1.00 g. of N-tricyanovinylaniline and 50 ml. of is instantly destroyed by base, but acid regenerates 10% potassium hydroxide was refluxed for three hours and it, and the ability of the basic solution to give back steam distilled. The distillate, which contained oily drops, was extracted with ether. The dried extract was saturated color on acidification is only gradually lost over a with hydrogen chloride to precipitate Od44 g. (66% yield) period of hours. These observations suggest that of aniline hydrochloride, m.p. 194-196 . The hydrochlobase reversibly converts X I t o the colorless inter- ride was treated with 5 ml. of 20y0 sodium hydroxide, and mediate XI1 which gradually and irreversibly the liberated aniline was taken up in ether. Addition of 1 of pyridine and 0.5 ml. of acetyl chloride to the dried breaks down to XIII. Intermediates like XI1 are ml. ether solution gave acetanilide, m.p. 113-114' alone or probably formed during the far faster basic hydroly- mixed with an authentic sample. sis of the 4tricyanovinylarylamines. Similarly, 2.00 g. of I\'-methyl-I'-tricyaiiovinyl-il-tolui-

4-h.le~XC~I&CH=C€-IC(CN)( OH)C-( CN), + SI1 4-hIe,~CBI-r,CH-CHC(OH)=C( CN)z 4-CNXI11

'The analogs of 4-tricyanovinylarylamines share +heirvirtues and defects as dyes. None was prepared that was the equal of the best 4-tricyano\-inylarylamines in dyeing properties. Acknowledgments.. --\.?'e are indebted to Drs. I). R. Raer, S. 3.Boyd and 11. P. Lander1 of the Organic Cheiiiicals Department, E. I. du Pont dc n'eiiiours & Co., for supplyitig iiiterriiedintes and giving valuable advice. Experimental N-Tricyan~vinylamines~(Table I).--'Yhe S-tricyauovinylarnines generally were made by the interaction of tetracyanoethylene with primary or secondary amines in boiling tetrahl-drofuraii. So more than a slight excess of amine was used to avoid formation of 1,l-diamin0-2,2-dicyanoctliylencs. In a typical experiment, 20.0 g. (0.157 mole) of p-chloronniline was added nver a period of about 20 rninutcs a stirred snlutiori o f 20.0 g . (0.156 mole) of tetracyallo_ _ .. __ 1 4 ) I