ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 3, pp. 459–460. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © A.O. Chunaev, E.A. Stepanov, P.P. Purygin, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 3, pp. 463–464.
SHORT
COMMUNICATIONS
Reaction of N,N-Dimethylaniline with N-Cyanoazoles
according to Electrophilic Aromatic Substitution Pattern
A. O. Chunaev, E. A. Stepanov, and P. P. Purygin
Samara State University, ul. Akademika Pavlova 1, Samara, 443011 Russia
e-mail: zver_nauki@mail.ru
Received May 25, 2009
DOI: 10.1134/S1070428010030309
N-Cyanoazoles are highly reactive organic com-
pounds and important intermediate products in the
synthesis of numerous derivatives containing an azole
ring. Owing to high polarity of the cyano group,
N-cyanoazoles are capable of acting as electrophilic re-
agents in electrophilic aromatic substitution reactions.
In the present communication we report on the syn-
thesis of some imines via electrophilic aromatic sub-
stitution of hydrogen in N,N-dimethylaniline by N-cy-
anoimidazole, N-cyanobenzimidazole, N-cyano-1,2,3-
benzotriazole, and N-cyano-2-methylimidazoles. Initial
N-cyanoazoles Ia–Id were prepared according to
standard procedures. We were the first to demonstrate
that the above listed N-cyanoazoles react with N,N-di-
methylaniline in the presence of anhydrous aluminum
bromide to give para-substituted imines in good yields
(65–74%). Azole-containing imines IIa–IId were char-
acterized by sharp melting points and Rf values, and
their structure was confirmed by elemental analyses
and 1H NMR spectra.
N,N-Dimethyl-4-[azolyl(imino)methyl]anilines
IIa–IId (general procedure). Anhydrous aluminum
bromide, 4 g, was dissolved in 50 ml of anhydrous
nitrobenzene on cooling in an ice–salt bath, and a solu-
tion of 15 mmol of N-cyanoazole Ia–Id in 20 ml of
anhydrous nitrobenzene was slowly added dropwise
under stirring at 6°C. The mixture turned yellow–
orange. It was stirred for 1 h, and a solution of 1.9 ml
(1.82 g, 15 mmol) of N,N-dimethylaniline in 15 ml of
anhydrous nitrobenzene was added. The mixture
turned red or blue and was stirred for 4 h, the solvent
was distilled off under reduced pressure (3 mm), and
the tarry residue was extracted with anhydrous chloro-
form. The solvent was distilled from the extract on
a rotary evaporator under reduced pressure (water-jet
pump) at a bath temperature not exceeding 40°C. The
crystalline product was stored in a vacuum desiccator
over calcium chloride.
4-[1H-Imidazol-1-yl(imino)methyl]-N,N-dimeth-
ylaniline (IIa). Yield 2.12 g (66%), mp 186°C (from
1
benzene), Rf 0.56. H NMR spectrum, δ, ppm: 3.2 br.s
Nitrobenzene was found to be appropriate solvent
for carrying out reactions of N-cyanoazoles Ia–Id with
N,N-dimethylaniline. High polarity and dissolving
power of nitrobenzene ensure homogeneity of the re-
action mixture throughout the process. On the other
hand, nitrobenzene itself is not involved in the reaction
because of the presence of a strong electron-withdraw-
ing nitro group in its molecule.
(6H, NMe2), 5.9 s (1H, NH), 7.2 d (2H, o-H), 7.5 m
(2H, 4-H, 5-H), 7.8 m (2H, m-H), 8.1 br.s (1H, 2-H).
Found, %: C 67.38; H 6.48; N 26.14. C12H14N4. Cal-
culated, %: C 67.29; H 6.54; N 26.17.
4-[Imino(2-methyl-1H-imidazol-1-yl)methyl]-
N,N-dimethylaniline (IIb). Yield 2.22 g (65%),
mp 168°C (from benzene), Rf 0.65. 1H NMR spectrum,
δ, ppm: 2.5 s (3H, 2-CH3), 3.2 br.s (6H, NMe2), 6.2 s
(1H, NH), 7.2 d (2H, o-H), 7.5 m (2H, 4-H, 5-H), 7.6–
7.7 m (2H, m-H). Found, %: C 68.53; H 6.97; N 24.50.
C13H16N4. Calculated, %: C 68.42; H 7.02; N 24.56.
NH
NMe2
Ht
AlBr3
+
Ht CN
Me2N
4-[1H-Benzimidazol-1-yl(imino)methyl]-N,N-di-
methylaniline (IIc). Yield 2.12 g (74%), mp 205°C
Ia–Id
IIa–IId
1
(from benzene), Rf 0.73. H NMR spectrum, δ, ppm:
Ht = 1H-imidazol-1-yl (a), 2-methyl-1H-imidazol-1-yl (b),
1H-benzimidazol-1-yl (c), 1H-1,2,3-benzotriazol-1-yl (d).
3.2 br.s (6H, NMe2), 5.9 s (1H, NH), 7.2 d (2H, o-H),
459
Chunaev
