Cyclooligomerization of acetylene with acetonitrile to 2-amino-3-(1- iminoethyl)-6-methylpyridine in the system KOH-CH3CN

Full text of DOI:10.1023/B:RUJO.0000010229.95022.bd

Russian Journal of Organic Chemistry, Vol. 39, No. 9, 2003, pp. 1358 1359. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 9, 2003,
pp. 1430 1431.
Original Russian Text Copyright
2003 by Trofimov, Mal’kina, Afonin, Ushakov, Nosyreva, Bel’skii.
SHORT
COMMUNICATIONS
Cyclooligomerization of Acetylene
with Acetonitrile to 2-Amino-3-(1-iminoethyl)-6-methylpyridine
in the System KOH CH3CN
B. A. Trofimov, A. G. Mal’kina, A. V. Afonin, I. A. Ushakov,
V. V. Nosyreva, and V. K. Bel’skii
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
Received March 27, 2003
Cyclooligomerizations of acetylene to benzene,
cyclooctatetraene, and higher cyclic polyenes in the
presence of transition metal salts or complexes have
been well documented [1, 2]. Analogous but less
explored from the preparative viewpoint reactions
occur in systems consisting of a strong base and polar
aprotic solvent (superbasic medium) in the presence
of alkali metal cations [3 6].
Gairns et al. [7] reported on the cyclization of
acetylene with two molecules of acetonitrile to afford
2,4-dimethylpyrimidine (yield 8%) in the presence of
potassium under pressure and at elevated temperature
(16 17 atm, 175 200 C, 7 h). In the present com-
munication we briefly describe a new cyclooligo-
merization of acetylene with acetonitrile, which occurs
under mild conditions ( 15 to 20 C, atmospheric
pressure, KOH MeCN) and leads to formation of
2-amino-3-(1-iminoethyl)-6-methylpyridine (I) in one
preparative step (Scheme 1). Compound I is the
product of condensation of one acetylene molecule
with three molecules of acetonitrile.
with one or several acetylene molecules [6, 8, 9],
gives rise to a complex with acetonitrile and acts as
a coordinating center (template).
2-Amino-3-(1-iminoethyl)-6-methylpyridine (I).
Acetonitrile, 7.83 g (190 mmol) was saturated with
acetylene at 18 20 C over a period of 15 min. The
solution was cooled to 15 C, 0.66 g (11.8 mmol) of
finely powdered potassium hydroxide (preliminarily
calcined for 5 h at 450 500 C) was added, and
acetylene was bubbled through the mixture for 2 h
at 15 C. The mixture was allowed to warm up to
18 20 C, while continuously bubbling acetylene
(6 h), and the resulting dark brown mixture was left
overnight. The solid precipitate, 1.4 g, was filtered off
and washed with 10 g of diethyl ether. The washings
were combined with the filtrate, 3.04 g, which con-
sisted mainly of acetonitrile, dried over MgSO4, and
evaporated under reduced pressure. The dark residue
(0.24 g) was treated with 10 ml of boiling hexane to
isolate 0.01 g of light yellow needles with mp 133
1
134 C. IR spectrum (KBr), , cm : 3420, 3300, 3139
(C H, pyridine), 2923, 2855 (C H, CH3), 1612,
1589 sh, 1549 (pyridine), 1464, 1440, 1388, 1374,
1284, 1248, 1231, 1196, 1164, 1087, 1051, 1036,
979, 932, 863, 795, 770, 698, 588, 574, 553, 523.
1H NMR spectrum, , ppm: 9.32 br.s (1H, NH),
Scheme 1.
3
7.55 d (1H, 4-H, J4, 5 = 8.1 Hz), 7.35 br.s (2H,
3
NH2), 6.38 d (1H, 5-H, J4, 5 = 8.1 Hz), 2.39 s (3H,
CH3C N), 2.37 s (3H, 6-CH3). 13C NMR spectrum,
C, ppm: 174.26 (C NH), 159.94 (C6), 158.26 (C2),
138.86 (C4), 111.50 (C5), 110.98 (C3), 28.22
(CH3C N), 24.42 (6-CH3). Mass spectrum, m/z
(Irel, %): 149 (100), 148 (20), 132 (63), 109 (23), 108
(29), 42 (13), 28 (14). Found, %: C 63.73; H 7.77;
Presumably, intermediate dimeric ambident anion
A adds to acetylene molecule to give carbanion C
which then gives rise to pyridine ring via addition
of the third acetonitrile molecule (Scheme 2). Here,
potassium cation, which is known to form complexes
1070-4280/03/3909-1358$25.00 2003 MAIK Nauka/Interperiodica

CYCLOOLIGOMERIZATION OF ACETYLENE WITH ACETONITRILE
1359
Scheme 2.
N 27.63. C8H11N3. Calculated, %: C 64.40; H 7.43;
N 28.16.
REFERENCES
1
The H and 13C NMR spectra were recorded on
1. Reppe, W., Neue Entwicklungen auf dem Gebiet der
Chemie des Acetylens and Kohlenoxids, Berlin:
Springer, 1949.
2. Copenhaver, J.V. and Bigelow, M.H., Acetylene and
Carbon Monoxide Chemistry, New York: Reinhold,
1949.
a Bruker DPX 250 spectrometer (250.1 and 62.9 MHz,
respectively) from 0.1 or 5 10 wt % solutions in
CDCl3 using HMDS as internal reference. The IR
spectra were measured on Specord 75IR and Bruker
IFS-25 spectrometers. The mass spectra were obtained
on a Finnigan GCQ instrument with direct sample
admission into the ion source. Commercial aceto-
nitrile was distilled over P2O5. The structure of
2-amino-3-(1-iminoethyl)-6-methylpyridine (I) was
also proved by X-ray analysis (the results will be
reported in a separate communication).
3. Trofimov, B.A., Zh. Org. Khim., 1986, vol. 22,
p. 1991.
4. Trofimov, B.A., Z. Chem., 1986, vol. 26, no. 2, p. 41.
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p. 1233.
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no. 13, p. 1121.
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Chem. Soc., 1952, vol. 74, no. 16, p. 3989.
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shtein, V.G., and Trofimov, B.A., Izv. Akad. Nauk
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Despite the poor yield (which, however, may be
increased by optimizing the reaction conditions), the
above one-pot chemo- and regioselective synthesis of
pyridine derivative I possessing a rare combination
of functional groups may be of practical importance
provided that such building block would be needed.
The procedure is based on readily accessible initial
reactants and is very simple, and any amount of the
product can be prepared.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 9 2003