Reactivity of 4-methylpyridinium salts in a new reaction of ring transformation of pyridine and isoquinoline derivatives

Article abstract of DOI:10.1007/s11178-006-0018-8

Dependence of reactivity on substituents in the pyridine ring of the 4-methylpyridinium salts was studied in intermolecular reaction of ring transformation involving quaternary salts of pyridinium and isoquinolinium promoted by methylammonium sulfite.

Full text of DOI:10.1007/s11178-006-0018-8

Russian Journal of Organic Chemistry, Vol. 41, No. 11, 2005, pp. 1678-1682. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 11, 2005,
pp. 1712-1716.
Original Russian Text Copyright Ó 2005 by Gromov, Fomina, Grishina, Kurchavov.
.
Reactivity of 4-Methylpyridinium Salts in a New Reaction of Ring
Transformation of Pyridine and Isoquinoline Derivatives
S.P. Gromov, M.V. Fomina, Yu.B. Grishina, and N.A. Kurchavov
Photochemistry Center of the Russian Academy of Sciences, Moscow, 119421 Russia
e mail: gromov@photonics.ru
Received October 4, 2004
Abstract—Dependence of reactivity on substituents in the pyridine ring of the 4-methylpyridinium salts was
studied in intermolecular reaction of ring transformation involving quaternary salts of pyridinium and isoquinolinium
promoted by methylammonium sulfite.
The capability of azines and their quaternary salts to
suffer ring transformation under the action of nucleophilic
agents is well known. These processes are characteristic
of electron-deficient heterocycles with two or more nitro-
gen atoms, and of their fused analogs [1].
Isoquinoline derivatives may be regarded both as
a fused azine system which is characterized as a whole
by a higher electron-deficiency with respect to nucleo–
philes [1, 9], and as pyridine derivatives that typically enter
into the nucleophilic additions and ring transformation
reactions [10–13].
Pyridines are the most stable against ring opening
among the six-membered electron-deficient heterocycles.
The first studied process of this type was the Zincke-
Koenig reaction [2], namely, the cleavage of a quaternizat-
ed pyridine ring effected by aromatic amines to afford
dianils of glutaconic dialdehyde. Quite a number of the
pyridine ring transformations under the action of nucleo-
philes was discovered lately [3, 4]. First of all a series of
new rearrangements should be mentioned, like amidine
rearrangement [5, 6], enamine rearrangement of pyridine
derivatives [3, 7], and the unusual reaction we discovered
of the ring transformation of nitropyridinium salts into
indoles [8, 9].
We formerly established [14–17] that pyridinium and
isoquinolinium salts and also pyridine an and isoquinoline
proper reacted with 4-methylpyridinium salts under the
action of methylammonium sulfite affording as a result
of the pyridine ring transformation a 4-phenylpyridine and
a 4-(2-naphthyl)pyridine in 57 and 62% yield respectively.
We report here on results of a study on the effect of
substituents in the pyridine ring of 4-methylpyridinium salt
on the reactivity in the ring transformation reaction of
the pyridine and isoquinoline derivatives. As the study
objects 4-methyl-2-phenylpyridinium and 4,4'-di
-
Scheme 1.
0H
,
0H
,
0H
1
1
,,E
,,
ꢀ0H1+ ꢁ 62
ꢀ0H1+ ꢁ 62
1
5
,
0H
1
5
1
5
, ꢀꢁ,E
,,, ꢀꢁ,,,E
,,,Fꢀꢁ,,,G
0H
ꢂ ꢀꢁFꢃꢀ
ꢂEꢀꢁGꢃꢄ
,ꢀꢁ,,,ꢀꢁ5ꢁ
1
1070-4280/05/4111-1678Ó2005 Pleiades Publishing, Inc.

REACTIVITY OF 4-METHYLPYRIDINIUM SALTS
1679
Apparently the presence of a bulky susbtituent in the
position 2 of the pyridinium salt Ia and Ib favors the
competing reaction of N-demethylation of the initial salt
Ia and Ib leading to decreased yield of the target products.
This statement was indirectly confirmed by detection in
the reaction products with the use of TLC of 4,4'-di-
methyl-2,2'-dipyridyl and 4 methyl-2-phenylpyridine which
as we proved did not react with compounds IIa and IIb
under the conditions of the reaction in question.
methyl-2,2'-dipyridylium salts Ia and Ib were selected
(Scheme 1).
The quaternary salts of the heterocyclic bases Ia and
Ib required for this research were prepared in a 92%
yield by heating respectively 4-methyl-2-phenylpyridine
and 4,4'-dimethyl-2,2'-dipyridyl with methyl iodide in
a sealed ampule.
At heating a mixture of 1-methylpyridinium iodide (IIa)
or 2 methylisoquinolinium iodide (IIb) with 2-substituted
1,4-dimethylpyridinium iodide Ia and Ib in the presence
of methylammonium sulfite we obtained 4-arylpyridines
and 4-aryldipyridyls IIIa–IIId in 7–41% yields
(Scheme 1).
Prior to our studies no published evidence existed on
the ability of unsubstituted isoquinoline to take part in
reactions of pyridine ring transformation. In the preceding
article [17] we described the first instance of the pyridine
ring transformation in a non-quaternizated isoquinoline in
the course of its reaction with 1,4-dimethyl-pyridinium
iodide under the action of methylammonium sulfite
yielding 4-naphthylpyridine. The driving force of the
reaction is presumably the exchange of amine moiety for
methyl-amine in the intermadiate non-cyclic structure
(Scheme 3).
In keeping with the previously suggested mechanism
of this type reactions [15, 17] apparently the sulfite-ion
addition to salt IIa and IIb occurs thus distorting the
aromaticity of the pyridine ring followed by its opening.
The non-cyclic intermediate thus formed underwent
condensation promoted by a base with the active methyl
group of salt Ia and Ib which in the form of anhydro
base acts as a C-nucleophile in the process of the pyridine
ring transformation. The subsequent electrocyclic closure
leads to a benzene ring and to formation of a quaternary
salt of 4 arylpyridinium and 4-aryldipyridylium. The last
stage consists in the N demethylation of this quaternary
salt under a direct attack of a nucleophile on the Me–N
bond affording 4-aryl derivative IIIa–IIId (Scheme 2).
We found that at heating isoquinoline and salts Ia and
Ib with the water solution of methylammonium sulfite
4-naphthylpyridine (IIIc) formed in a 3% yield, and
4 naphthyldipyridyl (IIId) in a 22% yield. Thus the intro-
duction of a substituent into the position 2 of the 1,4-di-
methylpyridinium salt reduced the yields of the target
products IIIc and IIId compared to that of 4-naphthyl-
pyridine in [17].
It was presumable that isoquinoline derivatives would
prove to be more active than pyridine derivatives in the
nucleophilic reactions of the pyridine ring transformation.
Actually, in reactions with pyridinium salts Ia and Ib
containing a substituent in the position 2 of the pyridine
ring we observed this trend: The corresponding 4-naphthyl
derivatives IIIc and IIId were obtained in considerably
greater yields that the 4-phenyl derivatives IIIa and IIIb.
The structure of all compounds obtained was establish-
ed with the use of 1H and 13C NMR spectra, in particular,
those registered in the two-dimensional mode COSY and
NOESY. The composition was supported by elemental
analysis and mass spectra.
Dipyridyls and and arylpyridines constitute an important
class of heterocyclic compounds whose derivatives are
Scheme 2.
0H
1
5
,
0H
ꢀ0H1+ ꢁ 62
1+0H
, ꢀꢁ,E
1
B
0H1+
,
0H
,, ꢀꢁ,,E
1
5
1
5
1
5
B
,
,
,,, ꢁꢁꢁ,,,G
0H
0H
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

GROMOV et al.
1680
Scheme 3.
+
+
1+
ꢀ0H1+ ꢁ 62
0H1+ 2 6
0H1+ 2 6
1
1
2
+
0H
1ꢂ
5
,
+
0H
1+0H
2
0H1+
, ꢀꢁ,E
0H1+ 2 6
1
5
,,,Fꢀꢁ,,,G
and 125.76 MHz respectively at 25–30°C from solutions
in CDCl3 and DMSO d6 using solvent signals for internal
reference. 2D homonuclear 1H–1H COSY, NOESY and
applied as ligands in the complexes of transition metals,
also as fluorescent and biologically active compounds,
and in preparation of liquid crystals [18–20]. Nowadays
the main approaches to the synthesis of 2,2'-dipyridyls
and their 4-aryl derivatives consist in various versions of
coupling of simple pyridines, Hantzsch sythesis, and
Michael reaction [21–23]. In its turn the main procedures
for the synthesis of 4-arylpyridines are alternative versions
of Suzuki reaction, of free-radical arylation, and regio-
selective addition of Grignard reagents. The application
of Chichibabin reaction was described only for the
industrial production of 4 phenylpyridine. However in most
cases the 4 arylpyridines and unsymmetrical 4-aryl-2,2'-
dipyridyls are difficultly accessible for the listed proce-
dures are relatively expensive, toxic, and originate from
difficultly available initial compounds; the target products
must be isolated from a mixture with hard-to-separate
side reaction products [24–29].
1
heteronuclear H–13C COSY (HSQC, HMBC) spectra
served for assignment of proton and carbon signals.
Chemical shifts were measured with an accuracy of
0.01ppm, coupling constants were good to 0.1Hz. Mass
spectra were taken on Varian MAT-311A instrument,
high-resolution mass spectra were measured on Finnigan
MAT 8430 instrument using perfluorokerosene as
standard, ionizing electrons energy 70 eV, a direct
admission of the sample into the ion source. The reaction
progress was monitored by TLC on DCAlufolen Kiesel-
gel 60 F254 (Merck) plates. The column chromatography
was carried out using silica gel Kieselgel 60 (0.063–
0.100 mm) (Merck). 4,4'-Dimethyl-2,2'-dipyridyl was
purchased fromAldrich. 4-Methyl-2-phenylpyridine was
obtained as described in [30].
Thus we established that introducing in position 2 of
4-methylpyridinium salt of aryl or hetaryl groups did not
prevent the formation of 4-arylpyridines and 4-aryldi-
pyridyls. Simultaneously a simple and convenient method
was developed for preparation from available compounds
of 4 naphthyl derivatives of 2,2'-dipyridyl and pyridine in
good yield and of high purity. The naphthyl derivatives
of dipyridyl and pyridine are promising for testing as
fluorescent ligands and luminophors.
1,4-Dimethyl-2-phenylpyridinium iodide (Ia). To
0.338 g (2 mmol) of 4-methyl-2 phenylpyridine was added
5 ml (80 mmol) of methyl iodide. The mixture was heated
in a sealed ampule on an oil bath at 100°C for 10 h. Then
the reaction mixture was evaporated, the residue was
boiled with benzene, and benzene was on cooling decant-
ed, the residue was dried in a vacuum. Yield 0.570 g
(92%), mp 130–132°C. 1H NMR spectrum (DMSO d6,
30°C), d, ppm: 2.63 s (3, Me), 4.04 s (3 H, NMe), 7.65 m
(5H, Ph), 7.95 s (1H, H3 of pyridine), 7.97 br.d (1H, H5
of pyridine, J 6.4 Hz), 8.95 d (1H, H6 of pyridine,
J 6.4 Hz). Found, %: C 50.08; H 4.51; N 4.35. C13H14IN.
Calculated, %: C 50.18; H 4.53; N 4.50.
EXPERIMENTAL
1H and 13C NMR spectra were registered on a spec-
trometer Bruker DRX-500 at operating frequencies 500.13
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

REACTIVITY OF 4-METHYLPYRIDINIUM SALTS
1681
1,4,4'-Trimethyl-2,2'-dipyridylium iodide (Ib). To
0.370 g (2 mmol) of 4,4'-dimethyl-2,2'-dipyridyl was added
5 ml (80 mmol) of methyl iodide. The mixture was heated
in a sealed ampule on an oil bath at 100°C for 20 h. The
separated precipitate was filtered off and recrystallized
from a mixture benzene–methanol, 1:1. Yield 0.597 g
(92%), mp 190–191°C (from benzene–methanol, 1:1).
1H NMR spectrum (CDCl3, 25°C), d, ppm: 2.53 s (3H,
MeC4 of methylpyridyl), 2.73 s (3 H, MeC4 of pyridine),
4.43 s (3 H, NMe of pyridine), 7.35 m (1 H, H5 of methyl-
pyridyl), 7.82 br.s (1 H, H3 methylpyridyl), 7.90 br.s (1H,
H3 of pyridine), 7.95 m (1H, H5 of pyridine), 8.62 d (1H,
H6 of methylpyridyl, J 4.8 Hz), 9.38 d (1 H, H6 of pyridine,
J 6.3 Hz). Found, %: C 47.97; H 4.48; N 8.61. C13H15IN2.
Calculated, %: C 47.87; H 4.64; N 8.59.
benzene–ethyl acetate, 2:1. Yield 30 mg (12%), mp 72–
74°C. 1H NMR spectrum (CDCl3, 30°C), d, ppm: 2.46 s
(3 H, Me), 7.16 d (1 H, H5 of methylpyridyl, J 4.7
Hz), 7.43–7.46 m (1 H, H4 of phenyl), 7.48–7.51 m (2H,
H3, H5 of phenyl), 7.54 d.d (1 H, H5 of pyridine, J 5.1,
J 1.4 Hz), 7.78 d (2 H, H2, H6 of phenyl, J 7.5 Hz),
8.30 br.s (1 H, H3 of methylpyridyl), 8.57 d (1 H, H6 of
methylpyridyl, J 4.7 Hz), 8.68 br.s (1 H, H3 of pyridine),
8.73 d (1 H, H6 of pyridine, J 5.1 Hz). 13C NMR spectrum
(CDCl3, 30°C), d, ppm: 21.38 (Me), 119.43 (C3 of
pyridine), 121.74 (C3 of methylpyridyl), 122.32 (C5 of
pyridine), 124.99 (C5 of methylpyridyl), 127.36 (C2, C6 of
phenyl), 129.20 and 129.22 (C3, C5, C4 of phenyl), 138.51
(C1 of phenyl), 148.39 (C4 of methylpyridyl), 149.17 (C6
of methylpyridyl), 149.59 (C4 of pyridine), 149.74 (C6 of
pyridine), 156.09 (C2 of methylpyridyl), 156.97 (C2 of
pyridine). Mass spectrum, m/z (Irel, %): 246 (100) [M]+,
247 (19), 245 (37), 219 (4), 218 (11), 217 (3), 154 (7), 127
(4), 123 (4), 65 (2). Found, %: C 82.87; H 5.76; N 11.12.
C17H14N2. Calculated, %: C 82.90; H 5.73; N 11.37.
2,4-Diphenylpyridine (IIIa). To 0.105 g (5 mmol)
of 1-methylpyridinium iodide (IIa) and 0.312 g (1 mmol)
of compound Ia dissolved in 0.2 ml of water was added
10.8 ml of 40% water solution of MeNH2 and 5.2 ml of
68% solution of MeNH3HSO3. The reaction mixture in
a sealed ampule placed in a metal pressure reactor was
heated for 60 h to 230°C on a bath with Wood’s alloy. On
opening the ampule the reaction mixture was diluted with
water and extracted with benzene. The extract was dried
over MgSO4 and evaporated in a vacuum. The residue
was purified by column chromatography on SiO2 eluting
first with hexane, then with a mixture hexane–ethyl
acetate, 2:1. Yield 16 mg (7%), mp 69–70°C (from
4-(2-Naphthyl)-2-phenylpyridine (IIIc). To
1.355 g (5 mmol) of 2 methylisoquinolinium iodide (IIb)
and 0.311 g (1 mmol) of compound Ia dissolved in 0.2 ml
of water was added 5.4 ml of 40% water solution of
MeNH2 and 2.6 ml of 68% solution of MeNH3HSO3.
The reaction mixture in a sealed ampule placed in a metal
pressure reactor was heated for 40 h to 190°C on a bath
with silicone oil. On opening the ampule the reaction
mixture was diluted with water and extracted with
benzene. The extract was dried over MgSO4 and
evaporated in a vacuum. The residue was purified by
column chromatography on SiO2. Elution was performed
first with benzene, then with a mixture benzene–ethyl
acetate, 20:1. Then the chromatography on SiO2 was
repeated eluting with a mixture hexane–pyridine, 15:1.
Yield 0.101 g (39%), mp 62–63°C. 1H NMR spectrum
(CDCl3, 28°C), d, ppm: 7.48 m (1, H4 of phenyl), 7.54–
7.57 m (4 H, H5, H3 of phenyl, H6, H7 of naphthyl),
7.63 m (1 H, H5 of pyridine), 7.83 d (1 H, H3 of naphthyl,
J8.5 Hz), 7.92 m (1, H5 of naphthyl), 7.97 m (1 H, H8 of
naphthyl), 8.00 d (1, H4 of naphthyl, J 8.5 Hz), 8.09 br.s
(1H, H3 of pyridine), 8.10 m (2, H2, H6 of phenyl),
8.20 br.s (1, H1 of naphthyl), 8.81 d (1 H, H6 of pyridine,
J4.9 Hz). 13C NMR spectrum (CDCl3, 30°C), d, ppm:
118.96 (C3 of pyridine), 120.41 (C5 of pyridine), 124.55
(C3 of naphthyl), 126.48 (C1 of naphthyl), 126.67 (C7 of
naphthyl), 126.83 (C6, C9 of naphthyl), 127.09 (C2, C6 of
phenyl), 127.70 (C5 of naphthyl), 128.42 (C8 of naphthyl),
128.78 (C3, C5 of phenyl), 128.93 (C4 of naphthyl), 129.15
1
hexane) [23]. H NMR spectrum (CDCl3, 25°C), d, ppm:
7.49 m (5, H3, H5 of phenyls, H3 of pyridine), 7.53 m (1,
H5 of pyridine), 7.60 m (2 H, H4 of phenyls), 7.72 m (1,
H6 of pyridine), 7.82 m (4, H2, H6 of phenyls).
4'-Methyl-4-phenyl-2,2'-dipyridyl (IIIb). To
0.663 g (3 mmol) of 1-methylpyridinium iodide (IIa) and
0.326 g (1 mmol) of compound Ib dissolved in 1.5 ml of
water was added 1.5 ml of 40% water solution of MeNH2
and 1.3 ml of 68% solution of MeNH3HSO3. The reaction
mixture in a sealed ampule placed in a metal pressure
reactor was heated for 60 h to 230°C on a bath with
Wood’s alloy. On opening the ampule the reaction mixture
was diluted with water and extracted with benzene. The
extract was dried over Na2SO4 and evaporated in a
vacuum. The residue was purified by column chromato-
graphy on SiO2. As eluent was first used a mixture
ethanol–acetic acid, 4:1, then ethanol. The obtained
4-phenyldipyridyl IIIb was washed with a water solution
of Na2CO3 and extracted into benzene. The extract was
evaporated in a vacuum, and the residue was for the
second time subjected to chromatography on SiO2, eluent
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 11 2005

GROMOV et al.
1682
(C4 of phenyl), 134.45 (C10 of naphthyl), 135.58 (C2 of
naphthyl), 139.13 (C1 of phenyl), 149.46 (C4 of pyridine),
149.79 (C6 of pyridine), 157.91(C2 of pyridine). Mass
spectrum, m/z (Irel, %): 281 (100) [M]+, 280 (52), 278 (6),
252 (7), 204 (7), 176 (3), 152 (3), 149 (8), 140 (5), 139
(5). High resolution mass spectrum, [M]+, m/z: found
281.1201. C21H15N. Calculated M 281.1204.
1981, vol. 37, p. 3423.
4. Van der Plas, H. C., J. Heterocyclic Chem., 2000, vol. 37,
p. 427.
5. Wahren, M. Z., Chem., 1969, vol. 7, p. 241.
6. ElAshry, E.S.H., El Kilany, Y., Rashed, N., andAssafir, H.,
Adv.Heterocyclic Chem., 1999, vol. 75, p. 79.
7. Gromov, S.P. and Kost,A.N., Heterocycles, 1994, vol. 38,
p. 1127.
4-Methyl-4'-(2-naphthyl)-2,2'-dipyridyl (IIId). To
0.273 g (1 mmol) of 2 methylisoquinolinium iodide (IIb)
and 0.328 g (1 mmol) of compound Ib dissolved in 0.2 ml
of water was added 5.4 ml of 40% water solution of
MeNH2 and 2.6 ml of 68% solution of MeNH3HSO3.
The reaction mixture in a sealed ampule placed in a metal
pressure reactor was heated for 40 h to 190°C on a bath
with silicone oil. On opening the ampule the reaction
mixture was diluted with water and extracted with
benzene. The extract was dried over MgSO4 and
evaporated in a vacuum. The residue was purified by
column chromatography on SiO2. The product was eluted
first with a mixture hexane–pyridine, 15:1, then hexane–
pyridine, 10:1. Yield 0.121 g (41%), mp 120–121°C
8. Gromov, S.P. and Bundel’, Yu.G., Dokl. Akad. Nauk SSSR,
1985, vol. 281, p. 585.
9. Gromov, S.P., Heterocycles, 2000, vol. 53, p. 1607.
10. Bunting, J.W. and Meathrel, W.G., Canad. J. Chem., 1972,
vol. 50, p. 917.
11. Zoltewicz, J.A., Helmick, Z.S., and O’Holloran, J.K., J. Org.
Chem., 1976, vol. 41, p. 1308.
12. Zincke, Th., Weisspfenning G. Ann., 1913, vol. 396, p. 103.
13. Tamura, J. and Tsujimoto, N., Chem. Ind., 1972, p. 926.
14. Gromov, S.P. and Kurchavov, N.A., RF Patent 2150466,
2000; Byull. .Izobr., 2000, no. 16.
15. Gromov, S.P. and Kurchavov, N.A., Eur. J. Org. Chem., 2002,
p. 4123.
16. Gromov, S.P. and Fomina, M.V., RF Patent 2214401, 2003;
Byull. Izobr., 2003, no. 29.
17. Gromov, S.P. and Fomina, M.V., Izv.Akad.Nauk,Ser.Khim.,
2004, p. 864.
18. Stanforth, S.P., Tetrahedron, 1998, vol. 54, p. 263.
19. Speciale, S.G., Liang, C.L., Sonsalla, P.K., Edwards, R.H.,
and German, D.C., Neuroscience, 1998, vol. 84, p. 1177.
20. Mel’nikov, N., Novikov, E., and Khaskin, V., Khimiya i
biologicheskaya aktivnost’ dipyridilov i ikh proizvod-
nykh (Chemistry and BiologicalActivity of Dipyridyls and
Its Derivatives), Moscow: Khimiya, 1975.
21. Sasse, W.H.F., Org. Synth., 1966, vol. 46, p. 5.
22. Kuffner, F. and Straberger, F., Monatsh., 1957, vol. 88,
p. 793.
23. Krohnke, F., Synthesis, 1976, p. 1.
24. Katritzky, A.R., Beltrami, H., and Sammes, M.P., J. Chem.
Soc., Perkin Trans. 1, 1980, p. 2480.
25. Martinez-Barrasa, V., de Viedma,A., Garcia Burgos, C., and
Alvarez-Builla, J., Org. Lett., 2000, vol. 2, p. 3933.
26. Lohse, O., Theverin, P., and Waldvogel, E., Synlett., 1999,
p. 45.
27. Fenger, I., and Le Drian, C., Tetrahedron Lett., 1998, vol. 39,
p. 4287.
1
(from hexane). H NMR spectrum (CDCl3, 25°C), d,
ppm: 2.46 s (3 H, Me), 7.16 d (1 H, H5 methylpyridyl,
J 4.5 Hz), 7.54 m (2 H, H6, H7 of naphthyl), 7.65 m (1H,
H5 of pyridine, J 5 Hz), 7.88 and 7.95 2 m (4H, H3, H8,
H4, H5 of naphthyl), 8.26 s (1 H, H1 of naphthyl), 8.33 C
(1H, H3 of methylpyridyl), 8.60 d (1 H, H6 of methylpyridyl,
J 4.5 Hz), 8.76 d (1H, H6 of pyridine, J 5 Hz), 8.81 C
(1H, H3 of pyridine). 13C NMR spectrum (CDCl3, 25°C),
d, ppm: 21.15 (Me), 119.21 (C3 of pyridine), 121.67 (C5
of pyridine), 122.08 (C3 of methylpyridyl), 124.65 (C3 of
naphthyl), 124.77 (C5 of methylpyridyl), 126.52 (C7, C1
of naphthyl), 126.68 (C6 of naphthyl), 127.63 (C5 of
naphthyl), 128.45 and 128.74 (C4, C8 of naphthyl), 133.42
(C9, C10 of naphthyl), 135.43 (C2 of naphthyl), 148.12
(C4 of methylpyridyl), 148.95 (C6 of methylpyridyl), 149.15
(C4 of pyridine), 149.56 (C6 of pyridine), 155.86 (C2 of
methylpyridyl), 156.77 (C2 of pyridine). Mass spectrum,
m/z (Irel, %): 296 (100) [M]+, 295 (62), 294 (8), 268 (15),
204 (18), 176 (6), 148 (12), 147 (5), 65(5), 58 (40). Found,
%: C 85.10; H 5.42; N 9.53. C21H16N2. Calculated, %:
C 85.11; H5.44; N 9.45.
28. Avots, A.A., Lavrinovich, E.S., Lazdin’sh, I.Ya., and
Sile, M.K., USSR Inventor’s Certificate 512209, 1976; SSSR
Byull. Izobr., 1976, no. 16.
29. Avots, A.A., Lazdin’sh, I.Ya., Sile, M.K., and Lavrino-
vich, E.S., USSR Inventor’s Certificate 527425, 1977; SSSR
Byull. Izobr.,1977, no. 33.
REFERENCES
1. Van der Plas, H.C., Ring Transformations of Heterocycles,
New York:Academic Press, 1973.
30. Levin, R. and Osuch, C., J. Am. Chem. Soc., 1956, vol. 78,
p. 1723.
2. Becher, J., Synthesis, 1980, p. 589.
3. Kost,A. N., Gromov, S. P., and Sagitullin, R. S., Tetrahedron,
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 41 No. 11 2005