Preparation of 5,6-diaryl-2,2-bipyridines using a 1,2,4-triazine methodology

Article abstract of DOI:10.1007/s11172-015-0951-1

New unsymmetric 5,6-diaryl-2,2-bipyridines were synthesized in high yields using a 1,2,4-triazine methodology. Their photophysical properties were studied.

Full text of DOI:10.1007/s11172-015-0951-1

Russian Chemical Bulletin, International Edition, Vol. 64, No. 4, pp. 897—900, April, 2015
897
Preparation of 5,6´ꢀdiarylꢀ2,2´ꢀbipyridines using a 1,2,4ꢀtriazine methodology
D. S. Kopchuk,a,b N. V. Chepchugov, G. A. Kim, G. V. Zyryanov,a,b I. S. Kovalev,a
a
a,b
V. L. Rusinov, and O. N. Chupakhina,b
a,b
aUral Federal University named after the first President of Russia B. N. Eltsin,
1
9 ul. Mira, 620002 Ekaterinburg, Russian Federation.
Phone: +7 (343) 375 4501. Eꢀmail: gvzyryanov@gmail.com
I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences,
b
2
0 ul. S. Kovalevskoi, 620219 Ekaterinburg, Russian Federation.
Phone: +7 (343) 374 1189. Eꢀmail: chupakhin@ios.uran.ru
New unsymmetric 5,6´ꢀdiarylꢀ2,2´ꢀbipyridines were synthesized in high yields using a 1,2,4ꢀtriꢀ
azine methodology. Their photophysical properties were studied.
Key words: 1,2,4ꢀtriazine, Diels—Alder reaction, 5,6´ꢀdiarylꢀ2,2´ꢀbipyridines.
2
,2´ꢀBipyridines and 1,10ꢀphenanthrolines bearing
erocyclization of 1,2ꢀdiketones B with amidrazone C deꢀ
1
1,12
aromatic substituents at positions 5 and 6´ are of interest
as ligand fragments for transition metal cations,
preparation of promising photoluminescent materials,
as well as catalysts. In supramolecular chemistry, the
scribed earlier
(Scheme 1). Therefore, first it is necesꢀ
1
—5
for
6
sary to synthesize 5ꢀarylꢀ2ꢀcyanopyridine D to further conꢀ
vert it to amidrazone C.
7
fragments of the arylꢀsubstituted 2,2´ꢀbipyridines and
Scheme 1
1
,10ꢀphenanthrolines are used for the design of some
8
cyclophanes. In this case, the absence of a substituent at
position 6 usually has a positive effect on the coordination
properties of the compound.
As for the approaches to the synthesis of such comꢀ
pounds, there are only few literature examples of their
preparation using, for example, crossꢀcoupling reacꢀ
tions1
,4,6,8
or sequential nucleophilic substitution of hyꢀ
drogen and crossꢀcoupling reactions.5
,7
In the present work, we suggest a synthetic approach
to unsymmetric 2,2´ꢀbipyridines bearing aromatic subꢀ
stituents at positions 5 and 6´ and having no substituents
at position 6. To accomplish the task, we applied twice
a methodology for the preparation of substituted pyridines
via their 1,2,4ꢀtriazine analogs, which at present are very
successfully used in the synthesis of various substituted
Analysis of literature data showed that 5ꢀarylꢀ2ꢀcyanoꢀ
pyridines can be prepared, for example, by the introꢀ
duction of aromatic fragments in pyridines using crossꢀ
9
,10
pyridines.
It is obvious that the preparation of the target comꢀ
pounds required the development of a convenient method
for the synthesis of their 1,2,4ꢀtriazine analogs A (Scheme 1).
The most acceptable approach to their synthesis was a hetꢀ
1
3,14
coupling reactions,
a direct cyanation of 3ꢀarylpyꢀ
(however, 2ꢀcyanoꢀsubstituted
1
5
ridine Nꢀoxides
compounds are frequent side products ), a nucleophilic
1
6
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 0897—0900, April, 2015.
066ꢀ5285/15/6404ꢀ0897 © 2015 Springer Science+Business Media, Inc.
1

898
Russ.Chem.Bull., Int.Ed., Vol. 64, No. 4, April, 2015
Kopchuk et al.
Scheme 2
1
2
1
2
R , R = biphenylꢀ2,2´ꢀdiyl (a), R = R = Ph (b)
Reagents and conditions: i. 2,5ꢀnorbornadiene, oꢀxylene, 143 C, 10 h; ii. 85% formic acid, reflux, 20 h; iii. SOCl , reflux, 3 h, then
2
aqueous ammonia, 5—10 C, 1 h; iv. POCl , reflux, 1.5 h; v. hydrazine hydrate, ethanol—THF (1 : 1), 3 days; vi. ethanol—THF (7 : 3),
3
reflux, 10 h; vii. 1ꢀmorpholinocyclopentene, 200 C, 3 h.
substitution for the halogen atom with the cyano group,17
as well as by a sequence of transformations acid—amide—
nitrile.18
necessary to note that the annulation of the fused cycloꢀ
alkene fragment to the pyridine ring usually leads to the inꢀ
crease in the solubility of compounds in organic solvents.
24
In our opinion, the preparation of 5ꢀarylꢀ2ꢀcyanoꢀ
pyridines via 5ꢀarylpyridineꢀ2ꢀcarboxylic acids is the most
convenient method of all the approaches considered. In
the framework of this work, we developed a new approach
to the synthesis of these compounds, which also uses
In the course of the work, we studied photophysical
properties of new ligands 8a and 8b, the results are given in
Table 1, the luminescence spectra are shown in Fig. 1.
In particular, the data obtained show that the presence
of an additional phenyl ring in the pyridine fragment of
pyridylmonoazatriphenylene significantly shifts both the
luminescence and absorption maxima to the longer waveꢀ
length region as compared to the unsubstituted comꢀ
pound. Besides, the replacement of the monoazatriꢀ
phenylene fragment with the pyridyl one with two separate
phenyl rings led to a considerable increase in the emission
intensity and a hypsochromic shift of the luminescence
and absorption maxima.
1
9,20
a 1,2,4ꢀtriazine methodology. Thus, earlier authors
described an efficient method for the preparation of
ꢀarylꢀ3ꢀtrichloromethylꢀ1,2,4ꢀtriazines having no substitꢀ
6
2
6
uents at position 5 by the reaction of isonitrosoacetophenꢀ
one hydrazones with trichloroacetonitrile iminoester obꢀ
tained in situ. It is known that a trichloromethyl group can
undergo a number of transformations interesting from the
2
1,22
point of view of further functionalization of pyridine.
Following a procedure described earlier, we obtained
ꢀtrichloromethylꢀ6ꢀphenylꢀ1,2,4ꢀtriazine (1), which was
In conclusion, in the present work we suggested an
efficient synthetic approach to the preparation of 5,6´ꢀdiꢀ
arylꢀ6Hꢀ2,2´ꢀbipyridines, which are poorly available by
3
converted to the corresponding pyridine 2 by the azaꢀDiꢀ
els—Alder reaction with 2,5ꢀnorbornadiene (Scheme 2).
It should be noted that earlier the preparation of 2ꢀtriꢀ
chloromethylpyridine derivatives by this method was not
described. Further, carboxylic acid 3 was obtained by the
hydrolysis of the trichloromethyl group, then it was conꢀ
verted to amide 4 (using a simplified version of the method
Table 1. Quantum yield of luminescence (), absorption
(Amax) and luminescence (Imax) maxima in acetonitrile for
compounds 8a,b
1
8
Comꢀ
pound
/nm
*
suggested in the work ), which was dehydrated upon treatꢀ
ment with POCl (carried out according to the described
3
Amax
Imax
1
8
procedure ) to yield 2ꢀcyanoꢀ5ꢀphenylpyridine (5). The
latter was converted to amidrazone 6, which reacted with
8
а
b
206, 223 sh, 253, 271,
92 sh, 312 sh, 326, 380
211, 236 sh, 283, 350
473
0.174
0.699
2
1
,2ꢀdiketones to give 1,2,4ꢀtriazine analogs of the target
8
425
compounds 7 in good yields. Finally, the azaꢀDiels—Alder
reaction with 1ꢀmorpholinocyclopentene as a dieneophile
according to an efficient procedure suggested earlier in the
literature23 resulted in the required ligands 8. It is also
*
Quantum yields for all the compounds were measured relꢀ
ative to quinine sulfate ( = 0.546 in 0.1 N aqueous solution
25
of H SO ).
2
4

The synthesis of nonꢀsymmetrical bipyridines
Russ.Chem.Bull., Int.Ed., Vol. 64, No. 4, April, 2015
899
I (arb. units)
5ꢀPhenylpyridineꢀ2ꢀcarboxamide (4). Acid 3 (0.62 g, 3.12 mmol)
was suspended in thionyl chloride (40 mL), and the mixture was
refluxed for 3 h. The solvent was evaporated at reduced pressure,
aqueous ammonia (30 mL) was added to the residue, and the
mixture obtained was stirred for 1 h with cooling in an ice bath.
A precipitate formed was filtered off, washed with water, and
dried in vacuo. The product was used in the next step without
3
3
2
2
1
1
50
00
50
00
50
00
8
8
b
a
1
additional purification. The yield was 0.53 g (85%). H NMR
(
DMSOꢀd ), : 7.39—7.46 (m, 1 H, Ph); 7.46—7.58 (m, 3 H,
6
Ph, NH); 7.67—7.75 (m, 2 H, Ph); 7.85 (br.s, 1 H, NH); 8.10—8.19
m, 2 H, H(3) and H(4)); 8.84 (d, 1 H, H(6), J = 2.5 Hz). MS
(
+
(ESI), m/z: 199.09 [M + H] .
ꢀPhenylpyridineꢀ2ꢀcarboxamide hydrazone (6). Cyanopyrꢀ
5
5
0
idine 5 (0.5 g, 2.77 mmol) was dissolved in a mixture of ethanol—
THF (1 : 1, 50 mL), followed by the addition of hydrazine hyꢀ
drate (190 L, 3.9 mmol). The mixture obtained was allowed to
stand at room temperature for 3 days. The solvents were evapoꢀ
rated at reduced pressure, the residue was treated with diethyl
ether, a precipitate formed was filtered off and dried. The prodꢀ
uct was used in the next step without additional purification. The
4
00
450
500
550
600
650 /nm
Fig. 1. Luminescence spectra of bipyridines 8.
1
other methods, and studied photophysical properties of
new compounds.
yield was 440 mg (75%). H NMR (DMSOꢀd6), : 5.65 (br.s, 2 H,
NH ); 7.35—7.40 (m, 1 H, Ph); 7.44—7.50 (m, 2 H, Ph);
2
7
.63—7.68 (m, 2 H, Ph); 7.93 (dd, 1 H, H(4), J = 7.9 Hz,
J = 2.5 Hz); 8.00 (d, 1 H, H(3), J = 7.9 Hz); 8.71 (d, 1 H, H(6),
J = 2.5 Hz). MS (ESI), m/z: 213.11 [M + H] .
Experimental
+
Synthesis of 1,2,4ꢀtriazines 7 (general procedure). Amidraꢀ
zone 6 (250 mg, 1.18 mmol) was dissolved in ethanol (30 mL),
followed by the addition of a solution of the corresponding 1,2ꢀdiꢀ
one (1.18 mmol) in a mixture of ethanol—THF (1 : 1, 50 mL).
The resulting mixture was refluxed for 10 h and cooled to room
temperature. A precipitate formed was filtered off, washed with
ethanol, and dried. An analytical sample was obtained by recrysꢀ
tallization from ethanol.
1H and 13C NMR spectra were recorded on a Bruker Avanceꢀ
00 spectrometer (400 MHz and 100 MHz, respectively), using
4
SiMe as an internal standard. Melting points were measured on
4
a Boetius apparatus. Electrospray ionization mass spectra were
recorded on a Bruker Daltonics Series MicrOTOFꢀQ II (Breꢀ
men, Germany). Elemental analysis was performed on a Perkin
Elmer Model PE 2400, Series II CHN analyzer. Absorption
spectra were recorded on a Shimadzu UVꢀ2401PC spectroꢀ
photometer. Luminescence spectra were recorded on a Varian
Cary Eclipse fluorimeter. 3ꢀTrichloromethylꢀ5ꢀphenylꢀ1,2,4ꢀtriꢀ
azine (1)19 and 2ꢀcyanoꢀ5ꢀphenylpyridine (5) were obtained
according to the described procedures.
3ꢀ(5ꢀPhenylpyridinꢀ2ꢀyl)phenanthro[9,10ꢀe]ꢀ1,2,4ꢀtriazine
(7a). The yield was 270 mg (60%), m.p. > 250 C. Found (%):
C, 81.14; H, 4.02; N, 14.39. C H N . Calculated (%): C, 81.23;
2
6
16
4
18
1
H, 4.20; N, 14.57. H NMR (DMSOꢀd ), : 7.44—7.50 (m, 1 H,
6
Ph); 7.53—7.59 (m, 2 H, Ph); 7.80—7.91 (m, 4 H); 7.92—7.98
5
ꢀPhenylꢀ2ꢀtrichloromethylpyridine (2). Triazine 1 (3 g,
(m, 1 H); 7.98—8.04 (m, 1 H); 8.32 (d, 1 H, HPy(3), J = 8.1 Hz);
1
0.93 mmol) was suspended in oꢀxylene (40 mL), followed by
8.78—8.85 (m, 2 H); 8.89 (dd, 1 H, H (4), J = 8.1 Hz, J = 2.3 Hz);
Py
the addition of 2,5ꢀnorbornadiene (3.3 mL, 32.79 mmol) and
reflux of the mixture for 10 h. The solvent was evaporated at
reduced pressure, the residue was purified by column chromatoꢀ
graphy (silica gel, eluent chloroform). The yield was 2.23 g (75%),
m.p. 198—200 C. Found (%): C, 52.73; H, 2.81; N, 4.93.
9.17 (d, 1 H, HPy(6), J = 2.3 Hz); 9.43—9.50 (m, 2 H, H(5) and
H(12)). MS (ESI), m/z: 385.15 [M + H] .
+
5,6ꢀDiphenylꢀ3ꢀ(5ꢀphenylpyridinꢀ2ꢀyl)ꢀ1,2,4ꢀtriazine (7b).
The yield was 230 mg (50%), m.p. 189—191 C. Found (%):
C, 80.71; H, 4.56; N, 14.57. C H N . Calculated (%): C, 80.81;
2
6
16
4
1
1
C H ClN. Calculated (%): C, 52.88; H, 2.96; N, 5.14. H NMR
H, 4.69; N, 14.50. H NMR (DMSOꢀd ), : 7.37—7.51 (m, 7 H, Ph);
12
8
6
(
DMSOꢀd ), : 7.42—7.48 (m, 1 H, Ph); 7.49—7.55 (m, 2 H,
7.51—7.57 (m, 2 H, Ph); 7.58—7.63 (m, 2 H, Ph); 7.64—7.70
(m, 2 H, Ph); 7.78—7.84 (m, 2 H, Ph); 8.27 (dd, 1 H, HPy(4),
J = 8.3 Hz, J = 2.3 Hz); 8.68 (d, 1 H, HPy(3), J = 8.3 Hz); 9.12
(d, 1 H, HPy(6), J = 2.3 Hz). MS (ESI), m/z: 387.16 [M + H]+.
Synthesis of bipyridines 8 (general procedure). A mixture of
the corresponding triazine 7 (0.25 mmol) and 1ꢀmorpholinoꢀ
cyclopentene (0.2 mL, 1.25 mmol) was stirred for 2 h at 200 C
under argon. Then, 1ꢀmorpholinocyclopentene (0.1 mL,
0.625 mmol) was added and the stirring was continued for anꢀ
other 1 h in the same regime. Afterwards, the reaction mixture
was cooled to room temperature and diluted with acetonitrile,
the resulting mixture was heated to boiling, then cooled to room
temperature. A precipitate formed was filtered off, washed with
acetonitrile, and dried. An analytical sample was obtained by
recrystallization from acetonitrile.
6
Ph); 7.72—7.77 (m, 2 H, Ph); 8.12 (d, 1 H, H(3), J = 7.9 Hz);
8
J = 2.5 Hz). MS (ESI), m/z: 271.98 [M + H] .
ꢀPhenylpyridineꢀ2ꢀcarboxylic acid (3). Trichloromethylpyꢀ
ridine 2 (1 g, 3.67 mmol) was suspended in 85% aqueous formic
acid (25 mL), and the mixture was refluxed for 20 h. The solvent
was evaporated at reduced pressure, the residue was treated with
hexane, a precipitate formed was filtered off, washed with hexꢀ
ane, and dried. The product was used in the next step without
.23 (dd, 1 H, H(4), J = 7.9 Hz, J = 2.5 Hz); 8.95 (d, 1 H, H(6),
+
5
1
additional purification. The yield was 0.62 g (85%). H NMR
(
DMSOꢀd ), : 7.43—7.49 (m, 1 H, Ph); 7.49—7.55 (m, 2 H,
6
Ph); 7.74—7.79 (m, 2 H, Ph); 8.18 (d, 1 H, H(3), J = 7.9 Hz);
.28 (dd, 1 H, H(4), J = 7.9 Hz, J = 2.5 Hz); 8.97 (d, 1 H, H(6),
8
–
J = 2.5 Hz). MS (ESI), m/z: 198.06 [M – H] .

900
Russ.Chem.Bull., Int.Ed., Vol. 64, No. 4, April, 2015
Kopchuk et al.
1
0ꢀ(5ꢀPhenylpyridinꢀ2ꢀyl)ꢀ12,13ꢀdihydroꢀ11Hꢀdibenzo[f,h]ꢀ
7. Y. Nishikawa, H. Yamamoto, J. Am. Chem. Soc., 2011,
133, 8432.
cyclopenta[c]quinoline (8a). The yield was 90 mg (84%), m.p.
70—172 C. Found (%): C, 87.94; H, 5.11; N, 6.48. C H N .
Calculated (%): C, 88.12; H, 5.25; N, 6.63. H NMR (CDCl ),
: 2.27 (m, 2 H, CH (12)); 3.68 (t, 2 H, CH (11), J = 7.6 Hz); 3.74
2 2
t, 2 H, CH (13), J = 7.6 Hz); 7.41—7.47 (m, 1 H, Ph); 7.49—7.56
1
8. K. I. Arias, E. ZysmanꢀColman, J. C. Loren, A. Lindena,
J. S. Siegel, Chem. Commun., 2011, 47, 9588.
9. A. M. Prokhorov, D. N. Kozhevnikov, Chem. Heterocycl.
Compd. (Engl. Transl.), 2012, 48, 1153 [Khim. Geterotsikl.
Soedin., 2012, 1237].
31
22
2
1
3

(
(
2
m, 2 H, Ph); 7.62—7.76 (m, 6 H); 8.12 (dd, 1 H, HPy(4),
J = 8.3 Hz, J = 2.3 Hz); 8.58—8.63 (m, 1 H); 8.63—8.68 (m, 1 H);
.69—8.73 (m, 1 H); 8.78 (d, 1 H, HPy(3), J = 8.3 Hz); 8.99 (d, 1 H,
HPy(6), J = 2.3 Hz); 9.53 (m, 1 H, H(8)). 13C NMR (CDCl ),
10. G. R. Pabst, O. C. Pfüller, J. Sauer, Tetrahedron, 1999,
55, 8045.
11. R. Metze, Chem. Ber., 1956, 89, 2056.
8
3

1
1
: 26.1, 33.3, 37.4, 122.4, 123.1, 123.3, 123.5, 126.1, 126.6, 127.2,
27.3, 127.8, 128.1, 128.3, 129.1, 130.1, 130.7, 131.1, 131.8,
12. F. H. Case, J. Org. Chem., 1965, 30, 931.
13. Pat. US/0149510 A1, 2009.
14. L. Hu, R. K. Arafa, M. A. Ismail, A. Patel, M. Munde,
W. D. Wilson, T. Wenzler, R. Brun, D. W. Boykin, Bioorg.
Med. Chem., 2009, 17, 6651.
34.7, 135.5, 138.0, 138.9, 144.9, 146.9, 149.9, 152.0, 157.6. MS
+
(
ESI), m/z: 423.19 [M + H] .
3
,4ꢀDiphenylꢀ1ꢀ(5ꢀphenylpyridinꢀ2ꢀyl)ꢀ6,7ꢀdihydroꢀ5Hꢀcycloꢀ
penta[c]pyridine (8b). The yield was 80 mg (74%), m.p. 138—140 C.
15. A. C. Benniston, Tetrahedron Lett., 1997, 38, 8279.
16. T. Sakamoto, S. Kaneda, S. Nishimura, H. Yamanaka, Chem.
Pharm. Bull., 1985, 33, 565.
Found (%): C, 87.62; H, 5.57; N, 6.44. C H N . Calculatꢀ
3
1
24
2
1
ed (%): C, 87.70; H, 5.70; N, 6.60. H NMR (CDCl ), : 2.12
3
(
m, 2 H, CH (6)); 2.85 (t, 2 H, CH (7), J = 7.6 Hz); 3.59 (t, 2 H,
17. A. Breteche, P. Marchand, M.ꢀR. Nourrisson, P. Hauteꢀ
faye, G. De Nanteuil, M. Duflos, Tetrahedron, 2011,
67, 4767.
2
2
CH (5), J = 7.6 Hz); 7.15—7.23 (m, 5 H, Ph); 7.25—7.33 (m, 3 H,
Ph); 7.38—7.45 (m, 3 H, Ph); 7.47—7.53 (m, 2 H, Ph); 7.65—7.70
2
(
m, 2 H, Ph); 8.01 (dd, 1 H, HPy(4), J = 8.3 Hz, J = 2.3 Hz);
18. A. I. Pavlyuchenko, V. V. Titov, N. I. Smirnova, V. T.
Grachev, Chem. Heterocycl. Compd. (Engl. Transl.), 1980,
16, 681 [Khim. Geterotsikl. Soedin., 1980, 888].
19. D. N. Kozhevnikov, N. N. Kataeva, V. L. Rusinov, O. N.
Chupakhin, Russ. Chem. Bull. (Int. Ed.), 2004, 53, 1243 [Izv.
Akad. Nauk, Ser. Khim., 2004, 1243].
8
.50 (d, 1 H, H (3), J = 8.3 Hz); 8.94 (d, 1 H, HPy(6), J = 2.3 Hz).
Py
13
C NMR (CDCl ), : 25.4, 32.9, 33.7, 123.2, 127.0, 127.1,
3
1
1
27.3, 127.6, 128.0, 128.2, 129.1, 129.9, 130.2, 132.6, 134.7,
35.3, 138.0, 138.8, 140.7, 147.0, 150.0, 154.5, 155.8, 157.4.
+
MS (ESI), m/z: 425.20 [M + H] .
2
0. D. N. Kozhevnikov, V. N. Kozhevnikov, V. L. Rusinov,
O. N. Chupakhin. Chem. Heterocycl. Compd. (Engl. Transl.),
1999, 35, 1377 [Khim. Geterotsikl. Soedin., 1999, 1574].
This work was financially supported by the Ministry of
Education and Science of the Russian Federation (State
Contract 8430), the President of the Russian Federaꢀ
tion Council for Grants (Program for State Support
of Young Scientists of the Russian Federation, Grant
MKꢀ3079.2015.3), as well as by the Government of
the Russian Federation (Program 211, Agreement
No. 02.A03.21.0006).
21. L. J. Allen, S. H. Lee, Y. Cheng, P. S. Hanley, J. M. Muhuꢀ
hi, E. Kane, S. L. Powers, J. E. Anderson, B. M. Bell, G. A.
Roth, M. S. Sanford, D. C. Bland, Org. Process Res. Dev.,
2
014, 18, 1045.
2
2
2. J. Coates, P. G. Sammes, R. M. West, J. Chem. Soc., Perkin
Trans. 2, 1996, 7, 1275.
3. V. N. Kozhevnikov, M. M. Ustinova, P. A. Slepukhin,
A. Santoro, D. W. Bruce, D. N. Kozhevnikov, Tetrahedron
Lett., 2008, 49, 4096.
4. D. S. Kopchuk, Ph.D. Thesis (Chem.), UGTUꢀUPI, Ekatꢀ
erinburg, 2010, 122 pp. (in Russian).
5. W. H. Melhuish, J. Phys. Chem., 1961, 65, 229.
6. D. S. Kopchuk, A. F. Khasanov, I. S. Kovalev, G. A. Kim,
I. L. Nikonov, G. V. Zyryanov, V. L. Rusinov, O. N. Chupaꢀ
khin, Chem. Heterocycl. Compd. (Engl. Transl.), 2014, 50,
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