The formation of the pyridine ring in the synthesis of dipyrido-[3′, 2′:4,5]thieno[3,2-b: 3,2-d]pyridines [2]

Full text of DOI:10.1007/s10593-006-0251-7

Chemistry of Heterocyclic Compounds, Vol. 42, No. 10, 2006
THE FORMATION OF THE PYRIDINE
RING IN THE SYNTHESIS OF DIPYRIDO-
[3',2':4,5]THIENO[3,2-b:3,2-d]PYRIDINES
V. K. Vasilin1, M. M. Lipunov1, L. D. Konyushkin2, E. A. Kaigorodova1, and G. D. Krapivin1
Keywords: 3-aminothieno[2,3-b]pyridines, dipyrido[3',2':4,5]thieno[3,2-b:3,2-d]pyridines.
While continuing our investigations into the reactivity of substituted 3-aminothieno[2,3-b]pyridines [1,
2], we found a new reaction leading to closure of the pyridine ring during the formation of a pentacyclic
heteroaromatic 22π-electronic system dipyridothienopyridine.
During an attempt to reduce the carbonyl group of compounds 1a-d with sodium borohydride in ethanol
the corresponding dipyrido[3',2':4,5]thieno[3,2-b:3,2-d]pyridines 3a-d were isolated from the reaction mixture
instead of the expected amino alcohols 2. The mechanism of the transformations that occur is not quite clear and
will be the subject of further investigations.
MeO
NH2
OH
MeO
S
R
NH2
Me
N
N
2
O
R
NaBH4
R
MeO
S
Me
N
N
S
1a–d
N
S
Me
Me
OMe
3a–d
1, 3 a R = Ph; b R = C6H4Br-4; c R = C6H3Cl2-2,4; d R = Me
The 1H NMR spectra were recorded in trifluoroacetic acid (compounds 3a-c) and DMSO-d6 (compound
3d) on a Bruker DRX-500 instrument (500 MHz).
Synthesis (General Procedure). Compound 1 (0.005 mol) was dissolved by heating in ethanol (20 ml),
and sodium borohydride (7.5 mmol) was added while the reaction mixture was stirred. The obtained solution
was boiled for 3 h, cooled, and neutralized with a 10% solution of hydrochloric acid. The flocculent precipitate
was separated and washed with boiling DMF, water, and ethanol. The products were recrystallized from ethanol.
__________________________________________________________________________________________
1
Kuban State Technological University, Krasnodar, Russia; e-mail: organics@kubstu.ru.
2
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow; e-mail:
Leonid@chemical-block.com. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10,
pp. 1582-1583, 2006. Original article submitted June 30, 2005. Revision submitted February 28, 2006.
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0009-3122/06/4210-1368©2006 Springer Science+Business Media, Inc.

4,9-di(methoxymethyl)-6,11-Dimethyl-2-phenyldipyrido[3',2':4,5]thieno[3,2-b:3,2-d]pyridine (3a).
Yield 23%; mp >350°C. 1H NMR spectrum, δ, ppm: 3.15 (6H, s, CH3); 4.01 (6H, s, OCH3); 6.11 (4H, s, OCH2);
7.80-7.90 (5H, m, HPh); 8.36 (2H, s, HPy). Mass spectrum (EI, 70 eV), m/z (Irel, %): 485 [M]+ (30), 470
[M - CH3]+ (72), 438 [M - CH3 - CH3OH]+ (31), 410 [M - CH3 - CH3OH - CO]+ (63), 369 [M - CH3 - CH3OH -
CO - C3H5]+ (16), 205 [M - C17H14NOS]+ (100). Found, %: C 66.85; H 4.73; N 8.62. C27H23N3O2S2.
Calculated, %: C 66.78; H 4.77; N 8.65.
2-(4-Bromophenyl)-4,9-di(methoxymethyl)-6,11-dimethyldipyrido[3',2':4,5]thieno[3,2-b:3,2-d]-
1
pyridine (3b). Yield 27%; mp 316-317°C. H NMR spectrum, δ, ppm (J, Hz): 2.97 (6H, s, CH3); 3.84 (6H, s,
OCH3); 5.97 (4H, s, OCH2); 7.53 (2H, d, J = 8.0, 3,5-HAr); 7.78 (2H, d, J = 8.0, 2,6-HAr); 8.18 (2H, s, HPy). Mass
spectrum* (EI, 70 eV), m/z (Irel, %): 548 [M - CH3]+ (9), 488 [M - CH3 - CH3OH - CO]+ (6), 44 [CS]+ (100).
Found, %: C 57.50; H 3.90; N 7.41. C27H22BrN3O2S2. Calculated, %: C 57.45; H 3.93; N 7.44.
2-(2,4-Dichlorophenyl)-4,9-di(methoxymethyl)-6,11-dimethyldipyrido[3',2':4,5]thieno[3,2-b:3,2-d]-
1
pyridine (3c). Yield 26%; mp >350°C. H NMR spectrum, δ, ppm (J, Hz): 2.71 (6H, s, CH3); 3.68 (6H, s,
OCH3); 5.62 (4H, s, OCH2); 7.64-7.76 (3H, m, HAr); 7.96 (2H, s, HPy). Mass spectrum*2 (EI, 70 eV),
m/z (Irel, %): 553 [M]+ (28), 538 [M-CH3]+ (100), 506 [M - CH3 - CH3OH]+ (41), 478 [M - CH3 - CH3OH - CO]+
(88), 423 [M - CH3 - CH3OH - CO - C4H7]+ (10), 408 [M - CH3 - CH3OH - CO - C4H7 - CH3]+ (32). Found, %:
C 58.57; H 3.79; N 7.54. C27H21Cl2N3O2S2. Calculated, %: C 58.48; H 3.82; N 7.58.
4,9-Di(methoxymethyl)-2,6,11-trimethyldipyrido[3',2':4,5]thieno[3,2-b:3,2-d]pyridine
(3d).
1
Yield 23%; mp 305-306°C. H NMR spectrum, δ, ppm: 2.71 (6H, s, CH3); 2.83 (3H, s, CH3); 3.65 (6H, s,
OCH3); 5.56 (4H, s, OCH2); 7.61 (2H, s, HPy). Found, %: C 62.30; H 5.01; N 9.88. C22H21N3O2S2. Calculated, %:
C 62.39; H 5.00; N 9.92.
REFERENCES
1.
2.
V. K. Vasilin, E. A. Kaigorodova, and G. D. Krapivin, Khim. Geterotsikl. Soedin., 565 (2000). [Chem.
Heterocycl. Comp., 36, 494 (2000)].
E. A. Kaigorodova, V. K. Vasilin, L. D. Konyushkin, E. B. Usova, and G. D. Krapivin, Molecules, 1085
(2000).
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* The isotopic peaks for 79Br are given.
*2 The isotopic peaks for 35Cl are given.
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