Synthesis of novel 1,2,3,6-tetraazapyrene heterocyclic system representatives - 3,8-dihydropyrido[2',3',4':4,5]naphtho-[1,8-de][1,2,3]triazin- 7(6h)-ones

Full text of DOI:10.1007/s10593-012-1132-x

Chemistry of Heterocyclic Compounds, Vol. 48, No. 8, November, 2012 (Russian Original Vol. 48, No. 8, August, 2012)
SYNTHESIS OF NOVEL 1,2,3,6-TETRAAZAPYRENE
HETEROCYCLIC SYSTEM REPRESENTATIVES –
3,8-DIHYDROPYRIDO[2',3',4':4,5]NAPHTHO-
[1,8-de][1,2,3]TRIAZIN-7(6H)-ONES
A. V. Aksenov1*, N. A. Aksenov1, A. B. Kumshaeva1,
A. N. Smirnov1, and O. N. Nadein1
Keywords: 3,8-dihydropyrido[2',3,'4':4,5]naphtho[1,8-de][1,2,3]triazin-7(6H)-ones, 1H-naphtho[1,8-de]-
[1,2,3]triazine, -nitrostyrenes, polyphosphoric acid, 1,2,3,6-tetraazapyrenes, amination, peri-annelation.
Amongst the few azapyrenes synthesized to this time, a series of compounds have been found having
useful properties as organic luminophores, dyes, and effective medicines [1-3].
The poor availability of azapyrenes probably is mostly due to the absence of efficient methods for the
peri-annelation of heterocyclic rings. In this work, we propose a method for the peri-annelation of an
[ab]pyridine ring to the 1H-naphtho[1,8-de][1,2,3]triazine (1) through its reaction with -nitrostyrenes.
We have shown that reaction of naphthotriazine 1 with a 1.05-fold molar excess of -nitrostyrenes 2a-c
for 3 h in PPA at 65-70ºC gives the previously unknown 8-aryl-3,8-dihydropyrido[2',3',4':4,5']naphtho[1,8-de]-
[1,2,3]triazin-7(6H)-ones 6a-c in 23-37% yields.
The reaction mechanism probably includes successive alkylation of the naphthotriazine 1 by the
-nitrostyrenes 2a-c to form the nitro compounds 3a-c and an intramolecular variant of our recently discovered
acetamidation reaction of aromatic compounds by nitroalkanes in PPA [4, 5]. The oximes 5a-c are formed as
intermediates and subsequently undergo a Beckmann rearrangement.
Hence the methodology reported in this work has allowed us to develop a synthetic method for
previously unknown representatives of the 1,2,3,6-tetraazapyrene system.
1H NMR spectra were recorded on a Bruker DRX-500 instrument (500 MHz) using DMSO-d6 with
TMS as internal standard. Elemental analysis was carried out on a KOVO CHN-1 CHN analyzer. Melting
points were determined on a PTP-M apparatus (Khimlaborpribor). Monitoring of the reaction course and the
purity of the synthesized compounds was carried out on Silufol UV-254 plates with EtOAc as eluent.
Commercial PPA with an 80% P2O5 content was used.
8-Aryl-3,8-dihydropyrido[2',3',4':4,5]naphtho[1,8-de][1,2,3]triazin-7(6H)-ones 6a-c (General Method).
A mixture of 1H-naphtho[1,8-de][1,2,3]triazine (1) (0.169 g, 1 mmol) and the corresponding -nitrostyrene 2a-c
(1.05 mmol) in 80% PPA (2-3 g) was heated for 3 h at 65-70ºC with vigorous stirring. The reaction
_______
*To whom correspondence should be addressed, e-mail: alexaks05@rambler.ru.
1North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russia.
_________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1364-1365, August, 2012.
Original article submitted April 4, 2012.
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0009-3122/12/4808-1272©2012 Springer Science+Business Media New York

mixture was poured into water (30 ml), neutralized with ammonia solution, and extracted with butanol (350 ml).
The extract was filtered through an L40/100 silica gel layer (d = 50 mm, l = 30 mm) and most of the butanol
was evaporated. The virtually pure compound 6a-c precipitated upon cooling.
N
N
N
NH
N
NH
N
NH
N
Ar
NO2
PPA
2a–c
PPA
65–70°C
3 h
OH
+
N
1
NO2
Ar
N
Ar
O
P
3a–c
4a–c
O
HO
OH
N
N
NH
NH
N
PPA
–H3PO4
NH
OH
Ar
Ar
N
5a–c
O
6a–c
2–6 a Ar = Ph, b Ar = 4-BrC6H4, c Ar = 4-O2NC6H4
8-Phenyl-3,8-dihydropyrido[2',3',4':4,5]naphtho[1,8-de][1,2,3]triazin-7(6H)-one (6a). Yield 0.111 g
1
(37%); mp > 295ºC (decomp., BuOH). H NMR spectrum, , ppm (J , Hz): 5.02 (1H, s, H-8); 6.49 (1H, br. d,
J = 7.7, H-10); 6.53 (1H, br. d, J = 8.1, H-4); 7.04-7.32 (6H, m, H-5, Н Ph); 7.38 (1H, d, J = 7.7, H-9); 9.88
(1H, br. s, NHСО); 11.04 (1H, br. s, NH). Found, %: C 72.18; H 3.92; N 18.69. C18H12N4O. Calculated, %:
C 71.99; H 4.03; N 18.66.
8-(4-Bromophenyl)-3,8-dihydropyrido[2',3',4':4,5]naphtho[1,8-de][1,2,3]triazin-7(6H)-one
(6b).
1
Yield 0.121 g (32%); mp > 300ºC (decomp., BuOH). H NMR spectrum, , ppm (J , Hz): 5.02 (1H, s, H-8);
6.46 (1H, br. d, J = 7.7, H-10); 6.51 (1H, br. d, J = 8.1, H-4); 7.09 (2H, d, J = 8.1, H-2',6'); 7.23 (1H, d, J = 8.1,
H-5); 7.34 (1H, d, J = 7.7, H-9); 7.44 (2H, d, J = 8.1, H-3',5'); 9.86 (1H, br. s, NHСО); 11.02 (1H, br. s, NH).
Found, %: C 57.18; H 2.83; N 14.69. C18H11BrN4O. Calculated, %: C 57.01; H 2.92; N 14.77.
8-(4-Nitrophenyl)-3,8-dihydropyrido[2',3',4':4,5]naphtho[1,8-de][1,2,3]triazin-7(6H)-one
(6c).
1
Yield 0.079 g (23%); mp > 300ºC (decomp., BuOH). H NMR spectrum, , ppm (J , Hz): 5.07 (1H, s, H-8);
6.48 (1H, br. d, J = 7.7, H-10); 6.58 (1H, br. d, J = 8.1, H-4); 7.28 (1H, d, J = 8.1, H-5); 7.41 (1H, d, J = 7.7,
H-9); 7.47 (2H, d, J = 8.4, H-2',6'); 8.15 (2H, d, J = 8.4, H-3',5'); 9.88 (1H, br. s, NHСО); 11.04 (1H, br. s, NH).
Found, %: C 62.77; H 3.17; N 20.22. C18H11N5O3. Calculated, %: C 62.61; H 3.21; N 20.28.
This work was carried out within the scope of the Federal Targeted Program "Scientific and Scientific-
pedagogical Personnel of Innovative Russia" 2009-2113 (state contract 16.740.11.0162) and with the financial
support of the Russian Foundation for Basic Research (grant 10-03-00193a).
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