Chemistry of Heterocyclic Compounds

, Volume 48, Issue 8, pp 1272–1274

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

Authors

    • North Caucasus Federal University
  • N. A. Aksenov
    • North Caucasus Federal University
  • A. B. Kumshaeva
    • North Caucasus Federal University
  • A. N. Smirnov
    • North Caucasus Federal University
  • O. N. Nadein
    • North Caucasus Federal University
Article

DOI: 10.1007/s10593-012-1132-x

Cite this article as:
Aksenov, A.V., Aksenov, N.A., Kumshaeva, A.B. et al. Chem Heterocycl Comp (2012) 48: 1272. doi:10.1007/s10593-012-1132-x

Keywords

3,8-dihydropyrido[2',3,'4':4,5]naphtho[1,8-de][1,2,3]triazin-7(6H)-ones1H-naphtho[1,8-de][1,2,3]triazineβ-nitrostyrenespolyphosphoric acid1,2,3,6-tetraazapyrenesaminationperi-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 [13].

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 β-nitrostyrenes.

We have shown that reaction of naphthotriazine 1 with a 1.05-fold molar excess of β-nitrostyrenes 2a-c for 3 h in PPA at 65-70°C 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 β-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 β-nitrostyrene 2a-c

(1.05 mmol) in 80% PPA (2–3 g) was heated for 3 h at 65-70°C with vigorous stirring. The reaction 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.
https://static-content.springer.com/image/art%3A10.1007%2Fs10593-012-1132-x/MediaObjects/10593_2012_1132_Figa_HTML.gif
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 (37%); mp > 295°C (decomp., BuOH). 1H NMR spectrum, δ, 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). Yield 0.121 g (32%); mp > 300°C (decomp., BuOH). 1H NMR spectrum, δ, 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). Yield 0.079 g (23%); mp > 300°C (decomp., BuOH). 1H NMR spectrum, δ, 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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© Springer Science+Business Media New York 2012