Synthesis of 1h-1,5,7-triaza- cyclopenta[c,d]phenalenes, a new heterocyclic system

Full text of DOI:10.1007/s10593-010-0481-6

Chemistry of Heterocyclic Compounds, Vol. 46, No. 1, 2010
SYNTHESIS OF 1H-1,5,7-TRIAZA-
CYCLOPENTA[c,d]PHENALENES,
A NEW HETEROCYCLIC SYSTEM
A. V. Aksenov1**, A. S. Lyakhovnenko1, and N. C. Karaivanov1
Keywords: sodium azide, perimidines, PPA, 1H-1,5,7-triazacyclopenta[c,d]phenalenes, peri annela-
tion, Schmidt reaction.
In previous work [1-4], we have developed a number of methods for the peri annelation of
six-membered rings to give perimidines. In light of the high biological activity of a significant number of indole
derivatives, we propose a method for the peri annelation of the pyrrole ring to perimidines. The reaction of
ketones 1a-c (1 mmol) and NaN3 (0.07 g, 1.08 mmol) in PPA* (2-3 g) at 70-80°C for 1 h and then at 150-160°C
for 4 h monitored by thin-layer chromatography leads to 1H-1,5,7-triazacyclopenta[c,d]phenalenes 3a-c in
36-48% yield.
The reaction involves intermediante formation of amides 2a-c, which cam be isolated, for example 2a.
The 1H NMR spectra were taken on a Bruker WP-200 spectrometer at 200 MHz in DMSO-d6 with TMS
as the internal standard. The reaction course and purity of the products obtained were monitored on
Silufol UV-254 plates with 1:1 ethyl acetate–ethanol as the eluent.
R
R
R
N
NH
O
N
NH
N
N
NaN3
PPA
∆
N
H
R1
HN
R1
O
R1
3a–c
1a–c
2a–c
1–3 a R = H, R1 = Me, b R = R1 = Me, c R = Me, R1 = Ph
_______
*The PPA sample used containing 86% P2O5 was prepared according to Uhlig [5].
** To whom correspondence should be addressed, e-mail: k-biochem-org@stavsu.ru.
1Stavropol State University, Stavropol 355009, Russia.
__________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 146-147, January, 2010. Original
article submitted November 9, 2009.
0009-3122/10/4601-0127©2010 Springer Science+Business Media, Inc.
127

The reaction mixture was treated with 50 ml water and then brought to pH 8-9 by adding ammonium
hydroxide. The precipitate formed was filtered off and the mother liquor was extracted with three 50-ml benzene
portions. The solvent was distilled off and the residue was combined with the precipitate. The products obtained
were purified by recrystallization.
6(7)-Acetaminoperimidine (2a) was obtained in 86% yield; mp 225-226°C (ethyl acetate). 1H NMR, δ,
ppm (J, Hz): 2.08 (3H, s, COCH3); 6.43 (2H, m, H-4(9), H-9(4)); 7.03 (1H, d, J = 8.5, H-7(6)); 7.15 (1H, dd,
J = 8.5, J = 7.3, H-8(5)); 7.24 (1H, d, J = 8.1, H-7(6)); 7.32 (1H, s, H-2); 9.21 (1H, br. s, NHCO); 10.61 (1H,
br. s, NH). Found, %: C 69.45; H 4.86; N 18.61. C13H11N3O. Calculated, %: C 69.32; H 4.92; N 18.65.
2-Methyl-1H-1,5,7-triazacyclopenta[c,d]phenalene (3a) was obtained in 44% yield (0.091 g);
mp 259-260°C (benzene). 1H NMR spectrum, δ, ppm (J, Hz): 2.98 (3H, s, CH3); 7.58 (1H, d, J = 9.0, H-9); 7.78
(1H, d, J = 9.0, H-3); 8.31 (1H, d, J = 9.0, H-4); 8.47 (1H, d, J = 9.0, H-8); 9.36 (1H, s, H-6); 13.1 (1H, br. s,
NH). Found, %: C 75.54; H 4.31; N 20.15. C13H9N3. Calculated, %: C 75.35; H 4.38; N 20.28.
2,6-Dimethyl-1H-1,5,7-triazacyclopenta[c,d]phenalene (3b) was obtained in 48% yield (0.106 g);
1
mp 271-272°C (benzene). H NMR spectrum, δ, ppm (J, Hz): 2.87 (3H, s, 2-CH3), 2.95 (3H, s, 6-CH3), 7.50
(1H, d, J = 9.0, H-9); 7.67 (1H, d, J = 9.0, H-3); 8.24 (1H, d, J = 9.0, H-4); 8.41 (1H, d, J = 9.0, H-8); 12.8 (1H,
br. s, NH). Found, %: C 76.18; H 4.95; N 18.87. C14H11N3. Calculated, %: C 76.00; H 5.01; N 18.99.
6-Methyl-2-phenyl-1H-1,5,7-triazacyclopenta[c,d]phenalene (3c) was obtained in 36% yield
1
(0.102 g); mp 291-292°C (benzene). H NMR spectrum, δ, ppm (J, Hz): 2.92 (3H, s, CH3); 7.49 (1H, t, J = 7.7,
H-4 Ph); 7.49 (2H, t, J = 7.7, H-3, H-5 Ph); 7.68 (1H, d, J = 9.0, H-9); 7.81 (1H, d, J = 9.0, H-3); 8.19 (2H, d,
J = 7.7, H-2, H-6 Ph); 8.34 (1H, d, J = 9.0, H-4); 8.73 (1H, d, J = 9.0, H-8); 12.9 (1H, br. s, NH). Found, %:
C 80.69; H 4.55; N 14.76. C19H13N3. Calculated, %: C 80.69; H 4.62; N 14.83.
This work was carried out with the financial support of the Russian Basic Research Fund
(Grant No. 10-03-00193a).
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