1,3,7-Triazapyrenes: The unexpected products of the reaction of 1,8-diaminonaphthalene with 1,3,5-triazines in polyphosphoric acid

Full text of DOI:10.1007/s11172-007-0373-9

Russian Chemical Bulletin, International Edition, Vol. 56, No. 11, pp. 2354—2355, November, 2007
2354
1,3,7ꢀTriazapyrenes: the unexpected products of the reaction
of 1,8ꢀdiaminonaphthalene with 1,3,5ꢀtriazines in polyphosphoric acid

I. V. Borovlev, A. V. Aksenov, I. V. Aksenova, and S. V. Pisarenko
Stavropol State University,
1a ul. Pushkina, 355009 Stavropol, Russian Federation.
Fax: +7 (865) 235 4033. Eꢀmail: nauka@stavsu.ru
Earlier,1 it was reported that the catalystꢀfree reaction
of 1,8ꢀdiaminonaphthalene (1) with 1,3,5ꢀtriazine (2a)
leads to perimidine. Our efforts to carry out the similar
reaction with 2,4,6ꢀtrimethylꢀ (2b) and 2,4,6ꢀtriphenylꢀ
1,3,5ꢀtriazine (2c) under the same conditions were unꢀ
successful. We suggested that this transformation can be
accomplished in polyphosphoric acid (PPA),* since the
similar cyclization of aromatic orthoꢀdiamines with carbꢀ
oxylic acids and their derivatives in PPA is known for
Scheme 1
* Polyphosphoric acid with 86% content of P2O5, obtained by
the known procedure,2 was used.
R = H (a), Me (b), Ph (c)
Scheme 2
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2275—2276, November, 2007.
1066ꢀ5285/07/5611ꢀ2354 © 2007 Springer Science+Business Media, Inc.

Synthesis of 1,3,7ꢀtriazapyrenes
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 11, November, 2007 2355
a long time.3 The reaction proceeds under heating of reꢀ
agents above 100 °С, however, the earlier unknown
1,3,7ꢀtriazapyrenes 3a—c unexpectedly turned out to be
the products of the reaction instead of the corresponding
perimidines (Scheme 1).
1,3,7ꢀTriazapyrene (3a). The yield was 0.09 g (44%), crysꢀ
tals yellow in color, m.p. 240—242 °C (from octane; with subl.).
Found (%): C, 76.22; H, 3.01; N, 20.28. C13H7N3. Calcuꢀ
lated (%): C, 76.08; H, 3.44; N, 20.48. 1H NMR (DMSOꢀd6), δ:
9.76 (s, 1 H, H(2)); 9.72 (s, 2 H, H(6), H(8)); 8.26, 8.80 (both d,
2 H each, H(4), H(10), H(5), H(9), J = 9.22 Hz).
A suggested mechanism of this transformation (with
compound 3a as the example) includes the formation of
perimidine (4), the electrophilic attack of 1,3,5ꢀtriazinium
cation at its position 6(7), the triazine ring opening with
the formation of intermediate 5, and the subsequent cyꢀ
clization of 5 at periꢀposition. The aromatization of interꢀ
mediate 6 proceeds through the elimination of amidine,
which undergoes hydrolysis during isolation (Scheme 2).
In conclusion, a oneꢀpot reaction of symꢀtriazines in
PPA with periꢀdiamine 1 leads not only to the closure of
the perimidine ring, but also to the periꢀannulation of the
[c,d]pyridine ring. Further, we are going to study the scope
of the reaction, in particular, with respect to perimidines
and other fused aromatic and heteroaromatic compounds.
2,6,8ꢀTrimethylꢀ1,3,7ꢀtriazapyrene (3b). The yield was
0.094 g (38%), crystals orange in color, m.p. 206—208 °C (from
octane; with subl.). Found (%): C, 77.87; H, 5.18; N, 16.72.
C
16H13N3. Calculated (%): C, 77.71; H, 5.30; N, 16.99. 1H NMR
(DMSOꢀd6), δ: 2.98 (s, 3 H, С(2)Me); 3.08 (s, 6 H, С(6)Me,
С(8)Me); 7.92, 8.67 (both d, 2 H each, H(4), H(10), H(5),
H(9), J = 9.40 Hz). 13C NMR (75 MHz, CDCl3), δ: 20.64
(2 C); 25.80 (1 C); 111.27 (1 C); 118.48 (2 C); 124.41 (1 C);
124.63 (2 C); 131.14 (2 C); 152.96 (2 C); 153.78 (2 C);
165.46 (1 C).
2,6,8ꢀTriphenylꢀ1,3,7ꢀtriazapyrene (3c). The yield was 0.13 g
(30%), crystals yellowꢀbrownish in color, m.p. 286—288 °C
(from ethanol). Found (%): C, 86.09; H, 4.21; N, 9.49.
C31H19N3. Calculated (%): C, 85.89; H, 4.42; N, 9.69.
1H NMR (CDCl3), δ: 7.61 (m, 9 H, C(2)Ph, C(6)Ph, C(8)Ph,
mꢀH and pꢀH); 7.95 (br.d, 4 H, C(6)Ph, C(8)Ph, oꢀH); 8.26,
8.76 (both d, 2 H each, H(4), H(10), H(5), H(9), J = 9.5 Hz);
8.84 (br.d, 2 H, C(2)Ph, oꢀH).
1
H and 13C spectra were recorded on a Bruker DRXꢀ500 and
Bruker AMꢀ300 spectrometers. Melting points were determined
in the sealed capillary tubes on a PTP instrument and were not
corrected. 1,8ꢀDiaminonaphthalene (Merck) was distilled
in vacuo before use. 1,3,5ꢀTriazine and 2,4,6ꢀtriphenylꢀ1,3,5ꢀ
triazine were commercially available from Aldrich; 2,4,6ꢀtriꢀ
methylꢀ1,3,5ꢀtriazine was obtained according to the known proꢀ
cedure.4
References
1. E. J. Grundmann and A. J. Kreutzberger, J. Am. Chem. Soc.,
1955, 77, 6559.
Synthesis of compounds 3a—c (general procedure). A mixꢀ
ture of 1,8ꢀdiaminonaphthalene (1) (0.158 g, 1 mmol), the corꢀ
responding triazine (2.5 mmol), and PPA (3—4 g) was vigorꢀ
ously stirred for 1 h at 100—105 °C (2a), 2 h at 140—145 °C (2b),
3 h at 180—185 °C (2c). The reaction mixture was cooled
to 80 °С, poured to cold water (30 mL) with stirring, and made
basic to pH ~8 with aqueous ammonia. The precipitate was
filtered off, dried in air, and recrystallized from octane (3a,b) or
ethanol (3c).
2. F. Uhlig, Angew. Chem., 1954, 66, 435.
3. D. W. Hein, R. J. Alheim, and J. J. Leavitt, J. Am. Chem. Soc.,
1957, 79, 427.
4. F. C. Schaefer and G. A. Peters, J. Org. Chem., 1961, 26, 2778.
Received April 24, 2007;
in revised form August 31, 2007