Novel three-component peri-annelation reactions of carbocyclic and pyridine rings with perimidines-synthesis of 1,3-diazapyrenes and 1,3,7-triazapyrenes

Article abstract of DOI:10.1016/j.tetlet.2008.01.064

A new effective synthetic method for 1,3-diazapyrenes and 1,3,7-triazapyrenes is developed based on the three-component reaction of perimidines or 1,8-diaminonaphthalene with 1,3,5-triazines and carbonyl compounds or benzonitrile in polyphosphoric acid (P

Full text of DOI:10.1016/j.tetlet.2008.01.064

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Tetrahedron Letters 49 (2008) 1808–1811
Novel three-component peri-annelation reactions of carbocyclic
and pyridine rings with perimidines—synthesis
of 1,3-diazapyrenes and 1,3,7-triazapyrenes
Alexander V. Aksenov *, Alexander S. Lyahovnenko, Inna V. Aksenova, Oleg N. Nadein
Stavropol State University, Pushkina Street 1, Stavropol 355009, Russian Federation
Received 6 November 2007; revised 29 December 2007; accepted 10 January 2008
Available online 15 January 2008
Abstract
A new effective synthetic method for 1,3-diazapyrenes and 1,3,7-triazapyrenes is developed based on the three-component reaction of
perimidines or 1,8-diaminonaphthalene with 1,3,5-triazines and carbonyl compounds or benzonitrile in polyphosphoric acid (PPA).
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords: Perimidines; 1,3,5-Triazines; Polyphosphoric acid; 1,3-Diazapyrenes; 1,3,7-Triazapyrenes
Polyazapyrenes belong to a potentially abundant but
still poorly understood class of polynuclear heteroaromatic
compounds. During recent years, synthetic methods, theo-
retical, and applied aspects of various azapyrenes have
been actively studied.1
Earlier, a series of methods for carbocyclic ring annela-
tion of naphthalenes and phenalenones was developed,2
which enabled the synthesis of phenalenones and pyrenes
including 1,3-diazapyrenes.3 These methods included the
reactions of naphthalene or phenalenone with unsaturated
carbonyl compounds and the condensation of two carbon-
yl compounds followed by ring closure. In the present
Letter, we report a new three-component carbocyclic ring
annelation of perimidines 1 using 1,3,5-triazines 2a–c and
carbonyl compounds 4 in polyphosphoric acid.
We propose that the addition of a carbonyl compound
to the reaction mixture may change the course of the
reaction in the direction of carbocyclic ring formation
(Scheme 2).
Indeed, reaction of 1 mmol of perimidine 1a–c with
2 mmol of 1,3,5-triazines 2a–c and 3 mmol of carbonyl
compound 4a–d in 3–4 g of PPA6 leads to the formation
of 1,3-diazapyrenes 6 in moderate yields, Table 1.
In a similar way, the reaction also proceeds with 1,8-di-
aminonaphthalene (7) with the yields indicated in Table 1
(Scheme 3). In this case 3 mmol of the triazine was
used.
Using this idea, we further hypothesized that the reac-
tion should be applicable for 1,3,7-triazapyrene synthesis.
Addition of benzonitrile instead of a carbonyl compound
to the reaction mixture may change the course of the
reaction in the direction of pyridine ring formation
(Scheme 4).
Indeed, the reaction of 1 mmol of perimidine 1a–c with
3 mmol of 1,3,5-triazine 2a and 5 mmol of benzonitrile in
3–4 g of PPA led to the formation of 1,3,7-triazapyrenes
8a–c in the yields indicated in Table 2. Diaminonaphtha-
lene 7 could also be used instead of perimidines 1, but in
this case, 3 mmol of triazine was required (Scheme 4).
Earlier, we have shown that 1,3,5-triazines in PPA are
effective reagents for the acylation of perimidines 14
(Scheme 1). At higher temperatures, ring opening occurs
in intermediate 3 resulting in the annelation of the triazine
and formation of 1,3,7-triazapyrenes.5
*
Corresponding author. Tel.: +7 865 235 9134; fax: +7 865 235 7023.
E-mail address: k-biochem-org@stavsu.ru (A. V. Aksenov).
0040-4039/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2008.01.064

A. V. Aksenov et al. / Tetrahedron Letters 49 (2008) 1808–1811
1809
R
R
R
N
R'
N
NH
N
NH
N
N
PPA
PPA
N
N
+
R'
N
R'
R'
N
1a-c
NH
R'
2a-c
R'
R'
R'
N
3
R=H (1a), Me (1b), Ph (1c)
R'=H (2a), Me (2b), Ph (2c)
H2O
N
R
NH
R'
O
Scheme 1. Perimidine acylation and 1,3,7-triazapyrene syntheses.
OH
OH
P
O
O
PPA
O
X
X
R''
R''
4a-d
5a-e
R
R
R
R
R
H
H
H
N+
H
N
N
N
N+
N
N
N
N
N
NH
NH
+
- R'
5a-e
H
3a-e
2
-R'CN
R''
O+
R'
R''
H
N+
H
R'
+
R'
R'
R'
-H
R'
N
N
-H PO
R''
R'
3
4
O
N
H
HO
2
N
HO
HO
N
NH
P
N
P
X
H
X
X
O
O
R'
N
R'
R'
N
HO
R'
6a-j
H N
R'
H
N
R'
2
2
Scheme 2. 1,3-Diazapyrene 6a–j synthesis from perimidines 3a–e.
Table 1
Synthesis of 1,3-diazapyrenes
NH2 NH2
2a-c, 4a-d
Entry
R
R0
R00
X
Product Yield (%), from
6a-j
PPA
1
7
7
1
2
3
4
5
6
7
8
9
H
H
H
H
H
H
H
Me
Ph
H
H
Me
H
H
H
6a
6b
6c
47
45
75
57
43
73
43
57
51
37
34
—
63
58
41
—
—
—
42
—
Me Me
Scheme 3. 1,3-Diazapyrene synthesis from 1,8-diaminonaphthalene 7.
H
H
H
Ph
Me COMe 6d
Me CO2Et 6e
In conclusion, the advantages of the method described
for carbocyclic and pyridine cycle peri-annelation include
reagent availability, experimental simplicity, and applica-
bility to the synthesis of a broad range of substituted diaza-
and triazapyrenes.7
Me Ph
Ph
H
H
H
6f
6g
Ph
Me CO2Et 6h
Ph 6i
Ph
H
10
Me Me COMe 6j

1810
A. V. Aksenov et al. / Tetrahedron Letters 49 (2008) 1808–1811
Aksenova, I. V.; Lyahovnenko, A. S.; Aksenov, A. V.; Borovlev, I. V.
R
Russ. J. Gen. Chem. 2007, 9, 1650.
N
N
4. (a) Aksenov, A. V.; Borovlev, I. V.; Lyahovnenko, A. S.; Aksenova, I.
V. Chem. Heterocycl. Compd. (Engl. Transl.) 2007, 4, 527; (b)
Aksenov, A. V.; Borovlev, I. V.; Lyahovnenko, A. S.; Aksenova, I.
V. Russ. J. Org. Chem. 2007, 10, 1579.
PhCN, 2a
1a-c
PPA
5. Aksenov, A. V.; Borovlev, I. V.; Aksenova, I. V.; Pisarenko, S. V.;
Kovalev, D. A. Tetrahedron Lett. 2008, 49, 707.
6. PPA containing 86% P2O5 was used; preparation according to: Uhlig,
F. Angew. Chem. 1954, 66, 435.
N
Ph
8a-c
7. General procedure: A mixture of compound 1 or 7 (1 mmol), 1,3,5-
triazine (2a–c) (2 mmol for 1 or 3 mmol for 7), carbonyl compound
(4a–d) (3 mmol) or benzonitrile (5 mmol) and PPA (3–4 g) was stirred
at 60–70 °C, for 9 h. The reaction mixture was poured into cold water
(25 ml) with vigorous stirring and ammonia was added to pH ꢀ 8. The
resulting precipitate was filtered off, washed with water, and dried. To
increase the yield, the filtrate was extracted with ethyl acetate
(3 ꢁ 50 ml) and the combined organics evaporated. Compounds 6
and 8 were purified by flash chromatography on silica gel, eluting with
ethyl acetate.
PhCN, 2a
7
8a
PPA
Scheme 4. 1,3,7-Triazapyrene 8a–c synthesis.
Table 2
Synthesis of 1,3,7-triazapyrene 8
Entry
R
Product
Yield (%), from
Data for 6-methyl-1,3-diazapyrene (6a): Mp 178–180 °C (ethyl acetate).
1H NMR (300 MHz, CDCl3):
d 3.11 (3H, s, Me); 8.04 (1H,
1
7
d, J = 7.67 Hz, 7-H); 8.20 (1H, d, J = 9.50 Hz, 9-H); 8.30 (1H, d,
J = 9.50 Hz, 5-H); 8.37 (1H, d, J = 7.67 Hz, 8-H); 8.55 (1H, d,
J = 9.50 Hz, 10-H); 8.82 (1H, d, J = 9.50 Hz, 4-H); 9.80 (1H, s, 2-H).
13C NMR (50 MHz, CDCl3): d 19.23, 125.97, 126.54, 127.61, 128.90,
129.16, 129.49, 131.00, 132.60, 134.41, 136.35, 138.62, 152.76, 153.28,
155.91. Anal. Calcd for C15H10N2: C, 82.55; H, 4.62; N, 12.83. Found:
C, 82.67; H, 4.56; N, 12.77.
Data for 6,8-dimethyl-1,3,7-triazapyrene (6b): Mp 207–209 °C (ethyl
acetate). 1H NMR (300 MHz, CDCl3): d 3.04 (6H, s, Me); 7.88 (1H, s,
7-H); 8.19 (2H, d, J = 9.46 Hz, 5/9-H); 8.74 (2H, d, J = 9.50 Hz, 4/10-
H); 9.73 (1H, s, 2-H). 13C NMR (50 MHz, CDCl3): d 19.56, 123.39,
125.29, 126.51, 132.36, 135.55, 137.93, 145.51, 153.45, 155.59. Anal.
Calcd for C16H12N2: C, 82.73; H, 5.21; N, 12.06. Found: C, 82.89; H,
5.15; N, 11.96.
Data for 6-phenyl-1,3-diazapyrene (6c): Mp 193–195 °C (ethyl acetate).
1H NMR (300 MHz, CDCl3): d 7.59–7.64 (5H, m, Ph); 8.15 (1H,
d, J = 7.72 Hz, 7-H); 8.32 (1H, d, J = 9.42 Hz, 5-H); 8.41 (1H, d,
J = 7.72 Hz, 8-H); 8.48 (1H, d, J = 9.42 Hz, 9-H); 8.76 (1H, d,
J = 9.42 Hz, 4-H); 8.98 (1H, d, J = 9.42 Hz, 10-H); 9.76 (1H, s, 2-H).
13C NMR (50 MHz, CDCl3): d 126.32, 126.98, 128.22, 128.72, 128.95,
129.17, 129.24, 129.32, 129.41, 130.76, 132.54, 134.23, 134.64, 136.28,
138.65, 152.41, 153.29, 156.75. Anal. Calcd for C20H12N2: C, 85.69; H,
4.32; N, 9.99. Found: C, 85.82; H, 4.25; N, 8.93.
1
2
3
H
Me
Ph
8a
8b
8c
75
71
74
72
—
—
References and notes
1. (a) Piantanida, I.; Tomisic, V.; Zinic, M. J. Chem. Soc., Perkin Trans. 2
2000, 375; (b) Palm, B. S.; Piantanida, I.; Zinic, M.; Schneider, H.-J. J.
Chem. Soc., Perkin Trans. 2 2000, 385; (c) Becker, H.-C.; Norden, B. J.
Am. Chem. Soc. 1997, 119, 5798; (d) Becker, H.-C.; Broo, A.; Norden,
B. J. Phys. Chem. 1997, 101, 8853; (e) Brun, A. M.; Harriman, A. J.
Am. Chem. Soc. 1991, 113, 8153; (f) Brun, A. M.; Harriman, A. J. Am.
Chem. Soc. 1992, 114, 3656; (g) Roknic, S.; Glavas-Obrovac, L.;
Karner, I.; Piantanida, I.; Zinic, M.; Pavelic, K. Chemotherapy 2000,
46, 143; (h) Piantanida, I.; Palm, B. S.; Zinic, M.; Schneider, H.-J. J.
Chem. Soc., Perkin Trans. 2 2001, 1808; (i) Steiner-Biocic, I.; Glavas-
Obrovac, L.; Karner, I.; Piantanida, I.; Zinic, M.; Pavelic, K.; Pavelic,
J. Anticancer Res. 1996, 16, 3705; (j) Balzani, V.; Credi, A.; Langford,
S. J.; Raymo, F. M.; Stoddart, J. F.; Venturi, M. J. Am. Chem. Soc.
2000, 122, 3542; (k) Borovlev, I. V.; Demidov, O. P. Chem. Heterocycl.
Compd. (Engl. Transl.) 2003, 11, 1417 (review).
2. (a) Kuroda, S.; Hirooka, S.; Tanaka, E.; Fukuyama, Y.; Tsuchida, T.;
Nakagawa, K. Bull. Chem. Soc. Jpn. 1989, 7, 2396; (b) Nenajdenko, V.
G.; Baraznenok, I. L.; Balenkova, E. S. Tetrahedron 1996, 40, 12993;
(c) Newman, M. S.; Khanna, V. K. J. Org. Chem. 1975, 40, 3283; (d)
Kappe, T. Tetrahedron Lett. 1968, 5327; (e) Jutz, C.; Kirchlechner, R.
Angew. Chem. 1966, 78, 493; (f) Frost, D. A.; Morrison, G. A. J. Chem.
Soc., Perkin Trans. 1 1973, 2159; (g) Lewis, I. K.; Topsom, R. D. Aust.
J. Chem. 1965, 923.
Data for 6-methyl-7-acetyl-1,3-diazapyrene (6d): Mp 161–163 °C (ethyl
acetate). 1H NMR (300 MHz, CDCl3): d 2.86 (3H, s, COMe); 3.14 (3H,
s, Me); 8.23 (1H, d, J = 9.13 Hz, 9-H); 8.31 (1H, d, J = 9.51 Hz, 5-H);
8.54 (1H, d, J = 9.13 Hz, 10-H), 8.55 (1H, s, 8-H); 8.90 (1H, d,
J = 9.51 Hz, 4-H); 9.83 (1H, s, 2-H). 13C NMR (50 MHz, CDCl3): d
16.31, 31.08, 123.82, 127.12, 127.34, 127.57, 127.63, 128.99, 132.75,
135.65, 136.07, 139.58, 153.43, 154.25, 156.62, 172.79, 203.28.
m
max(KBr)/cmꢂ1 1645 (C@O); Anal. Calcd for C17H12N2O: C, 78.44;
H, 4.65; N, 10.76. Found: C, 78.59; H, 4.58; N, 10.71.
3. (a) Edel, A.; Marnol, P. A.; Sauvage, J. P. Tetrahedron Lett. 1985, 727;
(b) Borovlev, I. V.; Aksenov, A. V.; Pozharskii, A. F. Chem.
Heterocycl. Compd. (Engl. Transl.) 1997, 11, 1367; (c) Demidov, O.
P.; Borovlev, I. V.; Pozharskii, A. F. Chem. Heterocycl. Compd. (Engl.
Transl.) 2001, 1, 127; (d) Demidov, O. P.; Borovlev, I. V.; Pozharskii,
A. F. Chem. Heterocycl. Compd. (Engl. Transl.) 2001, 8, 1046; (e)
Borovlev, I. V.; Demidov, O. P.; Pozharskii, A. F. Chem. Heterocycl.
Compd. (Engl. Transl.) 2002, 2, 257; (f) Borovlev, I. V.; Demidov, O.
P.; Pozharskii, A. F. Chem. Heterocycl. Compd. (Engl. Transl.) 2002,
8, 968; (g) Borovlev, I. V.; Demidov, O. P.; Pozharskii, A. F. Chem.
Heterocycl. Compd. (Engl. Transl.) 2002, 9, 1084; (h) Borovlev, I. V.;
Demidov, O. P.; Chernyshev, A. V.; Pozharskii, A. F. Russ. Chem.
Bull., Int. Ed. 2002, 1, 139; (i) Borovlev, I. V.; Demidov, O. P.;
Aksenov, A. V.; Pozharskii, A. F. Russ. J. Org. Chem. 2004, 6, 895; (j)
Data for 6-methyl-1,3-diazapyrene-7-carboxylic acid ethyl ester (6e): Mp
153–154 °C (ethyl acetate). 1H NMR (300 MHz, CDCl3): d 1.52 (3H, t,
J = 6.87 Hz, CH3CH2); 3.26 (3H, s, Me); 4.55 (2H, q, J = 6.87 Hz,
CH3CH2); 8.22 (1H, d, J = 9.51 Hz, 9-H); 8.31 (1H, d, J = 9.51 Hz, 5-
H); 8.55 (1H, d, J = 9.51 Hz, 10-H), 8.85 (1H, s, 8-H); 8.93 (1H, d,
J = 9.51 Hz, 4-H); 9.80 (1H, s, 2-H). 13C NMR (50 MHz, CDCl3): d
14.51, 29.77, 61.89, 127.08, 127.17, 127.48, 128.56, 130.21, 132.85,
136.16, 136.36, 138.11, 153.51, 154.49, 156.81, 168.21, 177.22.
m
max(KBr)/cmꢂ1 1720 (C@O); Anal. Calcd for C18H14N2O2: C, 74.47;
H, 4.86; N, 9.65. Found: C, 74.58; H, 4.81; N, 9.58.
Data for 6-methyl-8-phenyl-1,3-diazapyrene (6f): Mp 198–199 °C (ethyl
acetate). Lit.3f mp 198–199 °C. 1H NMR (300 MHz, CDCl3): d 3.19
(3H, s, Me); 7.62 (5H, m, Ph); 8.14 (1H, s, 7-H); 8.32 (1H, d,
J = 9.39 Hz, 5-H); 8.49 (1H, d, J = 9.39 Hz, 9-H); 8.77 (1H, d,

A. V. Aksenov et al. / Tetrahedron Letters 49 (2008) 1808–1811
1811
J = 9.39 Hz, 4-H); 8.98 (1H, d, J = 9.39 Hz, 10-H); 9.76 (1H, s, 2-H).
Anal. Calcd for C21H14N2: C, 85.69; H, 4.79; N, 9.52. Found: C, 85.79;
H, 4.72; N, 9.49.
156.62, 172.33, 203.11. mmax(KBr)/cmꢂ1 1638 (C@O); Anal. Calcd for
C18H14N2O: C, 78.81; H, 5.14; N, 10.21. Found: C, 78.97; H, 5.06; N,
10.13.
1
Data for 6,8-diphenyl-1,3-diazapyrene (6g): Mp 175–176 °C (octane).
Data for 6-phenyl-1,3,7-triazapyrene (8a): Mp 174–176 °C (octane). H
Lit.3f mp 175–176 °C. 1H NMR (300 MHz, CDCl3):
d
7.58–
NMR (300 MHz, CDCl3):d 7.68 (3H, m, 3/4/5-Ph); 7.91 (2H, d,
J = 8.04 Hz, 2/6-Ph); 8.29 (1H, d, J = 9.5 Hz, 10-H); 8.33 (1H, d,
J = 9.13 Hz, 4-H); 8.75 (1H, d, J = 9.5 Hz, 9-H); 8.91 (1H,
d, J = 9.13 Hz, 5-H); 9.86 (1H, s, 8-H); 9.89 (1H, s, 2-H). 13C NMR
(50 MHz, CDCl3): d 118.48, 124.63, 127.42, 127.95, 128.41, 128.69,
130.02, 132.10, 133.12, 133.38, 147.29, 152.94, 153.67, 153.89, 167.23.
Anal. Calcd for C19H11N3: C, 81.12; H, 3.94; N, 14.94. Found: C, 81.27;
H, 3.87; N, 14.86.
Data for 2-methyl-6-phenyl-1,3,7-triazapyrene (8b): Mp 246–248 °C
(octane). 1H NMR (300 MHz, CDCl3): d 3.19 (3H, s, Me); 7.63 (3H, m,
3/4/5-Ph); 7.88 (2H, d, J = 8.06 Hz, 2/6-Ph); 8.18 (1H, d, J = 9.5 Hz,
10-H); 8.24 (1H, d, J = 9.24 Hz, 4-H); 8.60 (1H, d, J = 9.24 Hz, 5-H),
8.76 (1H, d, J = 9.5 Hz, 9-H); 9.69 (1H, s, 8-H). 13C NMR (50 MHz,
CDCl3): d 26.57, 111.95, 118.48, 124.63, 127.42, 127.95, 128.41, 128.69,
130.02, 132.10, 133.12, 133.38, 147.29, 152.94, 153.67, 153.89, 167.17.
Anal. Calcd for C20H13N3: C, 81.34; H, 4.44; N, 14.22. Found: C, 81.44;
H, 4.38; N, 14.18.
Data for 2,6-diphenyl-1,3,7-triazapyrene (8c): Mp 197–199 °C (octane).
1H NMR (300 MHz, CDCl3): d 7.63 (6H, m, 3/4/5-(2)Ph, 3/4/5-(6)Ph);
7.90 (2H, d, J = 8.06 Hz, 2/6-(6)Ph); 8.30 (1H, d, J = 9.5 Hz, 10-H);
8.35 (1H, d, J = 9.18 Hz, 4-H); 8.63 (1H, d, J = 9.18 Hz, 5-H); 8.76 (1H,
d, J = 9.5 Hz, 9-H); 8.84 (2H, d, J = 8.06 Hz, 2/6-(2)Ph); 9.68 (1H, s, 8-
H). 13C NMR (50 MHz, CDCl3): d 117.25, 123.48, 124.63, 127.42,
127.95, 128.41, 128.69, 130.02, 132.10, 133.12, 133.38, 147.29, 152.94,
153.67, 153.89, 167.53. Anal. Calcd for C25H15N3: C, 84.01; H, 4.23; N,
11.76. Found: C, 84.14; H, 4.19; N, 11.67.
7.65 (10H, m, Ph); 8.20 (1H, s, 7-H); 8.26(2H, d, J = 9.14 Hz, 5/9-H);
8.74 (2H, d, J = 9.14 Hz, 4/10-H); 9.81 (1H, s, 2-H). Anal. Calcd
for C26H16N2: C, 87.62; H, 4.52; N, 7.86. Found: C, 87.81; H, 4.46; N,
7.73.
Data for 2,6-dimethyl-1,3-diazapyrene-7-carboxylic acid ethyl ester (6h):
Mp 129–130 °C (ethyl acetate). 1H NMR (300 MHz, CDCl3): d 1.51
(3H, t, J = 6.89 Hz, CH3CH2); 3.12 (3H, s, 6-Me); 3.21 (3H, s, 2-Me);
4.54 (2H, q, J = 6.89 Hz, CH3CH2); 8.21 (1H, d, J = 9.49 Hz, 9-H); 8.32
(1H, d, J = 9.49 Hz, 5-H); 8.55 (1H, d, J = 9.49 Hz, 10-H), 8.84 (1H, s,
8-H); 8.89 (1H, d, J = 9.49 Hz, 4-H). 13C NMR (50 MHz, CDCl3): d
14.52, 24.12, 29.78, 61.77, 127.09, 127.17, 127.46, 128.51, 130.21,
132.81, 136.12, 136.39, 138.15, 153.48, 154.41, 156.78, 168.22, 177.22.
m
max(KBr)/cmꢂ1 1722 (C@O); Anal. Calcd for C19H16N2O2: C, 74.98;
H, 5.30; N, 9.20. Found: C, 75.14; H, 5.21; N, 9.11.
Data for 2,6,8-triphenyl-1,3-diazapyrene (6i): Mp 267–268 °C (octane).
Lit.3f mp 267–268 °C. 1H NMR (300 MHz, CDCl3): d 7.49–7.69 (13H,
m, 6,8-Ph, m- and p-H 2-Ph); 8.09 (1H, s, 7-H); 8.21 (2H, d, J = 9.47 Hz,
5/9-H); 8.59 (2H, d, J = 9.47 Hz, 4/10-H); 8.78 (2H, d, J = 9.31 Hz, o-H
2-Ph). Anal. Calcd for C32H20N2: C, 88.86; H, 4.66; N, 6.48. Found: C,
88.96; H, 4.81; N, 6.35.
Data for 6,8-dimethyl-7-acetyl-1,3-diazapyrene (6j): Mp 165–167 °C
(ethyl acetate). 1H NMR (300 MHz, CDCl3): d 2.84 (3H, s, COMe);
3.18 (6H, s, 6/8-Me); 8.23 (2H, d, J = 9.14 Hz, 5/9-H); 8.54 (2H, d,
J = 9.13 Hz, 4/10-H); 9.81 (1H, s, 2-H). 13C NMR (50 MHz, CDCl3): d
16.31, 31.08, 127.24, 127.61, 128.99, 132.75, 135.81, 139.58, 153.43,