November 2011 Molecular Iodine-Catalyzed One-Pot Synthesis of Tetrahydrobenzo[a]xanthene-
11-One and Diazabenzo[a]anthracene-9,11-Dione Derivatives Under Microwave Irradiation
1349
Table 3
I2 catalyzed condensation of aldehydes, b-naphthol and cyclic 1,3-dicarbonyl compounds to give 5 and 6 under microwave irradiation.a
Entry
R1
Time (min)
Yieldb (%)
Mp (observed/reportedref)(ꢀC)
5a
5b
5c
5d
5e
5f
5g
5h
5i
C6H5
6
6
7
8
6
6
6
6
8
6
6
8
8
9
8
9
8
9
8
8
92
93
80
94
92
89
82
90
75
80
94
75
78
71
72
74
75
72
70
76
152–154/151–153 [12]
173–175/176–178 [12]
201–203/204–205 [12]
173–174/179–180 [12]
177–179/180–182 [12]
175–176/178–180 [12]
169–171/168–170 [12]
179–181/178–180 [12]
221–223/223–225 [12]
230–232/Not rep.
4-MeC6H4
4-OMeC6H4
2-ClC6H4
4-ClC6H4
2,4-Cl2C6H4
3-NO2C6H4
4-NO2C6H4
4-OHC6H4
2-FC6H4
5j
5k
6a
6b
6c
6d
6e
6f
6g
6h
6i
3,4-(OCH2O)C6H3
C6H5
203–205/Not rep.
227–229/226–228 [12]
199–201/196–198 [12]
274–275/270–272 [12]
221–223/222–224 [12]
271–273/270–272 [12]
285–287/288–290 [12]
283–285/288–290 [12]
287–289/Not rep.
4-MeC6H4
4-ClC6H4
2,4-Cl2C6H4
2-ClC6H4
2-NO2C6H4
4-NO2C6H4
2-FC6H4
3,4-(OCH2O)C6H3
204–206/Not rep.
a Reaction condition: 1 (1 mmol), 2 (1 mmol), 3 (1.2 mmol), iodine (20 mol%), under microwave irradiation.
b Isolated yield.
monomode microwave reactor. All the reagents are commer-
cially available.
138.9, 131.5, 131.4, 128.8, 128.4, 126.9, 124.9, 123.7, 121.8,
117.7, 117.1, 114.3, 108.9, 107.9, 100.7, 50.7, 41.4, 34.3, 32.3,
29.2, 27.3. IR (KBr, cmꢁ1): 3132, 2959, 2878, 1645, 1399,
1226, 1174, 1034, 823. MS(ESI): m/z ¼ 399 [MþH]þ. Anal.
Calcd for C26H22O4: C 78.37, H 5.57; found C 78.53, H 5.62.
Compound 6h: 1H NMR(400 MHz, CDCl3): d 7.89–7.81
(m, 2H), 7.69 (d, J ¼ 7.8 Hz, 1H), 7.45–7.41 (m, 3H), 7.09–
7.04 (m, 2H), 6.66–6.58 (m, 2H), 6.02 (s, 1H), 3.64 (s, 3H),
3.41 (s, 3H). 13C NMR (400 MHz, CDCl3): d 164.9, 153.6,
153.3, 149.9, 147.5, 132.1, 131.8, 130.7, 129.8, 128.4, 128.3,
127.9, 125.8, 123.8, 121.6, 119.5, 117.2, 115.8, 90.9, 29.4,
29.2, 28.7. IR (KBr, cmꢁ1): 3151, 2956, 1710, 1625, 1488,
1231, 1176. MS(ESI): m/z ¼ 389 [MþH]þ. Anal. Calcd for
C23H17FN2O3: C 71.13, H 4.41, N 7.21; found C 71.36, H
4.65, N 7.05.
General procedure for synthesis of 12-aryl-8,9,10,12-tet-
rahydrobenzo[a]xanthene-11-one (5) and 8,10-dimethyl-12-
aryl-8,12-dihydro-7-oxa-8,10-diazabenzo[a]anthracene-9,11-
dione (6). A 10-mL process vial was charged with a mixture
of the aromatic aldehyde (1 mmol), b-naphthol (1 mmol),
cyclic-1,3-dicarbonyl compound (1.2 mmol), iodine (0.2
mmol), and acetic acid (3 mL) and sealed with a cap contain-
ing a septum. The loaded vial was then placed into the cavity
of the microwave reactor and heated at 100 W, 120ꢀC for 6–9
min (as indicated by thin-layer chromatography). After com-
pletion of the reaction, the mixture was treated with aq
Na2S2O3 solution and stirred at room temperature for 10 min.
The precipitate formed was collected by vacuum filtration,
washed with water, and dried. The crude product was recystal-
lized from methanol.
Spectral data of some representative products are given
below. Compound 5j: 1H NMR(400 MHz, CDCl3): d 7.81–
7.77 (m, 2H), 7.69 (d, J ¼ 8.0 Hz, 1H), 7.44–7.28 (m, 3H),
7.04–7.01 (m, 2H), 6.64–6.61 (m, 2H), 5.79 (s, 1H), 2.63 (s,
1H), 2.44 (d, J ¼ 16.4 Hz, 1H), 2.37 (d, J ¼ 16.4 Hz, 1H),
1.17 (s, 3H), 1.02 (s, 3H). 13C NMR (400 MHz, CDCl3): d
166.8, 152.9, 147.9, 132.7, 131.6, 131.2, 129.1, 128.7, 128.2,
127.9, 127.5, 125.3, 123.5, 121.5, 118.9, 117.5, 116.6, 50.3,
41.6, 32.4, 29.0, 28.0, 27.2. IR (KBr, cmꢁ1): 3196, 2957,
2891, 1628, 1380, 1229, 1180, 1032, 811. MS(ESI): m/z ¼
373 [MþH]þ. Anal. Calcd for C25H21FO2: C 80.62, H 5.68;
found C 80.55, H 5.82.
Scheme 2
1
Compound 5k: H NMR (400 MHz, CDCl3): d 7.99 (d, J ¼
8.4 Hz, 1H), 7.81–7.76 (m, 2H), 7.49–7.28 (m, 3H), 6.88–6.80
(m, 2H), 6.63 (d, J ¼ 8.0 Hz, 1H), 5.81 (s, 2H), 5.65(s, 1H),
2.58 (s, 2H), 2.28 (s, 2H), 1.14 (s, 3H), 1.02 (s, 3H). 13C
NMR (400 MHz, CDCl3): d 196.8, 163.7, 147.7, 147.5, 145.8,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet