Efficient one-pot synthesis of tetrahydrobenzo[c]xanthene-1,11-dione derivatives under microwave irradiation

Article abstract of DOI:10.1080/00397911.2010.551285

An efficient one-pot condensation of 4-hydroxylcoumarin, aromatic aldehydes, and 5,5-dimethylcyclohexane-1,3-dione has been achieved with molecular iodine as a catalyst via conventional heating and microwave irradiation techniques, and thus a variety of n

Full text of DOI:10.1080/00397911.2010.551285

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Efficient One-Pot Synthesis of
Tetrahydrobenzo[c]xanthene-1,11-dione
Derivatives Under Microwave Irradiation
Xiao-Jun Sun a , Jian-Feng Zhou a & San-Jun Zhi a
a School of Chemistry and Chemical Engineering, Huaiyin Normal
University, Huaian, China
Accepted author version posted online: 27 Oct 2011.Published
online: 26 Mar 2012.
To cite this article: Xiao-Jun Sun , Jian-Feng Zhou & San-Jun Zhi (2012): Efficient One-Pot Synthesis
of Tetrahydrobenzo[c]xanthene-1,11-dione Derivatives Under Microwave Irradiation, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry,
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Synthetic Communications1, 42: 1987–1994, 2012
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2010.551285
EFFICIENT ONE-POT SYNTHESIS OF
TETRAHYDROBENZO[c]XANTHENE-1,11-DIONE
DERIVATIVES UNDER MICROWAVE IRRADIATION
Xiao-Jun Sun, Jian-Feng Zhou, and San-Jun Zhi
School of Chemistry and Chemical Engineering, Huaiyin Normal University,
Huaian, China
GRAPHICAL ABSTRACT
Abstract An efficient one-pot condensation of 4-hydroxylcoumarin, aromatic aldehydes,
and 5,5-dimethylcyclohexane-1,3-dione has been achieved with molecular iodine as a cata-
lyst via conventional heating and microwave irradiation techniques, and thus a variety of
new tetrahydrobenzo[c]xanthene-1,11-dione derivatives were prepared in good yields.
Keywords 4-Hydroxylcoumarin; microwave irradiation; molecular iodine; one-pot
synthesis
INTRODUCTION
Xanthenes and benzoxanthenes have attracted considerable interest because
they possess various biological activities such as antibacterial,[1] antiinflammatory,[2]
and antiviral activities.[3] These structural motifs have also found a niche as antago-
nists for paralyzing the action of zoxazolamine[4] and demonstrate efficacy in photo-
dynamic therapy.[5] In addition, these compounds have been employed as dyes[6] and
pH-sensitive fluorescent materials for visualization of biomolecular assemblies[7] and
utilized in laser technologies.[8] Thus, a broad utility range has made xanthenes prime
synthetic candidates, thereby accentuating the need to develop newer synthetic
routes for scaffold manipulation of xanthene derivatives.
Recently, the use of molecular iodine[9] has received considerable attention as an
inexpensive, nontoxic, readily available catalyst for various organic transformations
Received September 9, 2010.
Address correspondence to Xiao-Jun Sun, School of Chemistry and Chemical Engineering,
Huaiyin Normal University, Huaian 223300, PR China. E-mail: sunxiaojun100@126.com
1987

1988
X.-J. SUN, J.-F. ZHOU, AND S.-J. ZHI
Scheme 1. Synthesis of tetrahydrobenzo[c]xanthene-1,11-dione derivatives under microwave irradiation.
to afford the corresponding products in excellent yields. Microwave activation, as a
nonconventional energy source, has become an important method in organic syn-
thesis.[10] Now, similar reaction has been synthesized using KAl(SO4)2 ꢀ 12H2O as
the catalyst.[11] Here we report a rapid and efficient one-pot method for the
three-component condensation of 4-hydroxylcoumarin, aromatic aldehyde, and
5,5-dimethylcyclohexane-1,3-dione to synthesize tetrahydrobenzo[c]xanthene-1,11-
dione derivatives using molecular iodine as the catalyst under microwave irradiation
(Scheme 1). To the best of our knowledge, this methodology has not been reported
in the literature. These catalysts not only make the synthetic process clean, safe, and
inexpensive but also afford the products in excellent yield.
RESULTS AND DISCUSSION
Structural elucidations of 4a–k were accomplished on the basis of their elemen-
tal analyses and spectral data. As shown in Table 1, we carried out a comparison of
4a–k syntheses using microwave irradiation and conventional heating. Compared to
conventional thermal heating, microwave irradiation greatly reduced the reaction
time from 300 min to 6–8 min. It was obvious that yields increased from 70% to
80%. From these data, we conclude that microwave irradiation is a rapid, efficient,
Table 1. Comparison of conventional and microwave-assisted synthesis of 4a–k
Conventional
Microwave-assisteda
Yieldb (%)
Entry
R
Time (h)
Yieldb (%)
Time (min)
Mp (ꢁC)
4a
4b
4c
4d
4e
4f
H
4-CH3
2.5
2.5
2.5
3
82
75
64
77
78
70
65
63
78
66
61
6
93
219–220
211–213
191–193
228–230
236–238
257–259
220–223
177–179
240–242
181–183
264–266
6
6
7
7
7
8
8
7
7
7
85
78
87
86
83
74
70
84
75
70
4-CH3O
2-Cl
4-Cl
3
2,4-Cl2
4-NO2
4-OH
3
4g
4h
4i
4
4
3,4-(OCH2O)
3,4-(OCH3)2
3-CH3O-4-OH
3
4j
4k
3
3
aMicrowave power: 100 W, temperature: 120 ꢁC.
bYields of the isolated products.

TETRAHYDROBENZO[c]XANTHENE-1,11-DIONE DERIVATIVES
1989
Scheme 2. Tentative mechanism for the formation of tetrahydrobenzo[c]xanthene-1,11-diones.
and environmentally friendly methodology. The results as summarized in Table 1
clearly reveal the scope and generality of the reaction with respect to various substi-
tuted aromatic aldehydes and show that reasonable yields of the products were
achieved after only 6–8 min irradiation by microwave.
A mechanistic rationale portraying the probable sequence of events is given in
Scheme 2.
CONCLUSIONS
In summary, we have described an efficient and mild method for the prep-
aration of tetrahydrobenzo[c]xanthene-1,11-dione derivatives. This process is
efficiently promoted by iodine. The advantages of this method are reduced reaction
times, better yields, mild reaction conditions, easy purification, and economic
viability of the catalyst. We feel that this economically viable procedure will find
practical utility for the one-pot synthesis of novel xanthenes and anthracenes.
EXPERIMENTAL
Melting points were determined in a WRS-1B digital melting-point instrument
and are uncorrected. Infrared (IR) spectra were recorded on a Nicolet Avatar 360
1
FT-IR instrument. H NMR and 13C NMR were measured on a Burke 400-MHz
spectrometer in CDCl3 with tetramethylsilane (TMS) as internal standard. Mass
spectra (MS) were recorded on an LCQ Advantage instrument. Reactions under
microwaves were performed in a CEM Discover1 monomode microwave reactor.
All the reagents are commercially available.
General Procedure for Synthesis of
Tetrahydrobenzo[c]xanthene-1,11-dione Derivatives 4a–k
Conventional method. Iodine (0.2 mmol) in acetic acid (3 ml) was added to a
mixture of aromatic aldehyde (1 mmol), 4-hydroxylcoumarin (1 mmol), and

1990
X.-J. SUN, J.-F. ZHOU, AND S.-J. ZHI
5,5-dimethylcyclohexane-1,3-dione (1.2 mmol). The mixture was stirred at reflux for
the given time (Table 1). The progress of the reaction was monitored by TLC. After
completion of the reaction, the mixture was treated with aqueous Na2S2O3 solution
and stirred at room temperature for 10 min. The precipitate formed was collected by
filtration at the pump, washed with water, and dried. The crude product was recys-
tallized from methanol.
Microwave irradiation method. A 10-mL process vial was charged with
mixture of aromatic aldehyde (1 mmol), 4-hydroxylcoumarin (1 mmol),
a
5,5-dimethylcyclohexane-1,3-dione (1.2 mmol), iodine (0.2 mmol), and acetic acid
(3 mL) and sealed with a cap containing a septum. The loaded vial was then placed
into the cavity of the microwave reactor and heated at 100 W, 120 ꢁC for 6–8 min (as
indicated by thin-layer chromatography, TLC). After completion of the reaction, the
mixture was treated with aqueous Na2S2O3 solution and stirred at room temperature
for 10 min. The formed precipitate was collected by filtration at the pump, washed
with water, and dried. The crude product was recystallized from methanol.
Selected Data
Compound 4a. Mp 219–220 ꢁC; IR (KBr, cmꢂ1): 3062, 2957, 2871, 1714,
1
1663, 1608, 1456, 1365, 1190, 1051, 759. H NMR (400 MHz, CDCl3): d 7.88 (d,
J ¼ 8.0 Hz, 1H), 7.59–7.55 (m, 1H), 7.39–7.24 (m, 6H), 7.17 (m, 1H), 4.98 (s, 1H),
2.74 (d, J ¼ 17.6 Hz, 1H), 2.67 (d, J ¼ 17.6 Hz, 1H), 2.34 (d, J ¼ 16.4 Hz, 1H), 2.27
(d, J ¼ 16.4 Hz, 1H), 1.18 (s, 3H), 1.11 (s, 3H). 13C NMR (400 MHz, CDCl3): d
195.9, 161.9, 160.5, 153.9, 152.6, 142.5, 132.2, 128.6, 128.3, 127.0, 124.2, 122.4,
116.8, 115.2, 113.7, 106.8, 50.8, 40.9, 33.4, 32.3, 29.1, 27.6. MS (ESI): m=z ¼ 373
[M þ H]þ. Anal. calcd. for C24H20O4: C, 77.40; H, 5.41. Found: C, 77.33: H, 5.60.
Compound 4b. Mp 211–213 ꢁC, IR (KBr, cmꢂ1): 3128, 2960, 2869, 1727,
1665, 1614, 1362, 1190, 1055, 759. 1H NMR (400 MHz, CDCl3): d 7.88 (d,
J ¼ 7.6 Hz, 1H), 7.58–7.54 (m, 1H), 7.38–7.28 (m, 4H), 7.07 (d, J ¼ 8.0 Hz, 2H),
4.94 (s, 1H), 2.73 (d, J ¼ 17.6 Hz, 1H), 2.66 (d, J ¼ 17.6 Hz, 1H), 2.33 (d, J ¼ 16.4 Hz,
1H), 2.25 (d, J ¼ 16.4 Hz, 1H), 2.29 (s, 3H), 1.18 (s, 3H), 1.11 (s, 3H). 13C NMR
(400 MHz, CDCl3): d 195.9, 161.8, 160.6, 153.8, 152.6, 139.7, 136.6, 132.1, 129.0,
128.5, 124.2, 122.4, 116.8, 115.3, 113.8, 106.9, 50.8, 40.9, 33.0, 32.3, 32.2, 29.1,
27.6, 21.1. MS (ESI): m=z ¼ 387 [M þ H]þ. Anal. calcd. for C25H22O4: C, 77.70;
H, 5.74. Found: C, 77.53; H, 5.66.
Compound 4c. Mp 191–193 ꢁC; IR (KBr, cmꢂ1): 2960, 1728, 1662, 1609,
1
1508, 1363, 1179, 758. H NMR (400 MHz, CDCl3): d 7.87 (d, J ¼ 7.6 Hz, 1H),
7.58–7.55 (m, 1H), 7.38–7.31 (m, 4H), 6.79 (d, J ¼ 8.8 Hz, 2H), 4.93 (s, 1H), 3.75
(s, 3H), 2.72 (d, J ¼ 17.6 Hz, 1H), 2.66 (d, J ¼ 17.6 Hz, 1H), 2.33 (d, J ¼ 16.4 Hz,
1H), 2.27 (d, J ¼ 16.4 Hz, 1H), 1.18 (s, 3H), 1.11 (s, 3H). 13C NMR (400 MHz,
CDCl3): d 195.9, 161.7, 160.6, 158.6, 153.7, 152.6, 134.9, 132.1, 129.6, 124.4,
124.2, 122.4, 116.9, 115.3, 113.8, 113.7, 107.0, 55.2, 50.8, 40.9, 32.6, 32.3, 29.1,
27.6. MS (ESI): m=z ¼ 425 [M þ Na]þ. Anal. calcd. for C25H22O5: C, 74.61; H,
5.51. Found: C, 74.52; H, 5.65.

TETRAHYDROBENZO[c]XANTHENE-1,11-DIONE DERIVATIVES
1991
Compound 4d. Mp 228–230 ꢁC; IR (KBr, cmꢂ1): 3069, 2958, 2871, 1731,
1667, 1612, 1464, 1360, 1191, 1054, 751. 1H NMR (400 MHz, CDCl3): d 7.89
(d, J ¼ 7.6 Hz, 1H), 7.59–7.53 (m, 2H), 7.38–7.13 (m, 5H), 5.23 (s, 1H), 2.70 (d,
J ¼ 17.6 Hz, 1H), 2.65 (d, J ¼ 17.6 Hz, 1H), 2.32 (d, J ¼ 16.4 Hz, 1H), 2.26
(d, J ¼ 16.4 Hz, 1H), 1.18 (s, 3H), 1.11 (s, 3H). 13C NMR (400 MHz, CDCl3): d
196.0, 162.6, 160.3, 154.6, 152.8, 138.3, 133.8, 133.4, 132.3, 130.3, 128.4, 126.5,
124.2, 122.6, 116.9, 113.4, 113.2, 104.6, 50.7, 40.8, 33.3, 32.1, 29.1, 27.5. MS(ESI):
m=z ¼ 407 [M þ H]þ. Anal. calcd. for C24H19ClO4: C, 70.85; H, 4.71. Found: C,
70.73; H, 4.76.
Compound 4e. Mp 236–238 ꢁC; IR (KBr, cmꢂ1): 3102, 2961, 1722, 1664,
1609, 1490, 1361, 1189, 1056, 762. 1H NMR (400 MHz, CDCl3): d 7.88 (d,
J ¼ 7.6 Hz, 1H), 7.61–7.57 (m, 1H), 7.39–7.21 (m, 6H), 4.95 (s, 1H), 2.73 (d,
J ¼ 17.6 Hz, 1H), 2.67 (d, J ¼ 17.6 Hz, 1H), 2.34 (d, J ¼ 16.4 Hz, 1H), 2.26 (d,
J ¼ 16.4 Hz, 1H), 1.19 (s, 3H), 1.12 (s, 3H). 13C NMR (400 MHz, CDCl3): d 195.8,
162.0, 160.5, 154.0, 152.7, 141.1, 133.0, 132.4, 130.0, 128.8, 128.5, 127.9, 124.3,
122.5, 116.9, 114.9, 113.6, 106.4, 50.7, 40.9, 33.0, 32.3, 29.1, 27.5. MS (ESI): m=
z ¼ 407 [M þ H]þ. Anal. calcd. for C24H19ClO4: C, 70.85; H, 4.71. Found: C,
70.59; H, 4.86.
Compound 4f. Mp 257–259 ꢁC, 90.9%, IR (KBr, cmꢂ1): 2958, 1722, 1667,
1615, 1466, 1361, 1193, 1058, 759. 1H NMR (400 MHz, CDCl3): d 7.88 (d,
J ¼ 7.6 Hz,1H), 7.61–7.58 (m, 1H), 7.48 (d, J ¼ 8.0 Hz, 1H), 7.38 (d, J ¼ 7.6 Hz,
1H), 7.34 (d, J ¼ 7.6 Hz, 1H), 7.28–7.19 (m, 2H), 5.19 (s, 1H), 2.73 (d, J ¼ 17.6 Hz,
1H), 2.67 (d, J ¼ 17.6 Hz, 1H), 2.26 (d, J ¼ 16.4 Hz, 1H), 2.21 (d, J ¼ 16.4 Hz, 1H),
1.18 (s, 3H), 1.12 (s, 3H). 13C NMR (400 MHz, CDCl3): d 196.1, 162.8, 160.3,
154.8, 152.8, 137.0, 134.4, 133.6, 132.5, 129.9, 126.9, 124.3, 122.6, 116.9, 113.3,
112.9, 104.1, 50.7, 40.8, 33.1, 32.2, 32.0, 29.1, 27.5. MS (ESI): m=z ¼ 442 [M þ H]þ.
. Anal. calcd. for C24H18Cl2O4: C, 65.32; H, 4.11. Found: C, 65.23; H, 4.25.
Compound 4g. Mp 220–223 ꢁC; IR (KBr, cmꢂ1): 3075, 2960, 2603, 1722,
1657, 1606, 1517, 1347, 1188, 767. 1H NMR (400 MHz, CDCl3): d 8.19 (d,
J ¼ 8.8 Hz, 1H), 8.12 (d, J ¼ 8.8 Hz, 2H), 7.69–7.34 (m, 5H), 5.05 (s, 1H), 2.76 (d,
J ¼ 18.0 Hz, 1H), 2.71 (d, J ¼ 18.0 Hz, 1H), 2.36 (d, J ¼ 16.4 Hz, 1H), 2.27 (d,
J ¼ 16.4 Hz, 1H), 1.19 (s, 3H), 1.13 (s, 3H). 13C NMR (400 MHz, CDCl3): d 195.8,
162.6, 160.4, 154.5, 152.8, 149.7, 146.9, 143.4, 132.8, 129.7, 127.6, 124.5, 123.8,
122.6, 116.8, 114.2, 113.3, 105.4, 50.6, 40.9, 33.8, 32.4, 29.1, 27.5. MS (ESI): m=
z ¼ 418 [M þ H]þ. Anal. calcd. for C24H19NO6: C, 69.06; H, 4.59; N, 3.36. Found:
C, 69.53; H, 4.42; N, 3.30.
Compound 4h. Mp 177–179 ꢁC, IR (KBr, cmꢂ1): 3639, 3379, 2961, 1695,
1
1661, 1613, 1513, 1364, 1191, 1055, 765. H NMR (400 MHz, CDCl3): d 7.87 (d,
J ¼ 7.6 Hz, 1H), 7.59–7.56 (m, 1H), 7.38–7.21 (m, 4H), 6.67 (d, J ¼ 8.8 Hz, 2H),
4.91 (s, 1H), 3.51 (s, 1H), 2.73 (d, J ¼ 17.6 Hz, 1H), 2.66 (d, J ¼ 17.6 Hz, 1H), 2.34
(d, J ¼ 16.4 Hz, 1H), 2.28 (d, J ¼ 16.4 Hz, 1H), 1.18 (s, 3H), 1.11 (s, 3H). 13C
NMR (400 MHz, CDCl3): d 196.3, 161.8, 160.7, 154.7, 153.8, 152.6, 132.1, 129.8,
124.2, 122.4, 116.9, 115.4, 115.3, 113.8, 107.0, 50.8, 40.9, 32.6, 32.4, 29.1, 27.6. MS
(ESI): m=z ¼ 411 [M þ Na]þ. Anal. calcd. for C24H20O5: C, 74.21; H, 5.19. Found:
C, 74.32; H, 5.05.

1992
X.-J. SUN, J.-F. ZHOU, AND S.-J. ZHI
Compound 4i. Mp 240–242 ꢁC, IR (KBr, cmꢂ1): 3067, 2958, 2876, 1724,
1
1665, 1607, 1486, 1363, 1186, 1048, 760. H NMR (400 MHz, CDCl3): d 7.87 (d,
J ¼ 7.6 Hz, 1H), 7.59–7.56 (m, 1H), 7.37 (d, J ¼ 8.0 Hz, 1H), 7.33 (d, J ¼ 8.0 Hz,
1H), 6.88–6.68 (m, 3H), 5.88 (s, 2H), 4.89 (s, 1H), 2.72 (d, J ¼ 17.6 Hz, 1H), 2.65
(d, J ¼ 17.6 Hz, 1H), 2.34 (d, J ¼ 16.4 Hz, 1H), 2.29 (d, J ¼ 16.4 Hz, 1H), 1.18 (s,
3H), 1.12 (s, 3H). 13C NMR (400 MHz, CDCl3): d 196.0, 161.8, 160.6, 153.8,
152.6, 147.6, 146.6, 136.6, 132.2, 124.2, 122.4, 121.9, 116.9, 115.2, 113.7, 109.3,
108.1, 106.8, 100.9, 50.8, 40.9, 33.0, 32.3, 29.0, 27.7. MS (ESI): m=z ¼ 439 [M þ Na]þ.
Anal. calcd. for C25H20O6: C, 72.11; H, 4.84. Found C, 72.03, H, 5.01.
Compound 4j. Mp 181–183 ꢁC; IR (KBr, cmꢂ1): 2954, 2836, 1723, 1662,
1608, 1513, 1362, 1190, 1056, 762. 1H NMR (400 MHz, CDCl3): d 7.83 (d,
J ¼ 7.6 Hz, 1H), 7.59–7.55 (m, 1H), 7.37 (d, J ¼ 8.0 Hz, 1H), 7.33 (d, J ¼ 8.0 Hz,
1H), 7.05 (s, 1H), 6.82–6.75 (m, 2H), 4.93 (s, 1H), 3.89 (s, 3H), 3.81 (s, 3H), 2.73
(d, J ¼ 17.6 Hz, 1H), 2.67 (d, J ¼ 17.6 Hz, 1H), 2.35 (d, J ¼ 16.4 Hz, 1H), 2.29 (d,
J ¼ 16.4 Hz, 1H), 1.19 (s, 3H), 1.13 (s, 3H). 13C NMR (400 MHz, CDCl3): d 196.0,
161.8, 160.7, 153.7, 152.6, 148.8, 148.2, 135.4, 132.1, 124.2, 122.4, 120.3, 116.9,
115.3, 113.8, 112.9, 111.2, 106.9, 56.0, 55.8, 50.8, 40.9, 32.8, 32.3, 29.2, 27.5. MS
(ESI): m=z ¼ 455 [M þ Na]þ. Anal. calcd. for C26H24O6: C, 72.21; H, 5.59. Found:
C, 72.12; H, 5.61.
Compound 4k. Mp 264–266 ꢁC; IR (KBr, cmꢂ1): 3434, 3130, 2949, 1713,
1
1665, 1606, 1514, 1363, 1183, 1036, 774. H NMR (400 MHz, CDCl3): d 7.87 (d,
J ¼ 7.6 Hz, 1H), 7.59–7.55 (m, 1H), 7.37 (d, J ¼ 8.0 Hz, 1H), 7.34 (d, J ¼ 8.0 Hz,
1H), 7.14 (s, 1H), 6.77–6.63 (m, 2H), 5.52 (s, 1H), 4.90 (s, 1H), 3.93 (s, 3H), 2.73
(d, J ¼ 17.6 Hz, 1H), 2.66 (d, J ¼ 17.6 Hz, 1H), 2.34 (d, J ¼ 16.4 Hz, 1H), 2.29 (d,
J ¼ 16.4 Hz, 1H), 1.19 (s, 3H), 1.13 (s, 3H). 13C NMR (400 MHz, CDCl3): d 196.1,
161.8, 160.7, 153.7, 152.6, 146.1, 144.7, 134.8, 132.1, 124.2, 122.4, 120.3, 116.9,
115.3, 114.1, 113.8, 112.6, 107.0, 56.0, 50.8, 40.9, 32.9, 32.3, 29.2, 27.5. MS (ESI):
m=z ¼ 441 [M þ Na]þ. Anal. calcd. for C25H22O6: C, 71.76; H, 5.30. Found: C,
71.55; H, 5.46.
ACKNOWLEDGMENT
We are grateful to the Jiangsu Key Laboratory of Chemistry of Low-
Dimensional Materials.
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