1348
D. Patoilo, A. Silva, D. Pinto, A. Tomé and J. Cavaleiro
Vol 44
respectively). Electron impact (EI, 70 eV) MS were recorded on
VG AutoSpec Q and M spectrometers. Elemental analyses were
obtained with a CHNS 932 Leco analyser (University of Aveiro)
or with a Carlo Erba 1108 analyzer (University of Vigo).
Preparative thin-layer chromatography was performed with
Merck silica gel 60 DGF254. Column chromatography was
performed with Merck silica gel 60, 70-230 mesh. All other
chemicals and solvents used were obtained from commercial
sources and used as received or dried using standard procedures.
Microwave assisted synthesis was carried out in an Ethos
SYNTH Microwave (Milestone Inc.) apparatus.
5-Hydroxy-2-[3-(4-methoxyphenyl)-1,2,3,4-tetrahydro-
naphth-2-yl]chromone (3c). Yield: 376 mg (63%); mp 164-
166 ºC (from cyclohexane/dichloromethane). 1H NMR: ꢀ =
3.12-3.24 (m, 4 H, H-1', H-2', 2 x H-4'), 3.30-3.40 (m, 2 H, H-
3', H-1'), 3.73 (s, 3 H, 4''-OCH3), 5.99 (s, 1 H, H-3), 6.73 (dd,
1 H, J = 8.2 and 0.8 Hz, H-6), 6.75 (d, 2 H, J = 8.7 Hz, H-
3'',5''), 6.82 (dd, 1 H, J = 8.4 and 0.8 Hz, H-8), 7.10 (d, 2 H, J
= 8.7 Hz, H-2'',6''), 7.13-7.21 (m, 4 H, H-5',6',7',8'), 7.47 (dd, 1
H, J = 8.2 and 8.4 Hz, H-7), 12.43 (s, 1 H, 5-OH). 13C NMR: ꢀ
= 34.6 (C-1'), 38.0 (C-4'), 43.1 (C-3'), 46.7 (C-2'), 106.6 (C-8),
109.3 (C-3), 110.5 (C-10), 111.1 (C-6), 114.1 (C-3'',5''), 126.2
and 126.4 (C-6' and C-7'), 128.1 (C-2'',6''), 128.6 and 129.0
(C-5' and C-8'), 134.0 and 134.5 (C-9' and C-10'), 135.0 (C-7),
135.5 (C-1''), 156.6 (C-9), 158.3 (C-4''), 160.6 (C-5), 171.9 (C-
2), 183.3 (C-4). EI-MS: m/z relative intensity 398 (M+•, 100),
293 (3), 277 (2), 223 (24), 137 (3), 121 (85), 115 (13), 104 (9),
91 (2). Anal. calcd. for C26H22O4: C 78.37, H 5.57. Found C
78.25, H 5.56%.
5-Hydroxy-2-[3-(4-nitrophenyl)-1,2,3,4-tetrahydronaphth-
2-yl]chromone (3d). Yield: 490 mg (79%); mp 195-197 ºC
(from cyclohexane/dichloromethane). 1H NMR: ꢀ = 3.18
(dd, 1 H, J = 12.2 and 5.5 Hz, H-1'), 3.27 (dd, 1 H, J = 12.2
and 3.4 Hz, H-1'), 3.10-3.41 (m, 3 H, 2 x H-4', H-2'), 3.52-
3.62 (m, 1 H, H-3'), 6.01 (s, 1 H, H-3), 6.74 (dd, 1 H, J =
8.3 and 0.6 Hz, H-6), 6.80 (d br, 1 H, J = 8.2 Hz, H-8), 7.13-
7.26 (m, 4 H, H-5',6',7',8'), 7.39 (d, 2 H, J = 8.7 Hz, H-
2'',6''), 7.47 (dd, 1 H, J = 8.3 and 8.2 Hz, H-7), 8.11 (d, 2 H,
J = 8.7 Hz, H-3'',5''), 12.30 (s, 1 H, 5-OH). 13C NMR: ꢀ =
34.4 (C-1'), 37.4 (C-4'), 44.0 (C-3'), 46.0 (C-2'), 106.4 (C-
8), 109.3 (C-3), 110.4 (C-10), 111.6 (C-6), 124.1 (C-3'',5''),
126.7 (C-6',7'), 128.1 (C-2'',6''), 128.3 and 128.7 (C-5' and
C-8'), 133.5 (C-10'), 134.3 (C-9'), 135.3 (C-7), 147.0 (C-4''),
150.2 (C-1''), 156.4 (C-9), 160.7 (C-5), 170.5 (C-2), 183.0
(C-4). EI-MS m/z relative intensity 413 (M+• , 100), 277
(25), 192 (10), 137 (14), 115 (9), 104 (44), 78 (7). EI-
HRMS: calcd. for C25H19NO5 413.1263; Found 413.1269.
2-(3-Phenyl-1,2,3,4-tetrahydronaphth-2-yl)chromone (3e).
Yield: 467 mg (89%); mp 141-143 ºC (from cyclohexane/
dichloromethane) (lit. mp [39]: 143-145 ºC).
2-[3-(4-Chlorophenyl)-1,2,3,4-tetrahydronaphth-2-yl]-
chromone (3f). Yield: 531 mg (92%); mp 163-165 ºC (from
cyclohexane/dichloromethane) (lit. mp [39]: 162-164 ºC).
2-[3-(4-Methoxyphenyl)-1,2,3,4-tetrahydronaphth-2-yl]-
chromone (3g). Yield: 354 mg (62%); mp 169-171 ºC (from
cyclohexane/dichloromethane) (lit. mp [39]: 169-171 ºC).
2-[3-(4-Nitrophenyl)-1,2,3,4-tetrahydronaphth-2-yl]-
chromone (3h). Yield: 477 mg (80%); mp 195-197 ºC (from
cyclohexane/dichloromethane). 1H NMR: ꢀ = 3.14-3.37 (m, 5 H,
2 x H-1', H-2', 2 x H-4'), 3.54-3.59 (m, 1 H, H-3'), 6.09 (s, 1 H,
H-3), 7.13-7.24 (m, 4 H, H-5',6',7',8'), 7.33-7.36 (m, 1 H, H-6),
7.36 (dd, 1 H, J = 8.1 and 0.7 Hz, H-8), 7.39 (d, 2 H, J = 9.0 Hz,
H-2'',6''), 7.63 (dt, 1 H, J = 8.1 and 1.6 Hz, H-7), 8.06-8.09 (m, 1
H, H-5), 8.08 (d, 2 H, J = 9.0 Hz, H-3'',5''). 13C NMR: ꢀ = 34.4
(C-4'), 37.5 (C-1'), 44.0 (C-3'), 45.9 (C-2'), 110.8 (C-3), 117.4
(C-8), 123.6 (C-10), 124.0 (C-3'',5''), 125.2 (C-6), 125.7 (C-5),
126.6 (C-5',8'), 128.2 (C-2'',6''), 128.6 and 128.7 (C-6' and C-7'),
133.7 (C-7), 133.8 (C-10'), 134.4 (C-9'), 146.9 (C-4''), 150.5 (C-
1''), 156.1 (C-9), 169.1 (C-2), 177.8 (C-4). EI-MS: m/z relative
intensity 397 (M+•, 3), 281 (13), 261 (100), 238 (4), 192 (9), 160
(5), 141 (6), 121 (13), 116 (21), 104 (43), 92 (3), 78 (7). Anal.
calcd. for C25H19NO4: C 75.55, H 4.82, N 3.52. Found C 75.42,
H 4.87, N 3.51%.
2-Styrylchromones 1a-h. Prepared as described in the
literature [57].
1,3-Dihydrobenzo[c]thiophene 2,2-Dioxide. Prepared according
to literature procedure [40].
Synthesis of 2-(3-aryl-1,2,3,4-tetrahydronaphth-2-yl)chro-
mones 3a-h. A solution of an appropriate 2-styrylchromone 1a-
h (1.5 mmol) and 1,3-dihydrobenzo[c]thiophene 2,2-dioxide
(336 mg, 2 mmol) in 1,2,4-trichlorobenzene (10 mL), under
nitrogen atmosphere, was refluxed for 10 h. Then more 1,3-
dihydrobenzo[c]thiophene 2,2-dioxide (84 mg, 0.5 mmol) was
added and the reflux maintained for 14 hours. After cooling to
room temperature, the reaction mixture was purified by column
chromatography on silica gel. Elution with light petroleum
removed 1,2,4-trichlorobenzene, while elution with a 7:3 mixture
of dichloromethane:light petroleum afforded the cycloadducts 2-
(3-aryl-1,2,3,4-tetrahydronaphth-2-yl)]chromones 3a-h in good
yields.
5-Hydroxy-2-(3-phenyl-1,2,3,4-tetrahydronaphth-2-yl)-
chromone (3a). Yield: 387 mg (70%); mp 138-140 ºC (from
cyclohexane/dichloromethane). 1H NMR: ꢀ = 3.22-3.44 (m, 6 H,
2 x H-1', H-2', H-3', 2 x H-4'), 6.06 (s, 1 H, H-3), 6.78 (br d, 1 H,
J 8.3 Hz, H-6), 6.88 (br d, 1 H, J = 8.3 Hz, H-8), 7.18-7.32 (m, 9
H, H-5',6',7',8', 3'-C6H5), 7.52 (t, 1 H, J = 8.3 Hz, H-7), 12.49 (s,
1H, 5-OH). 13C NMR: ꢀ = 34.5 (C-1'), 37.8 (C-4'), 44.0 (C-3'),
46.4 (C-2'), 106.6 (C-8), 109.2 (C-3), 110.4 (C-10), 111.1 (C-6),
126.2 and 126.4 (C-6' and C-7'), 127.0 (C-4''), 127.1 (C-3'',5''),
128.6 (C-5',8'), 128.7 (C-2'',6''), 133.9 (C-9'), 135.0 (C-7), 135.3
(C-10'), 142.5 (C-1''), 156.5 (C-9), 160.6 (C-5), 171.7 (C-2),
183.2 (C-4). EI-MS: m/z relative intensity 368 (M+•, 100), 277
(37), 263 (13), 252 (12), 193 (24), 178 (13), 149 (5), 137 (16),
115 (23), 104 (27), 91 (21), 71 (12), 57 (15). Anal. calcd. for
C25H20O3: C 81.14, H 5.48. Found C 81.50, H 5.47%.
2-[3-(4-Chlorophenyl)-1,2,3,4-tetrahydronaphth-2-yl]-5-
hydroxychromone (3b). Yield: 435 mg (72%); mp 118-120 ºC
1
(from cyclohexane/dichloromethane). H NMR: ꢀ = 3.18-3.30
(m, 5 H, 2 x H-1', H-2', 2 x H-4'), 3.31-3.44 (m, 1 H, H-3'), 5.99
(s, 1 H, H-3), 6.73 (dd, 1 H, J = 8.3 and 0.6 Hz, H-6), 6.80 (dd, 1
H, J = 8.4 and 0.6 Hz, H-8), 7.11-7.25 (m, 4 H, H-5',6',7',8'),
7.12 (d, 2 H, J = 8.4 Hz, H-2'',6''), 7.19 (d, 2 H, J = 8.4 Hz, H-
3'',5''), 7.46 (dd, 1 H, J = 8.3 and 8.4 Hz, H-7), 12.39 (s, 1 H, 5-
OH). 13C NMR: ꢀ = 34.5 (C-1'), 37.7 (C-4'), 43.4 (C-3'), 46.2
(C-2'), 106.5 (C-8), 109.2 (C-3), 110.4 (C-10), 111.3 (C-6),
126.4 and 126.5 (C-6' and C-7'), 128.5 (C-2'',6''), 128.58 and
128.64 (C-5' and C-8'), 128.9 (C-3'',5''), 132.6 (C-4''), 133.7 (C-
10'), 134.9 (C-9'), 135.1 (C-7), 141.0 (C-1''), 156.4 (C-9), 160.6
(C-5), 171.2 (C-2), 183.1 (C-4). EI-MS: m/z relative intensity
402 (M+•, 100), 368 (2), 297 (6), 286 (7), 277 (40), 263 (7), 227
(23), 202 (7), 192 (19), 176 (9), 165 (5), 149 (10), 137 (20), 125
(20), 115 (22), 104 (45), 91 (8), 78 (12). EI-HRMS: calcd. for
C25H19ClO3 402.1023; found 402.1032.