1352
S. Kumar, S. Saravanan, P. Reuben, and A. Kumar
Vol. 42
of 2-3 min. The mixture was stirred at the ambient temperature
for 12 h, and then treated with ice-cold water. The organic layer
H, J = 8.3 Hz), 7.29 (dd, 1 H, J = 5.8 and 0.9 Hz), 7.53 (d, 1 H, J
13
= 5.4 Hz), 9.55 (d, 1 H, J = 0.4 Hz); C NMR (CDCl ): δ 186.0
3
was separated, washed with water, dried (Na SO ), and concen-
(CHO), 158.4, 156.2, 138.5, 138.0, 129.5, 126.9, 125.2, 122.3,
106.5, 55.4, 28.7, 23.5, 22.7, 22.2.
2
4
trated under reduced pressure to afford a solid. Trituration of the
solid with hexane produced 0.066 g (90%) of 23 as greenish yel-
Anal. Calcd. for C H O S: C, 70.58; H, 5.88%; Found: C,
70.44; H, 5.88.
16 12
2
1
low solid, mp 148-150 °C. H NMR (CDCl ) δ 7.13 (d, 1 H, J =
3
3.6), 7.17 (d, 1 H, J = 3 Hz),7.26-7.31 (m, 1 H), 7.32-7.38(m, 2
H), 7.43-7.48 (m, 1 H) , 7.65-7.70 (m, 1 H), 7.80 (d, 1 H, J = 3.4
7-Methoxy-8,9,10,11-tetrahydrophenanthro[4,3-b]thiophene
(22).
Hz), 7.89 (d, 1 H, J = 2.6 Hz), 9.12(d, 1 H, J = 4.0 Hz).
+
A mixture containing the aldehyde 20a (1.24 g, 4.8 mmol),
trimethylsulfonium iodide (1.03 g, 5.0 mmol), and powdered
KOH (0.44 g, 7.8 mmol) in acetonitrile (40 mL) was stirred at 60-
65 °C for 13 h. The usual workup of the reaction mixture as
described above for the epoxide 19b gave 1.28 g (100%) of suffi-
Anal. Calcd. for C H OS [M ]: 250.0452. Found (EI): [M+],
16 10
250.0458.
Phenanthro[3,4-b]thiophene-6,7-dione (24).
To a solution of 23 (0.06 g, 0.24 mmol) in 16% CH Cl -ben-
2
2
1
zene (10 mL) was added 0.17 M KH PO (5 mL), 1 drop of ado-
ciently pure 20b as an oil [ H NMR (CDCl ): δ 1.65-1.90 (m, 4
2
4
3
gen-64 and Fremy’s salt (0.194 g, 0.72 mmol), successively. The
mixture was stirred vigorously for 3 h. The dark organic layer
was separated, washed with water and dried over anhydrous
H), 2.50-2.66 (m, 2 H), 2.68-2.77 (m, 2 H), 2.96 (dd, 1 H, J = 2.6
Hz and 5.2 Hz), 3.08 (dd, 1 H, J = 4 Hz and 5 Hz), 3.60 (dd, 1 H,
J = 2.6 Hz and 3.6 Hz), 6.75 (d, 1 H, J = 8.2 Hz), 6.83 (d, 1 H, J
= 5.5 Hz), 7.17 (d, 1 H, J = 8.2 Hz), 7.27 (d, 1 H, J = 5.5 Hz)].
Na SO , and concentrated in vacuo. The residue was triturated
2
4
with EtOH, and the resulting brick red solid was filtered to afford
0.048 g (75%) of pure dione 24, mp 210-212 °C; H NMR
A solution of BF .Et O (5.3 mL) in 20 mL of Et O was added
dropwise under argon over 5 min to a stirred solution of the 20b
3 2 2
1
(CDCl ) δ 7.48 (dt, 1 H, J = 0.8 and 6.8 Hz), 7.69 (d, 1 H, J = 5.8
(1.24 g, 4.33 mmol) in anhydrous Et O (50 mL) at 0 °C. The
3
2
Hz), 7.74 (dt, 1 H, J = 1.5 and 8.0 Hz), 7.92 (d, 1H, J = 8.4 Hz),
8.03 (d, 1 H, J = 5.7 Hz), 8.10 (d, 1 H, J = 8.4 Hz), 8.15 (dd, 1 H,
J = 1.4 and 7.7 Hz), 8.20 (d, 1 H, J = 8.0 Hz).
mixture was stirred at the ambient temperature for an additional
10 h. Isolation of the crude product as described for 21 gave an
oil which was chromatographed over a short column of dry col-
umn grade silica gel. Elution of the column with petroleum ether
(60-80 °C) afforded 233 mg (20%) of 22 as colorless plates, mp
+
+
Anal. Calcd. for C H O S (M ): 264.0245. Found (EI): [M ],
16
8 2
264.0233.
1
110-112 °C. H NMR (CDCl ): δ 1.86-1.92 (m, 2 H), 1.98-2.05
3
trans-6,7-Dihydroxy-6,7-dihydrophenanthro[3,4-b]thiophene (5).
A solution containing 24 (0.04 g, 0.15 mmol) and NaBH
(m, 2 H), 2.84-2.89 (m, 2 H), 3.42-3.47 (m, 2 H), 3.96 (s, 3 H),
7.15 (s, 1 H), 7.49 (d, 1 H, J = 5.5 Hz), 7.52 (d, 1 H, J = 5.5 Hz),
4
13
(0.46 g, 12.8 mmol) in ethanol (20 mL) was stirred while a
7.66 (d, 1 H, J = 8.5 Hz), 7.80 (d, 1 H, J = 8.5 Hz); C NMR
stream of O was gradually passed through the solution. After 12
(CDCl ): δ 155.3, 136.7, 135.2, 133.8, 131.4, 127.6, 125.5,
2
3
h of stirring, the resulting nearly colorless solution was concen-
trated in vacuo to 5-6 mL, diluted with water (15 mL), and then
extracted with EtOAc (2 X 25 mL). The combined EtOAc layer
124.9, 124.4, 124.2, 121.7, 104.3, 55.3, 30.1, 24.5, 23.4, 21.8.
Anal. Calcd. for C H OS: C, 76.11; H, 5.97%; Found: C,
17 16
76.28; H, 5.95.
was washed with brine, and dried ( Na SO ). The concentration
of the solvent under reduced pressure, and the trituration of the
2
4
7-Methoxyphenanthro[4,3-b]thiophene (17).
7-Methoxy-8,9,10,11-tetrahydrophenanthro[4,3-b]thiophene
22 (140 mg, 0.53 mmol) was dehydrogenated with DDQ (280
mg, 1.23 mmol) in anhydrous benzene (30 mL) as described for
14 to afford 126 mg (91%) of 17 as colorless crystals, mp 130-
residual solid with peroxide-free diethyl ether gave 10 mg (27%)
1
of 5 as a pale yellow solid, mp 124-127 °C. H NMR (DMSO-d
6
+ MeOH-d ) δ 5.67 (d, 1 H, J = 4.14 Hz), 5.72 (d, 1 H, J =
4
6,7
6,7
4.14 Hz), 7.35-7.45 (m, 2 H), 7.62-7.69 (m, 2 H), 7.86-8.02 (m, 4
1
1
132 °C. H NMR (CDCl ): δ 4.16 (s, 3 H), 7.20 (s, 1 H), 7.55-
H). H NMR (CDCl + MeOH-d ) δ 4.72 (d, 1 H, J
= 11.0
3
3
4
6,7
7.65 (m, 2 H), 7.68-7.79 (m, 1 H, 7.80-7.95 (m, 2 H), 8.03 (d, 1
Hz), 5.72 (d, 1 H, J = 11.0 Hz), 7.39-7.51 (m, 2 H), 7.60 (d, 1
6,7
H, J = 8.3 Hz), 8.55 (d, 1 H, J = 8.3 Hz), 9.22 (d, 1 H, J = 8.5 Hz);
H, J = 7.0), 7.67-7.77 (m, 2 H), 7.88-8.02 (m, 3 H).
13
+
+
C NMR (CDCl ): δ 155.1, 141.3, 132.7, 129.8, 127.4, 127.0,
Anal. Calcd for C H O S [M ]: 268.0553. Found (EI): [M ],
3
16 12
2
126.7, 125.7, 125.6, 125.2, 125.1, 123.0, 122.3, 103.4, 55.6.
268.0556.
Anal. Calcd. for C H OS.1/20CH Cl : C, 76.11; H, 4.50%;
17 12
2
2
2-(4-Methoxy-5,6,7,8-tetrahydro-1-naphthyl)thiophene-3-car-
boxaldehyde (20a).
+
Found: C, 76.16; H, 4.88. Anal. Calcd. for C
H OS [M ]:
17 12
+
264.0603. Found (EI): [M ], 264.0651.
In an oven-dried flask flushed with argon was added 18 (2.25
g, 10 mmol), boronic acid 11b (1.38 g, 10 mmol), KF (1.92 g, 40
mmol), Pd (dba) (48 mg, 0.052 mmol) and THF (15 mL), suc-
7-Hydroxyphenanthro[4,3-b]thiophene (25).
Demethylation of 17 (0.1 g, 0.38 mmol) in anhydrous CH Cl
2
2
2
3
(20 mL) with 1 M solution of BBr (1.1 mL, 1.1 mmol) in CH Cl
cessively. While stirring the mixture under argon, a solution of
P(t-Bu) (0.5 mL, 0.2 M) in CH Cl , and the resulting reaction
mixture with green suspension was stirred for additional 20 h at
rt. The mixture was processed according to the procedure
described for 19a to produce 1.51 g (57%) of 20a as a colorless
3
2
2
was carried out under argon as described in the preparation of 23.
The isolated product was purified by trituration with hexane to
give 0.082 g (80%) of 25 as light yellow crystals, mp 187-190 °C.
3
2
2
1
H NMR (CDCl ): δ 2.70 (bs, 1 H, exchangeable with D O), 7.25
3
2
(s, 1 H), 7.52 (pseudo s, 2 H), 7.64-7.71 (m, 2 H), 7.92 (d, 1 H, J =
8.4 Hz), 8.51 (d, 1 H, J = 8.0 Hz), 9.14 (d, 1 H, J = 8.3 Hz).
crystalline solid. A small sample of the solid was recrystallized
1
from hexane to produce colorless crystals, mp 110-111 °C.
H
+
+
Anal. Calcd. for C H OS [M ]: 250.0452. Found (EI): [M ],
NMR (CDCl ): δ 1.70-1.81 (m, 4 H), 2.52-2.57 (m, 2 H), 2.70-
16 10
3
2.76 (m, 2 H), 3.89 (s, 3 H), 6.76 (d, 1 H, J = 8.4 Hz), 7.16 (d, 1
250.0451.