S. Nandi et al. / Tetrahedron 60 (2004) 3663–3673
3671
by TLC). The reaction mixture was then cooled, filtered
through a sintered funnel and the residue was washed with
ethanol. The combined filtrate was evaporated under
reduced pressure and the residue was dissolved in chloro-
form (50 mL), washed with water (2£50 mL), dried
(Na2SO4) and concentrated to give the crude product
which was purified by column chromatography using
hexane–ethyl acetate (8:2) as eluent.
NMR (400 MHz, CDCl3): d 2.35 (quintet, J¼7.3 Hz, 2H,
CH2), 3.22 (t, J¼7.5 Hz, 2H, CH2), 3.23 (s, 3H, CH3), 3.39
(t, J¼7.5 Hz, 2H, CH2), 7.50 (s, 1H, ArH), 7.66–7.80 (m,
2H, ArH), 7.85 (t, J¼5.8 Hz, 2H, ArH), 8.02 (dd, J¼1.4,
7.5 Hz, 1H, ArH), 9.01 (d, J¼8.3 Hz, 1H, ArH); 13C NMR
(100 MHz, CDCl3): d 24.5 (CH2), 27.5 (CH3), 31.6 (CH2),
33.4 (CH2), 124.2 (CH), 125.1 (CH), 125.3 (CH), 127.0
(CH), 127.2 (CH), 127.7 (CH), 128.3 (C), 128.6 (CH), 129.9
(C), 132.1 (C), 132.9 (C), 133.7 (C), 138.9 (C), 141.2 (C);
MS (m/z, %): 232 (Mþ, 100); Anal. calcd for C18H16
(232.33): C, 93.05; H, 6.94%. Found: C, 93.01; H, 6.87%.
4.5.1. 3-Methoxy-5-methylbenzo[c]phenanthrene (15b).
White crystalline solid (chloroform–hexane); Rf 0.8 (8:2
hexane–EtOAc); Yield 77%; mp 91–92 8C; IR (KBr):
2925, 1608, 1502, 1427 cm21
;
1H NMR (400 MHz,
4.5.5. 1,2,3,4-Tetrahydro-5-methylchrysene: 1,2,3,4-
tetrahydrochrysene (30/29). White solid (chloroform–
hexane); Rf 0.93 (8:2 hexane–EtOAc); mp 107–113 8C;
CDCl3): d 2.67 (s, 3H, CH3), 3.93 (s, 3H, OCH3), 7.25
(dd, J¼3.2, 9.2 Hz, 1H, ArH), 7.39 (d, J¼2.4 Hz, 1H, ArH),
7.47–7.55 (m, 2H, ArH), 7.57 (s, 1H, ArH), 7.64 (d,
J¼8.0 Hz, 1H, ArH), 7.72 (d, J¼8.0 Hz, 1H, ArH), 7.89 (dd,
J¼1.2, 7.6 Hz, 1H, ArH), 8.91 (d, J¼8 Hz, 1H, ArH), 8.96
(d, J¼9.2 Hz, 1H, ArH); 13C NMR (100 MHz, CDCl3): d
19.9 (CH3), 55.3 (OCH3), 104.8 (CH), 115.8 (CH), 125.0
(C), 125.3 (CH), 125.8 (CH), 126.0 (C), 126.4 (CH), 127.6
(CH), 127.7 (CH), 127.9 (CH), 128.4 (CH), 129.4 (C), 129.9
(C), 130.1 (CH), 132.1 (C), 133.2 (C), 134.6 (C), 157.4 (C);
MS (m/z, %): 272 (Mþ, 100); Anal. calcd for C20H16O
(272.35): C, 88.20; H, 5.92%. Found: C, 88.15; H, 5.99%.
1
Yield 66%; IR (KBr): 2964, 1619, 1503, 1466 cm21; H
NMR (400 MHz, CDCl3): d 1.85–1.92 (m, 4H, (CH2)2),
[1.96–2.01 (m, 4H, (CH2)2)], 2.93 (t, J¼6 Hz, 2H, CH2),
[2.97 (t, J¼6 Hz, 2H, CH2)], 3.08 (s, 3H, CH3), 3.18
[quintet, J¼6 Hz, 4H, (CH2)2], 7.24 (s, 1H, ArH), 7.38 (d,
J¼8.5 Hz, 1H, ArH), 7.54–7.64 (m, 4H, ArH), 7.76 (t,
J¼9 Hz, 2H, ArH), 7.89 (t, J¼9 Hz, 2H, ArH), 7.96 (d,
J¼4.8 Hz, 1H, ArH), 7.97 (d, J¼4.8 Hz, 1H, ArH), 8.48 (d,
J¼8.5 Hz, 1H, ArH), 8.67 (d, J¼8.2 Hz, 1H, ArH), 8.85 (d,
J¼8.2 Hz 1H, ArH); 13C NMR (100 MHz, CDCl3): d 16.4
(CH2), 18.7 (CH2), 19.7 (CH2), 27.3 (CH3), 28.0 (CH2), 28.8
(CH2), 29.9 (CH2), 32.4 (CH2), 36.5 (CH2), 110.2 (CH),
113.3 (CH), 114.3 (C), 118.2 (C), 119.2 (CH), 119.9 (CH),
123.8 (C), 124.6 (C), 125.4 (C), 125.8 (CH), 126.5 (C),
126.8 (CH), 126.9 (CH), 127.5 (C), 127.6 (CH), 127.9 (CH),
128.4 (CH), 128.5 (CH), 128.6 (C), 129.0 (C), 130.8 (C),
133.5 (CH), 134.8 (CH), 137.5 (C), 145.7 (CH), 148.7 (C),
152.4 (C), 153.4 (CH); MS (m/z, %): 248 (Mþþ2, 100), 246
(Mþ, 11), 233 (Mþþ1, 73), 232 (Mþ, 17).
4.5.2. 2,3-Dimethoxy-5-methyl-7,8-dihydrobenzo[c]-
phenanthrene (15c). White crystalline solid (chloroform–
hexane); Rf 0.53 (8:2 hexane–EtOAc); Yield 78%; mp
1
147–148 8C; IR (KBr): 2924, 1623, 1515, 1488 cm21; H
NMR (400 MHz, CDCl3): d 2.63 (s, 3H, CH3), 2.80 (s, 4H,
–(CH2)2), 3.96 (s, 3H, OCH3), 4.03 (s, 3H, OCH3), 7.12 (s,
1H, ArH), 7.23 (d, J¼8.8 Hz, 1H, ArH), 7.24 (s, 1H, ArH),
7.31–7.36 (m, 2H, ArH), 7.94 (d, J¼7.5 Hz, 1H, ArH), 7.97
(s, 1H, ArH); 13C NMR (100 MHz, CDCl3): d 19.7 (CH3),
29.7 (CH2), 30.3 (CH2), 55.75 (OCH3), 55.77 (OCH3),
103.4 (CH), 105.5 (CH), 125.8 (C), 125.9 (CH), 126.0 (CH),
126.3 (CH), 127.5 (CH), 127.8 (CH), 128.4 (C), 128.8 (C),
132.1 (C), 134.7 (C), 135.3 (C), 139.7 (C), 148.3 (C), 149.1
(C); MS (m/z, %): 304 (Mþ, 100); Anal. calcd for C21H20O2
(304.39): C, 82.86; H, 6.62%. Found: C, 82.94; H, 6.55%.
4.5.6. 1,4-Dimethylphenanthrene (37). White crystalline
solid (chloroform–hexane); Rf 0.81 (8:2 hexane–EtOAc);
Yield 72%; mp 112–113 8C; IR (KBr): 2925, 1588, 1458,
1
1378; H NMR (400 MHz, CDCl3): d 2.73 (s, 3H, CH3),
3.11 (s, 3H, CH3), 7.34 (d, J¼7.3 Hz, 1H, ArH), 7.38 (d,
J¼7.8 Hz, 1H, ArH), 7.55–7.64 (m, 2H, ArH), 7.75 (d,
J¼9 Hz, 1H, ArH), 7.91 (d, J¼7.3 Hz, 1H, ArH), 7.95 (d,
J¼9 Hz, 1H, ArH), 8.88 (d, J¼9.2 Hz, 1H, ArH); 13C NMR
(100 MHz, CDCl3): d 27.3 (CH3), 29.6 (CH3), 123.4 (CH),
125.3 (CH), 125.6 (CH), 126.8 (CH), 127.3 (CH), 127.6
(CH), 128.4 (CH), 130.2 (C), 130.6 (CH), 131.8 (C), 132.1
(C), 132.7 (C), 133.0 (C), 133.3 (C); MS (m/z, %): 206 (Mþ,
88); Anal. calcd for C16H14 (206.29): C, 93.15; H, 6.84%.
Found: C, 93.21; H, 6.75%.
4.5.3. 2,3-Dimethoxy-5-methyl-7H-benzo[c]fluorene
(21c). White crystalline solid (chloroform–hexane); Rf
0.83 (8:2 hexane–EtOAc); Yield 88%; mp 204–205 8C; IR
(KBr): 2925, 1624, 1518, 1493 cm21; 1H NMR (400 MHz,
CDCl3): d 2.70 (s, 3H, CH3), 3.94 (s, 2H, CH2), 4.05 (s, 3H,
OCH3), 4.14 (s, 3H, OCH3), 7.31 (s, 1H, ArH), 7.32 (t,
J¼5.3 Hz, 1H, ArH), 7.42 (s, 1H, ArH), 7.46 (dd, J¼6.8,
7.3 Hz, 1H, ArH), 7.60 (d, J¼7.6 Hz, 1H, ArH), 8.02 (s, 1H,
ArH), 8.19 (d, J¼7.8 Hz, 1H, ArH); 13C NMR (100 MHz,
CDCl3): d 20.2 (CH3), 37.4 (CH2), 55.6 (OCH3), 55.8
(OCH3), 103.5 (CH), 104.1 (CH), 121.7 (CH), 122.7 (CH),
124.8 (CH), 125.14 (CH), 125.16 (C), 126.6 (CH), 127.9
(C), 132.2 (C), 133.4 (C), 140.5 (C), 142.9 (C), 144.0 (C),
148.1 (C), 149.4 (C). MS (m/z, %): 290 (Mþ, 100). Anal.
calcd for C20H18O2 (290.36): C, 82.73; H, 6.24%. Found: C,
82.67; H, 6.18%.
4.6. Procedure for acid-induced hydrolysis-decarboxyl-
ation of 13b: synthesis of 17b
A suspension of 13b (5 mmol) in water (5 mL), AcOH
(5 mL), and concentrated H2SO4 (5 mL) was refluxed with
stirring at 180 8C for 6 h (monitored by TLC). It was then
cooled, poured into ice-cold water (25 mL), neutralized with
saturated NaHCO3 solution and extracted with CHCl3
(3£50 mL). The combined organic layer was dried
(Na2SO4), evaporated to give crude viscous residue that
was purified by column chromatography over silica gel
with hexanes–EtOAc (98:2) as eluent to give the pure
product.
4.5.4. 11-Methyl-16,17-dihydro-15H-cyclopenta[a]-
phenanthrene (5b). Colorless crystalline solid (chloro-
form–hexane); Rf 0.9 (8:2 hexane–EtOAc); Yield 88%; mp
1
80–81 8C; IR (KBr): 2963, 1654, 1513, 1452 cm21; H