3194
B. Joseph et al. / Tetrahedron 56 (2000) 3189±3196
Hc), 4.59 (broad d, 1H, Jba10.1 Hz, Ha), 4.99 (ddd, 1H,
ing, the solvent was removed in vacuo. The crude residue
was partitioned between dichloromethane (10 ml) and 10%
sodium hydroxide, then the aqueous phase was separated
and extracted with dichloromethane (2£10 ml). The organic
phase was dried over MgSO4 and evaporated in vacuo. The
crude residue was puri®ed by column chromatography
(eluent petroleum ether±ethyl acetate 7:3) to afford 15
(70 mg, 72%) as crystals; mp 176±1778C (ethyl acetate);
0
Jba10.1 Hz, Jbc8.8 Hz, Jb3 1.4 Hz, Hb), 6.08 (d, 1H,
0
0
J16.0 Hz, CHv), 6.16 (d, 1H, Jb3 1.4 Hz, H3 ), 6.67
(dd, 1H, J5.1, 7.3 Hz, HPyr), 7.09 (dd, 1H, J5.3,
7.7 Hz, HPyr), 7.43±7.62 (m, 8H, 6 HAr12 HPyr), 7.77 (d,
1H, J16.0 Hz, CHv), 8.04 (dd, 1H, J1.3, 5.1 Hz, HPyr),
8.19±8.23 (m, 2H, HAr), 8.28±8.32 (m, 2H, HAr), 8.34 (dd,
1H, J1.9, 5.3 Hz, HPyr); 13C NMR (62.90 MHz, CDCl3) d
38.7 (CH), 50.5 (CH), 52.1 (CH3), 52.7 (CH), 52,9 (CH3),
69.3 (C), 106.6 (CH), 119.0 (CH), 119.5 (CH), 120.9 (C),
121.0 (C), 123.2 (CH), 128,0 (2 CH), 128.7 (2 CH), 128.8 (2
CH), 129.1 (CH), 129.3 (2 CH), 133.6 (CH), 134.4 (CH),
135.1 (CH), 137.7 (C), 138.7 (C), 140.4 (C), 143.1 (CH),
144.8 (CH), 148.1 (CH), 149.1 (C), 157.2 (C), 166.2 (C),
170.3 (CO); Anal. Calcd for C34H28N4O8S2: C, 59.64; H,
4.12; N, 8.18. Found: C, 59.99; H, 4.00; N, 8.31; MS m/z
685 (M11)1.
1
IR (KBr) n 1723 (CO) cm21; H NMR (250 MHz, CDCl3)
d 3.99 (s, 3H, CH3), 7.30 (dd, 1H, J4.8, 8.2 Hz, HPyr),
7.34±7.52 (m, 3H, HAr), 7.59 (t, 1H, J8.0 Hz, HAr), 8.00
(dd, 1H, J1.0, 8.0 Hz, HAr), 8.08 (broad d, 2H, J7.5 Hz,
HAr), 8.58 (dd, 1H, J1.5, 4.8 Hz, HPyr), 8.80 (dd, 1H,
J1.0, 8.0 Hz, HAr), 9.09 (dd, 1H, J1.5, 8.2 Hz, HPyr);
13C NMR (62.90 MHz, CDCl3) d 52.5 (CH3), 117.4 (C),
119.1 (CH), 119.4 (CH), 122.5 (C), 125.9 (C), 126.8
(CH), 127.4 (CH), 127.7 (2 CH), 128.9 (2 CH), 134.1
(CH), 134.6 (CH), 138.4 (C), 138.6 (C), 147.7 (CH),
151.0 (C), 167.2 (CO); Anal. Calcd for C19H14N2O4S: C,
62.29; H, 3.85; N, 7.65. Found: C, 62.07; H, 3.81; N,
7.50; MS m/z 367 (M11)1.
Dimethyl 9-methyl-9H-pyrido[2,3-b]indole-7,8-dicarboxyl-
ate (13). A solution of compound 6 (190 mg, 0.97 mmol)
and dimethyl acetylenedicarboxylate (0.18 ml, 1.46 mmol)
in toluene (10 ml) in a sealed tube was heated at 1108C for
24 h. After cooling, the solvent was removed in vacuo. The
crude residue was puri®ed by column chromatography
(eluent petroleum ether±ethyl acetate 7:3) to afford 13
(143 mg, 40%) as crystals; mp 151±1528C (methanol); IR
Dimethyl 9-(phenylsulfonyl)-9H-pyrido[2,3-b]indole-5,6-
dicarboxylate (16). A solution of 9 (100 mg, 0.2 mmol)
and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (160 mg,
0.7 mmol) in dry toluene was stirred at re¯ux under argon
for 24 h. After cooling, the solution was diluted with
dichloromethane, then washed successively with 10%
sodium hydroxide twice and water once. The organic
layer was dried over MgSO4 and evaporated in vacuo. The
crude residue was puri®ed by column chromatography
(eluent petroleum ether±ethyl acetate 7:3) to afford 16
(70 mg, 71%) as white crystals; mp 169±1708C (methanol);
(KBr) n 1736, 1710 (CO) cm21 1H NMR (250 MHz,
;
CDCl3) d 3.96 (s, 3H, CH3), 3.99 (s, 3H, CH3), 4.10 (s,
3H, CH3), 7.21 (dd, 1H, J4.8, 7.5 Hz, HPyr), 7.92 (d, 1H,
J7.2 Hz, HAr), 8.11 (d, 1H, J7.2 Hz, HAr), 8.33 (dd, 1H,
J1.5, 7.5 Hz, HPyr), 8.58 (dd, 1H, J1.5, 4.8 Hz, HPyr); 13
C
NMR (62.90 MHz, CDCl3) d 28.4 (CH3), 52.6 (CH3), 52.9
(CH3), 114.2 (C), 115.9 (CH), 119.3 (C), 121.0 (CH1C),
121.3 (CH), 125.3 (C), 129.0 (CH), 135.5 (C), 148.0 (CH),
152.8 (C), 166.5 (CO), 169.1 (CO); Anal. Calcd for
C16H14N2O4: C, 64.42; H, 4.73; N, 9.39. Found: C, 64.07;
H, 4.81; N, 9.50; MS m/z 299 (M11)1.
1
IR (KBr) n 1737, 1719 (CO) cm21; H NMR (250 MHz,
CDCl3) d 3.96 (s, 3H, CH3), 4.07 (s, 3H, CH3), 7.30 (dd, 1H,
J4.8, 7.9 Hz, HPyr), 7.40±7.59 (m, 3H, HAr), 8.10 (dd, 1H,
J1.6, 7.9 Hz, HPyr), 8.16 (d large, 2H, J8.2 Hz, HAr), 8.24
(d, 1H, J9.0 Hz, HAr), 8.61 (dd, 1H, J1.6, 4.8 Hz, HPyr),
8.65 (d, 1H, J9.0 Hz, HAr); 13C NMR (62.90 MHz, CDCl3)
d 52.7 (CH3), 53.2 (CH3), 115.4 (CH), 116.3 (C), 119.6
(CH), 119.7 (C), 123.0 (C), 127.7 (2 CH), 129.0 (2 CH),
129.7 (CH), 129.8 (C), 130.1 (CH), 134.4 (CH), 138.2 (C),
140.1 (C), 148.1 (CH), 151.0 (C), 165.7 (CO), 168.7 (CO);
Anal. Calcd for C21H16N2O6S: C, 59.43; H, 3.80; N, 6.60.
Found: C, 59.76; H, 3.97; N, 6.75; MS m/z 425 (M11)1.
Methyl 9-phenylsulfonyl-5,6,7,8-tetrahydro-9H-pyrido[2,3-
b]indole-5-carboxylate (14). Following the procedure used
for the preparation of 13, compound 3 in the presence of
methyl acrylate in toluene gave 14 in 21% yield as an oil; IR
1
(®lm) n 1735 (CO) cm21; H NMR (250 MHz, CDCl3) d
1.88±2.26 (m, 4H, CH2), 3.02±3.32 (m, 2H, CH2), 3.67 (s,
3H, CH3), 3.66±3.80 (m, 1H, CH), 7.12 (dd, 1H, J4.9,
7.8 Hz, HPyr), 7.43±7.58 (m, 3H, HAr), 7.69 (dd, 1H,
J1.2, 7.8 Hz, HPyr), 8.15 (broad d, 2H, J8.2 Hz, HAr),
8.35 (dd, 1H, J1.2, 4.9 Hz, HPyr); 13C NMR (62.90 MHz,
CDCl3) d 20.6 (CH2), 24.5 (CH2), 25.4 (CH2), 38.3 (CH),
52.2 (CH3), 111.9 (C), 118.9 (CH), 121.7 (C), 127.1 (CH),
127.8 (2 CH), 129.0 (2 CH), 133.8 (CH), 137.9 (C), 139.4
(C), 143.9 (CH), 148.5 (C), 173.9 (CO); Anal. Calcd for
C19H18N2O4S: C, 61.61; H, 4.90; N, 7.56. Found: C,
61.35; H, 4.75; N, 7.67; MS m/z 371 (M11)1.
Dimethyl 9H-pyrido[2,3-b]indole-5,6-dicarboxylate (17).
A solution of 16 (80 mg, 0.19 mmol) and freshly prepared
tetrabutylammonium ¯uoride (60 mg, 0.19 mmol) in dry
THF was stirred at re¯ux under argon for 2 h. After cooling,
THF was removed in vacuo. The residue was partitioned
between ethyl acetate (10 ml) and water (10 ml), then the
aqueous phase was separated and extracted with ethyl
acetate (2£5 ml). The organic layer was dried over
MgSO4 and concentrated in vacuo. The crude oil was puri-
®ed by column chromatography (eluent petroleum ether±
ethyl acetate 6:4) to afford 17 (50 mg, 93%) as white crystals;
mp 210±2118C (ethyl acetate); IR (KBr) n 1728, 1715 (CO)
Methyl 9-(phenylsulfonyl)-9H-pyrido[2,3-b]indole-5-car-
boxylate (15). Method A: Following the procedure used for
the preparation of 14, compound 3 in the presence of methyl
propynoate in toluene gave 15 in 21% yield as crystals.
1
cm21; H NMR (250 MHz, CDCl3) d 3.96 (s, 3H, CH3),
4.15 (s, 3H, CH3), 7.26 (dd, 1H, J5.0, 7.8 Hz, HPyr), 7.60
(d, 1H, J8.5 Hz, HAr), 8.17 (d, 1H, J8.5 Hz, HAr), 8.27
(dd, 1H, J1.5, 7.8 Hz, HPyr), 8.57 (dd, 1H, J1.5, 5.0 Hz,
HPyr), 11.23 (s, 1H, NH); 13C NMR (62.90 MHz, CDCl3) d
Method B: A solution of 14 (160 mg, 0.27 mmol) and 2,3-
dichloro-5,6-dicyano-1,4-benzoquinone (150 mg, 0.65 mmol)
in toluene (10 ml) was heated at re¯ux for 24 h. After cool-