6628
S. Routier et al. / Tetrahedron 58 (2002) 6621–6630
The residual solid was dissolved in DMSO and the solution
was filtered. DMSO was distillated under reduced pressure
to afford compound 21 as a yellow solid in 88% yield. Mp
2508C dec.; IR (KBr, cm21) n 3440, 2927, 1703, 1487,
4.4.1. 6-Methyl-12,13-dihydropyrrolo[2,3-a]pyrrolo[3,4-
c ]pyrido[30,20:4,5]carbazole-5,7-dione
(24). Bu4NF
(5 equiv.), reaction time 1.5 h, flash chromatography
(petroleum ether/EtOAc 1/9), pale yellow solid, 88%. Mp
2358C dec.; IR (KBr, cm21) n 3932, 3357, 1749, 1694,
1
1356, 1091, 747; H NMR (CDCl3) d: 1.83 (s, 9H, Boc),
1
3.23 (s, 3H, NCH3), 5.25 (s, 2H), 7.08 (dd, 1H, J¼2.8,
9.4 Hz), 7.24–7.29 (m, 1H), 7.33–7.47 (m, 3H), 7.59–7.62
(m, 2H), 7.86 (d, 1H, J¼9.4 Hz), 8.56 (dd, 1H, J¼4.8,
1.5 Hz), 8.91 (d, 1H, J¼2.5 Hz), 9.23 (dd, 1H, J¼7.8,
0.9 Hz), 11.5 (s, 1H, NH); 13C NMR (CDCl3) d: 24.0 (CH3),
28.5 (CH3), 70.4 (CH2), 86.9 (Cq), 108.2 (CH), 114.2 (Cq),
116.8 (CH), 117.0 (Cq), 117.1 (CH), 118.1 (Cq), 118.3
(CH), 121.6 (Cq), 123.9 (Cq), 125.2 (Cq), 127.0 (Cq), 128.2
(2CH), 128.3 (CH), 128.7 (2CH), 129.7 (Cq), 132.8 (Cq),
133.9 (CH), 137.2 (Cq), 148.5 (CH), 151.5 (Cq), 151.8 (Cq),
155.7 (Cq), 169.0 (CO), 169.4 (CO); MS (IS) 547 (MþH)þ.
1383; H NMR (DMSO-d6) d: 2.98 (s, 3H, NCH3), 7.26–
7.33 (m, 2H), 7.50 (t, 1H, J¼7.5 Hz), 7.70 (t, 1H,
J¼7.5 Hz), 8.49 (d, 1H, J¼5 Hz), 8.81 (d, 1H, J¼5 Hz),
8.94 (d, 1H, J¼7 Hz), 11.30 (s, 1H, NH), 11.92 (s, 1H, NH);
13C NMR (DMSO-d6) d: 23.7 (CH3), 111.9 (Cq), 112.3
(CH), 113.2 (Cq), 115.9 (Cq), 116.3 (CH), 119.2 (Cq), 119.5
(Cq), 120.5 (CH), 121.5 (Cq), 124.4 (CH), 127.2 (CH),
127.8 (Cq), 128.8 (Cq), 132.3 (CH), 140.5 (Cq), 146.3 (CH),
152.4 (Cq), 169.6 (CO), 169.7 (CO); MS (IS) 341 (MþH)þ.
Anal. calcd for C20H12N4O2: C, 70.58; H, 3.55; N, 16.46.
Found: C, 70.34; H, 3.68; N, 16.62.
4.3.3. 6-Methyl-10-benzyloxy-13H-pyrrolo[2,3-a ]pyr-
rolo[3,4-c ]pyrido[30,20:4,5]carbazole-5,7-dione-12-car-
boxylic acid tert-butyl ester (22). Irradiation for 1.75 h.
The residual solid obtained after evaporation was triturated
in MeOH. After filtration, compound 22 was obtained as a
yellow solid in 75% yield. Mp 2508C dec.; IR (KBr, cm21) n
3431, 2926, 1705, 1613, 1092; 1H NMR (CDCl3) d: 1.83 (s,
9H, Boc), 3.20 (s, 3H, NCH3), 5.10 (s, 2H), 7.07 (dd, 1H,
J¼7.8, 1.9 Hz), 7.24–7.5 (m, 6H), 7.57 (d, 1H, J¼1.7 Hz),
8.53–8.55 (m, 1H), 9.07 (d, 1H, J¼8.9 Hz), 9.23 (d, 1H,
J¼7.8 Hz), 11.42 (s, 1H, NH); 13C NMR (CDCl3) d: 24.0
(CH3), 28.4 (CH3), 70.2 (CH2), 87.0 (Cq), 101.9 (CH),
113.2 (CH), 112.5 (Cq), 114.4 (Cq), 115.9 (Cq), 116.8 (CH),
117.1 (CH), 118.3 (Cq), 122.0 (Cq), 124.1 (Cq), 126.0 (Cq),
126.6 (CH), 127.6 (2CH), 128.3 (2CH), 128.8 (Cq), 139.9
(CH), 136.7 (Cq), 137.0 (Cq), 148.4 (CH), 151.7 (Cq), 151.8
(Cq), 153.4 (Cq), 169.3 (CO), 169.5 (CO); MS (IS) 547
(MþH)þ.
4.4.2. 6-Methyl-9-benzyloxy-12,13-dihydropyrrolo[2,3-
a ]pyrrolo[3,4-c ]pyrido[30,20:4,5]carbazole-5,7-dione
(25). Bu4NF (10 equiv.), reaction time 2 h, precipitation by
addition of MeOH, filtration, yellow solid, quant. Mp 2908C
1
dec.; IR (KBr, cm21) n 3374, 2924, 1382, 1693, 1222; H
NMR (DMSO-d6) d: 3.11 (s, 3H, NCH3), 5.20 (s, 2H), 7.25
(dd, 1H, J¼9.1, 2.1 Hz), 7.33–7.47 (m, 4H), 7.57–7.60 (m,
2H), 7.70 (d, 1H, J¼8.8 Hz), 8.83–8.54 (m, 2H), 9.06 (dd,
1H, J¼7.8, 1.2 Hz), 11.25 (s, 1H, NH), 12.07 (s, 1H, NH);
13C NMR (DMSO-d6) d: 23.5 (CH3), 69.8 (CH2), 107.4
(CH), 112.7 (Cq), 112.9 (CH), 114.3 (Cq), 116.1 (Cq), 116.6
(CH), 117.1 (CH), 118.7 (Cq), 119.4 (Cq), 121.7 (Cq), 127.6
(Cq), 127.9 (CH), 128.0 (2CH), 128.5 (2CH), 129.1 (Cq),
132.1 (CH), 135.3 (Cq), 137.3 (Cq), 147.2 (CH), 152.9
(Cq), 157.9 (Cq), 169.5 (CO), 169.7 (CO); MS (IS) 447
(MþH)þ.
4.4.3. 6-Methyl-10-benzyloxy-12,13-dihydropyrrolo[2,3-
a ]pyrrolo[3,4-c ]pyrido[30,20:4,5]carbazole-5,7-dione
(26). Bu4NF (10 equiv.), reaction time 2 h, precipitation by
addition of MeOH, filtration, yellow solid, 82%. Mp 2908C
dec.; IR (KBr, cm21) n 3421, 2924, 2054, 1690, 1370, 1132;
1H NMR (DMSO-d6) d: 3.02 (s, 3H, NCH3), 5.24 (s, 2H),
6.99 (d, 1H, J¼8.5 Hz), 7.33–7.57 (m, 7H), 8.45–8.55 (m,
1H), 8.68 (d, 1H, J¼7.7 Hz), 8.99 (d, 1H, J¼8.5 Hz), 11.28
(s, 2H, 2NH); 13C NMR (DMSO-d6) d: 23.4 (CH3), 69.6
(CH2), 96.3 (CH), 111.3 (CH), 112.5 (Cq), 114.2 (Cq),
115.2 (Cq), 116.4 (CH), 118.2 (CH), 118.8 (Cq), 119.2 (Cq),
120.8 (Cq), 124.9 (CH), 127.3 (Cq), 127.9 (CH), 128.3 (Cq),
128.5 (2CH), 131.9 (2CH), 137.1 (Cq), 141.8 (Cq), 147.0
(CH), 152.0 (Cq), 158.6 (Cq), 169.5 (CO), 169.7 (CO); MS
(IS) 447 (MþH)þ.
4.3.4. 6-Methyl-11-benzhydryloxy-13H-pyrrolo[2,3-
a ]pyrrolo[3,4-c ]pyrido[30,20:4,5]carbazole-5,7-dione-12
carboxylic acid tert-butyl ester (23). Irradiation for 1.75 h.
Flash chromatography (EtOAc/MeOH 8/2) then trituration
with MeOH, 77% yield. Mp 2208C dec.; IR (KBr, cm21) n
1
3431, 2954, 2923, 1724, 1693, 1145; H NMR (CDCl3) d:
1.33 (s, 9H, Boc), 3.49 (s, 3H, NCH3), 6.38 (s, 1H), 7.07 (d,
1H, J¼7.8 Hz), 7.25–7.44 (m, 12H), 8.58 (dd, 1H, J¼4.7,
1.6 Hz), 8.87 (d, 1H, J¼7.2 Hz), 9.35 (dd, 1H, J¼7.8,
1.5 Hz), 11.21 (s, 1H, NH); 13C NMR (CDCl3) d: 27.7
(CH3), 35.2 (CH3), 87.5 (CH), 88.7 (Cq), 114.4 (Cq), 115.4
(CH), 117.1 (Cq), 117.3 (CH), 118.9 (CH), 119.1 (Cq),
121.9 (Cq), 123.6 (Cq), 125.4 (CH), 127.2 (Cq), 127.7
(4CH), 128.3 (2CH), 128.8 (4CH), 129.0 (Cq), 130.0 (Cq),
130.9 (Cq), 134.0 (CH), 140.5 (2Cq), 147.8 (Cq), 158.6
(CH), 152.1 (Cq), 152.6 (CO), 169.3 (CO), 169.5 (CO); MS
(IS) 623 (MþH)þ.
4.4.4. 6-Methyl-11-benzhydriloxy-12,13-dihydropyr-
rolo[2,3-a ]pyrrolo[3,4-c ]pyrido[30,20:4,5]carbazole-5,7-
dione (27). Bu4NF (8 equiv.), reaction time 7.5 h, precipi-
tation by addition of MeOH, filtration, yellow solid, quant.
Mp 2548C dec.; IR (KBr, cm21) n 3361, 3915, 2030, 1685,
1298; 1H NMR (DMSO-d6) d: 3.08 (s, 3H, NCH3), 6.91 (s,
1H), 7.14 (d, 1H, J¼8.5 Hz), 7.27–7.46 (m, 9H), 7.64 (d,
3H, J¼7.2 Hz), 8.43 (m, 1H), 8.56 (d, 1H, J¼3.8 Hz), 9.07
(d, 1H, J¼7.5 Hz), 11.55 (s, 1H, NH), 12.06 (s, 1H, NH);
13C-Dept135 NMR (DMSO-d6) d: 24.5 (CH3), 81.36 (CH),
98.3 (CH), 111.6 (CH), 118.0 (CH), 122.03 (CH), 127.9
(4CH), 129.1 (2CH), 130.0 (4CH), 133.4 (CH), 148.6 (CH);
MS (IS) 523 (MþH)þ.
4.4. General procedure for synthesis of compounds
(24–27)
A solution of Bu4NF (1 M in THF) was added at rt to the
desired compounds 20–23 dissolved in dry THF. The
mixture was refluxed. After cooling, the solvents were
removed under reduced pressure and the crude mixture was
purified according the above-described procedure to afford
the desired products 24–27.