PhCH2), 3.28 (br d, 1H, J = 10.6, 9a-CH), 3.76 (s, 3H, OCH3),
3.85 (m, 2H, 3-CH2), 4.25 (d, 1H, J = 13.2, PhCH2), 7.12 (s, 1H,
5-CH), 7.23–7.37 (m, 5H, Ar–H); dC 22.4, 22.5 (C-8 and C-7),
27.9 (C-9), 44.9 (C-2), 49.7 (C-3), 50.6 (OCH3), 57.3 (PhCH2),
59.7 (C-9a), 113.8 (C-6a), 117.0 (C-6), 124.3 (C-5), 127.2, 128.4,
129.0 (3 × Ar–CH), 130.2 (C-9b), 138.4 (Ar–C), 165.9 (CO2CH3);
m/z (EI) 311 (MH+, 10%), 283 (10%), 282 (41%), 191 (39%), 161
(6%), 91 (100%), 49 (21%), 43 (17%). HRMS: (EI) MH+ 311.1763;
C19H22N2O2 requires MH+ 311.1759.
10.0, 12.5, 2-CHH), 2.72 (dddd, 1H, J = 2.1, 5.8, 11.2, 16.8, 7-
CHH), 2.94 (m, 2H, 7-CHH and 2-CHH), 3.12 (d, 1H, J = 13.3,
PhCH2), 3.34 (br d, 1H, J = 10.6, 9a-CH), 3.52 (m, 2H, 3-CH2),
3.60 (s, 3H, OCH3), 4.26 (d, 1H, J = 13.3, PhCH2), 7.26–7.32
(m, 10H, Ar–H); dC 22.5, 23.0 (C-8 and C-7), 28.0 (C-9), 44.2
(C-2), 49.9 (C-3), 50.4 (OCH3), 57.3 (PhCH2), 59.7 (C-9a), 111.2
(C-6a), 117.5 (C-6), 127.1, 127.8, 127.9, 128.3, 128.5, 128.9 (6 ×
Ar–CH), 130.4 (C-9b), 132.0 (C-5), 136.7, 138.3 (2 × Ar–C), 165.9
(CO2CH3); m/z (EI) 387 (MH+, 21%), 359 (26%), 358 (98%), 267
(54%), 237 (22%), 207 (11%), 180 (12%), 167 (8%), 91 (100%), 65
(8%), 49 (4%). HRMS: (EI): MH+ 387.2077; C25H26N2O2 requires
MH+ 387.2072.
Ethyl
1-benzyl-2,3,7,8,9,9a-hexahydro-1H-pyrrolo[1,2,3-de]-
quinoxaline-6-carboxylate (14b). White solid (0.10 g; 30%). Re-
crystallisation from methanol–hexane gave white needles for X-
ray crystallographic analysis: m.p. 122–123 ◦C; mmax (nujol)/cm−1
2942, 2880, 1730, 1698, 1530, 1662, 1175, 1098, 1054, 918, 730;
dH 1.19 (t, 3H, J = 7.1, OCH2CH3), 1.35 (dtd, 1H, J = 2.5, 11.6,
13.5, 9-CHH), 1.65 (dddt, 1H, J = 2.1, 6.0, 11.6, 13.7, 8-CHH),
2.02 (m, 1H, 8-CHH), 2.17 (m, 1H, 9-CHH), 2.36 (ddd, 1H, J =
7.5, 10.0, 12.5, 2-CHH), 2.54 (dddd, 1H, J = 2.1, 5.8, 11.2, 16.8,
7-CHH), 2.75 (dd, 1H, J = 6.4, 16.8, 7-CHH), 2.90 (ddd, 1H,
J = 2.3, 3.9, 12.5, 2-CHH), 3.01 (d, 1H, J = 13.2, PhCHH), 3.16
(br d, 1H, J = 10.6, 9a-CH), 3.72 (m, 2H, 3-CH2), 4.12 (m, 3H,
OCH2CH3 and PhCHH), 7.02 (s, 1H, 5-CH), 7.18–7.25 (m, 5H,
Ar–H); dC 14.6 (OCH2CH3), 22.5, 22.6 (C-8 and C-7), 27.9 (C-9),
45.0 (C-2), 49.8 (C-3), 57.3 (PhCH2), 59.2 (OCH2CH3), 59.7
(C-9a), 114.2 (C-6a), 117.0 (C-6), 124.3 (C-5), 127.3, 128.4, 129.0
(3 × Ar–CH), 129.3 (C-9b), 138.5 (Ar–C), 165.6 (CO2CH2CH3);
m/z (EI) 325 (MH+, 100%), 235 (15%), 233 (12%), 106 (7%),
91 (100%), 65 (18%), 52 (38%). HRMS: (EI) MH+ 325.1921;
C20H24N2O2 requires MH+ 325.1916. Found: C, 73.18; H, 7.35;
N, 8.18%; C20H24N2O2·0.25 MeOH requires C, 73.16; H, 7.58; N,
8.43%;
Ethyl
1-benzyl-5-phenyl-2,3,7,8,9,9a-hexahydro-1H-pyrrolo-
[1,2,3-de]quinoxaline-6-carboxylate (14e). White solid (0.11 g;
31%): m.p. 124–125 ◦C; mmax (nujol)/cm−1 2932, 2857, 1694, 1489,
1414, 1382, 1348, 1264, 1170, 1148, 1067, 773, 736; dH 1.08 (t, 3H,
J = 7.1, OCH2CH3), 1.50 (dtd, 1H, J = 2.5, 11.6, 13.5, 9-CHH),
1.78 (dddt, 1H, J = 2.1, 6.0, 11.6, 13.7, 8-CHH), 2.17 (m, 1H,
8-CHH), 2.32 (m, 1H, 9-CHH), 2.45 (ddd, 1H, J = 7.5, 10.0, 12.5,
2-CHH), 2.73 (dddd, 1H, J = 2.1, 5.8, 11.2, 16.8, 7-CHH), 2.94
(m, 2H, 7-CHH and 2-CHH), 3.12 (d, 1H, J = 13.3, PhCH2),
3.34 (br d, 1H, J = 10.6, 9a-CH), 3.53 (ddd, 1H, J = 7.5, 10.0,
12.5, 3-CHH), 3.63 (ddd, 1H, J = 2.3, 3.9, 12.5, 3-CHH), 4.07 (q,
2H, J = 1.29, 7.1, CO2CH2CH3), 4.26 (d, 1H, J = 13.3, PhCH2),
7.28–7.31 (m, 10H, Ar–H); dC 14.1 (OCH2CH3), 22.5, 22.9 (C-8
and C-7), 28.0 (C-9), 44.2 (C-2), 49.9 (C-3), 57.3 (PhCH2), 58.9
(OCH2CH3), 59.7 (C-9a), 112.8 (C-6a), 117.5 (C-6), 127.1, 127.7,
17.8, 128.3, 128.5, 128.9 (6 × Ar–CH), 130.5 (C-9b), 132.1 (C-5),
138.4 (2 × Ar–C), 165.4 (CO2CH2CH3); m/z (EI) 401 (MH+,
25%), 373 (22%), 372 (100%), 299 (23%), 281 (23%), 253 (34%),
237 (31%), 207 (31%), 178 (28%), 91 (100%), 55 (35%), 43 (68%).
HRMS: (EI) MH+ 401.2234; C26H28N2O2 requires MH+ 401.2229.
tert-Butyl 1-benzyl-2,3,7,8,9,9a-hexahydro-1H-pyrrolo[1,2,3-de]-
quinoxaline-6-carboxylate (14c). Yellow oil (0.14 g; 33%): mmax
(film)/cm−1 2983, 1736, 1698, 1524, 1466, 1374, 1246, 1174, 1096,
1048, 914, 735; dH 1.47 (dtd, 1H, J = 2.5, 11.6, 13.5, 9-CHH), 1.52
(s, 9H, (CH3)3), 1.74 (dddt, 1H, J = 2.1, 6.0, 11.6, 13.7, 8-CHH),
2.08 (m, 1H, 8-CHH), 2.27 (m, 1H, 9-CHH), 2.47 (ddd, 1H, J =
7.5, 10.0, 12.5, 2-CHH), 2.63 (dddd, 1H, J = 2.1, 5.8, 11.2, 16.8,
7-CHH), 2.85 (dd, 1H, J = 6.4, 16.8, 7-CHH), 3.00 (ddd, 1H, J =
2.3, 3.9, 12.5, 2-CHH), 3.12 (d, 1H, J = 13.2, PhCH2), 3.27 (br d,
1H, J = 10.6, 9a-CH), 3.82 (m, 2H, 3-CH2), 4.22 (d, 1H, J = 13.2,
PhCH2), 7.07 (s, 1H, 5-CH), 7.28–7.32 (m, 5H, Ar-H); dC 22.0, 22.6
(C-8 and C-7), 27.8 (C-9), 28.3 ((CH3)3), 44.9 (C-2), 49.7 (C-3),
57.1 (PhCH2), 59.6 (C-9a), 79.1 (OC(CH3)3), 115.7 (C-6a), 116.6
(C-6), 124.1 (C-5), 128.1, 128.3, 128.9 (3 × Ar–CH), 130.5 (C-9b),
138.5 (Ar–C), 165.0 (CO2C(CH3)3); m/z (EI) 353 (MH+, 28%), 324
(21%), 268 (38%), 177 (32%), 91 (100%), 65 (15%), 57 (50%), 41
(33%). HRMS: (EI) MH+ 353.2228; C22H28N2O2 requires MH+
353.2229.
tert-Butyl
rolo[1,2,3-de]quinoxaline-6-carboxylate
1-benzyl-5-phenyl-2,3,7,8,9,9a-hexahydro-1H-pyr-
(14f). White solid
(0.14 g; 34%): m.p. 52–54 ◦C; mmax (nujol)/cm−1 2927, 2855, 1687,
1460, 1377, 1164, 1148; dH 1.27 (s, 9H, (CH3)3), 1.51 (dtd, 1H,
J = 2.5, 11.6, 13.5, 9-CHH), 1.81 (dddt, 1H, J = 2.1, 6.0, 11.6,
13.7, 8-CHH), 2.15 (m, 1H, 8-CHH), 2.30 (m, 1H, 9-CHH), 2.42
(ddd, 1H, J = 7.5, 10.0, 12.5, 2-CHH), 2.74 (dddd, 1H, J = 2.1,
5.8, 11.2, 16.8, 7-CHH), 2.93 (m, 2H, 7-CHH and 2-CHH), 3.09
(d, 1H, J = 13.4, PhCH2), 3.32 (br d, 1H, J = 10.6, 9a-CH),
3.46 (ddd, 1H, J = 7.5, 10.0, 12.5, 3-CHH), 3.57 (ddd, 1H, J =
2.3, 3.9, 12.5, 3-CHH), 4.23 (d, 1H, J = 13.4, PhCH2), 7.26–7.30
(m, 10H, Ar–H); dC 22.5, 22.8 (C-8 and C-7), 27.9 (C-9), 28.1
((CH3)3), 44.0 (C-2), 49.9 (C-3), 57.1 (PhCH2), 59.6 (C-9a), 78.7
(OC(CH3)3), 112.9 (C-6a), 117.3 (C-6), 126.9, 127.6, 127.7, 128.2,
128.3, 128.8 (6 × Ar–CH), 130.4 (C-9b), 132.4 (C-5), 136.8, 138.4
(2 × Ar–C), 164.5 (CO2C(CH3)3); m/z (EI) 429 (MH+, 12%), 401
(21%), 400 (77%), 371 (9%), 355 (7%), 345 (13%), 344 (100%), 253
(8%), 91 (100%), 65 (8%), 57 (43%). HRMS: (EI) MH+ 429.2546;
C28H32N2O2 requires MH+ 429.2542. Found: C, 77.70; H, 7.48;
N, 6.32%; C28H32N2O2·0.25 MeOH requires C, 77.72; H, 7.62; N,
6.42%.
Methyl 1-benzyl-5-phenyl-2,3,7,8,9,9a-hexahydro-1H-pyrrolo-
[1,2,3-de]quinoxaline-6-carboxylate (14d). White solid (0.13 g;
33%). Recrystallisation from methanol–hexane gave white nee-
dles for X-ray crystallographic analysis: m.p. 148–150 ◦C; mmax
(nujol)/cm−1 2932, 2857, 1694, 1489, 1466, 1382, 1348, 1264, 1193,
1170, 1086, 911, 736, 701; dH 1.55 (dtd, 1H, J = 2.5, 11.6, 13.5,
9-CHH), 1.80 (dddt, 1H, J = 2.1, 6.0, 11.6, 13.7, 8-CHH), 2.14
(m, 1H, 8-CHH), 2.33 (m, 1H, 9-CHH), 2.45 (ddd, 1H, J = 7.5,
Methyl (3R,9S)-1-benzyl-3-phenyl-2,3,7,8,9,9a-hexahydro-1H-
pyrrolo[1,2,3-de]quinoxaline-6-carboxylate (14g). White solid
(0.10 g; 30%). Recrystallisation from methanol–hexane gave white
needles for X-ray crystallographic analysis: m.p. 176–176 ◦C; [a]D20
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The Royal Society of Chemistry 2006
Org. Biomol. Chem., 2006, 4, 3155–3165 | 3163
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