Molecules 2014, 19
16748
CHCHO), 7.28 (1H, ddd, J = 7.8, 7.8, 1.0, ArH), 7.34 (1H, dd, J = 8.0, 1.0, ArH), 7.64 (1H, ddd, J = 7.8,
7.8, 1.6, ArH), 8.03 (1H, dd, J = 8.0, 1.6, ArH), 9.72 (1H, d, J = 1.6, CHO); δC (100 MHz, CDCl3): 25.0
(CH2), 27.7 (CH2), 48.8 (CH2), 67.1 (CH), 119.9 (CH), 124.9 (CH), 128.9 (q), 132.5 (CH), 134.4 (CH),
138.2 (q), 200.5 (CH). IR: υmax (thin film cm−1): 820, 865, 999, 1080, 1122, 1156, 1199, 1265, 1287,
1332, 1439, 1471, 1574, 1583, 1603, 1730, 2122, 2953. HRMS (ESI+): compound degraded.
N-(2'-Azidobenzoyl)-2-(carbethoxy-1''-ethenyl)-pyrrolidine (32). The aldehyde 30 [33,34] (273 mg,
1.12 mmol) was dissolved in toluene (10 mL). (Carbethoxymethylene) triphenylphosphorane (390 mg,
1.12 mmol) was added in one portion and the whole was stirred at room temperature under an inert
atmosphere of nitrogen for 12 h before being concentrated in vacuo and purified by silica chromatography
(40 g) (EtOAc/Hex; 3:2) to yield the product 32 in the form of a yellow oil as a mixture of rotamers
(178 mg, 51%). NMR: δH (400 MHz, CDCl3): 1.29 & 1.31 (3H, t, J = 7.1, 2 × COCH2CH3), 1.80–1.99 &
2.01–2.43 (4H, m, CH2), 3.21–3.28 & 3.78–3.86 (1H, m, CHH), 3.34–3.40 & 3.69–3.75 (1H, m, CHH),
4.13 & 4.21 (2H, q, J = 7.1 & 7.1, COCH2CH3), 4.24–4.30 & 4.96–5.00 (1H, m, NCHCH2), 5.46 & 6.15
(1H, dd & d, J = 15.6, 1.1 & 15.6, CHCHCO2Et), 6.59 & 6.94 (1H, dd & dd, J = 15.6, 6.4 & 15.6, 4.9,
CHCHCO2Et), 7.12 (1H, dd, J = 7.5, 7.5, ArH), 7.14 (1H, d, J = 7.3, ArH), 7.19–7.25 (1H, m, ArH),
7.40 & 7.45 (2H, 2 × m, ArH); δC (100 MHz, CDCl3): 14.2/14.3 (CH3), 22.3/23.8 (CH2), 30.5/32.1 (CH2),
46.1/48.2 (CH2), 57.2 (CH), 60.4/60.6 (CH2), 118.5 (CH), 121.2/121.3 (CH), 124.9/125.2 (CH), 127.9
(CH), 129.1/129.5 (q), 130.6 (CH), 133.7/136.2 (q), 146.5 (CH), 165.8/166.5 (q), 167.1/167.4 (q). IR: υmax
(thin film cm−1): 753 (s), 1043 (m), 1093 (m), 1180 (s), 1301 (s), 1369 (m), 1414 (s), 1451 (s), 1475 (m),
1633 (s), 1716 (s), 2130 (s), 2238 (w), 2880 (m), 2979 (m). LRMS (ESI+): Found 315.1 [M+H]+, 337.1
[M+Na]+, 651.3 [2M+Na]+. HRMS (ESI+): Found 315.1451 [M+H]+, C16H18N4O3 + H+ requires 315.1452.
Aziridinopyrrolobenzodiazepine (33). The carbethoxy alkene 32 (178 mg, 0.567 mmol) was heated at
reflux under nitrogen in CHCl3 (10 mL) for 48 h before being concentrated and purified by silica
chromatography (20 g) (EtOAc/Hex; 3:2) to yield the product 33 as a ~1:1 mixture of two
diastereoisomers in the form of a yellow oil (47 mg, 30%). NMR: δH (400 MHz, CDCl3) [mixture of
isomers]: 1.23 (3H, t, J = 7.1, COCH2CH3, isomer “a”), 1.29 (3H, t, J = 7.1, COCH2CH3, isomer “b”),
1.74–1.80 (2H, m, CH2),1.81–2.27 (4H, m, 2 × CH2), 2.77 (1H, d, J = 2.6, CHCO2Et, isomer “a”), 2.87
(1H, d, J = 2.7, CHCO2Et, isomer “b”), 3.08 (1H, dd, J = 9.6, 2.6, ArNCH, isomer “a”), 3.37 (1H, dd,
J = 8.7, 2.7, ArNCH, isomer “b”), 3.57 (1H, ddd, J = 7.3, 7.3, 12.0, CHH), 3.66–3.73 (4H, m, 2 × CH2),
3.74–3.79 (1H, m, CONCH), 3.78–3.87 (1H, m, CHH), 4.20 (2H, quartet, J = 7.1, COCH2CH3, isomer
“a”), 4.23 (2H, quartet, J = 7.1, COCH2CH3, isomer “b”), 4.38 (1H, bd, J = 9.6, CONCH), 6.69 (1H, d,
J = 7.4, ArH), 6.94 (1H, ddd, J = 7.5, 7.5, 0.9, ArH), 7.01 (1H, ddd, J = 7.5, 7.5, 1.0, ArH), 7.07 (1H,
d, J = 8.0, ArH), 7.19 (1H, ddd, J = 7.6, 7.6, 1.6, ArH), 7.28 (1H, ddd, J = 7.7, 7.8, 1.6, ArH), 7.70 (2H,
dd, J = 7.8, 1.8, ArH); δC (100 MHz, CDCl3): 14.2 (CH3), 14.5 (CH3), 23.1 (CH2), 25.6 (CH2), 29.5
(2 × CH2), 42.6 (CH), 46.4 (CH2), 47.0 (CH), 50.4 (CH), 56.6 (CH), 57.2 (CH), 60.1 (CH), 61.4 (CH2),
62.0 (CH2), 68.0 (CH2), 121.3 (CH), 122.0 (CH), 123.1 (CH), 123.3 (CH), 125.3 (q), 126.6 (q), 130.7
(CH), 131.0 (CH), 132.0 (CH), 132.2 (CH), 142.9 (q), 148.1 (q), 166.0 (q), 166.3 (q), 167.9 (q), 168.8
(q). IR: υmax (thin film cm−1): 752 (m), 1024 (s), 1178 (s), 1217 (s), 1260 (s), 1372 (m), 1454 (m), 1503
(m), 1602 (s), 1622 (s), 1725 (s), 2871 (m), 2926 (m), 2977 (m). LRMS (ESI+): Found. 309.1 [M+Na]+.
HRMS (ESI+): Found 309.1206 [M+Na]+, C16H18N2O3 + Na+ requires 309.1210.