Job/Unit: O43315
/KAP1
Date: 15-12-14 12:37:05
Pages: 12
Isoindoles by One-Electron Reductions of Dibenzodiazocines
DMSO): δ = 7.58 (dd, J = 6.7, 3.0 Hz, 2 H), 7.39–7.34 (m, 4 H),
7.31–7.28 (m, 4 H), 7.22–7.18 (m, 2 H), 6.99 (dd, J = 6.7, 3.0 Hz,
2 H), 6.79 (d, J = 7.8 Hz, 1 H), 6.46 (br. s, 1 H), 6.28 (dd, J = 8.1,
1.9 Hz, 1 H), 4.74 (s, 2 H), 2.14 (s, 3 H) ppm. 13C NMR (100 MHz
[D6]DMSO): δ = 144.7, 138.5, 131.7, 129.6, 129.3, 128.1, 126.3,
124.0, 122.6, 122.0, 120.6, 119.5, 116.8, 115.5, 21.0 ppm. MS (EI+):
m/z = 374 [M]+, 297 [M – Ph]+. HRMS (EI+): calcd. for C27H22N2
359.1699 [M – H]+; found 359.1703. UV/Vis (MeCN): λmax
[log(ε/m–1 cm–1)] = 200, 232 [4.6], 272 [4.1], 305 [4.0], 372 nm [4.2];
emission (MeCN): λ = 443 nm.
131.8, 129.9, 129.7, 129.1, 128.1, 124.7, 122.0 ppm. MS (EI+): m/z
= 358 [M]+, 281 [M – Ph]+. Diazocine 2a was further characterized
by X-ray crystallography (see the Supporting Information).[26]
(5Z,11Z)-8-Methyl-6,11-diphenyldibenzo[b,f][1,4]diazocine (2b): The
general procedure was followed by using 1,2-dibenzoyl-4-methyl-
benzene (8; 1.20 g, 4.00 mmol), AcOH (50 mL), and o-phenylene-
diamine (portion 1: 475 mg, 4.40 mmol; portion 2: 560 mg,
5.18 mmol). Column chromatography (silica gel, cyclohexane/
1
EtOAc, 20:1) yielded 694 mg (47%) of 2b. Rf = 0.10 (CH2Cl2). H
NMR (400 MHz, CDCl3): δ = 7.83–7.80 (m, 4 H), 7.44–7.33 (m, 6
H), 7.18 (ddd, J = 7.9, 1.7, 0.8 Hz, 1 H), 7.04 (d, J = 7.9 Hz, 1 H),
7.02–6.96 (m, 4 H), 6.95 (ddd, J = 1.5, 0.8 Hz, 1 H), 2.32 (s, 3
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 170.1, 170.0, 142.2,
139.0, 138.2, 136.6, 133.7, 131.0, 129.8, 129.1, 128.4, 128.3, 127.7,
127.2, 124.1, 124.1, 121.4, 21.5 ppm. MS (ESI+): m/z = 767 [2M +
Na]+, 745 [2M + H]+, 395 [M + Na]+, 373 [M + H]+. HRMS
(ESI+): calcd. for C27H20N2Na 395.1519 [M + Na]+; found
359.1521.
In the purification process 1f could be obtained in pure form; how-
ever, 1j could only be obtained in a mixture with 1f.
Analytical Data for 2-(1,3-Diphenyl-2H-isoindol-2-yl)-5-methylanil-
ine (1j): Rf = 0.54 (CH2Cl2/NEt3, 100:1). 1H NMR (400 MHz, [D6]-
DMSO): δ = 7.60 (dd, J = 6.5, 3.0 Hz, 2 H), 7.38–7.35 (m, 4 H),
7.31–7.28 (m, 4 H), 7.22–7.18 (m, 2 H), 7.00 (dd, J = 6.5, 3.3 Hz,
2 H), 6.87 (dd, J = 8.4, 2.1 Hz, 1 H), 6.72 (d, J = 2.0 Hz, 1 H),
6.59 (d, J = 8.2 Hz, 1 H), 4.64 (s, 2 H), 2.02 (s, 3 H) ppm.
(5Z,11Z)-8-Methoxy-6,11-diphenyldibenzo[b,f][1,4]diazocine (2c):
The general procedure was followed by using 1,2-dibenzoyl-4-
methoxybenzene (9; 180 mg, 569 μmol), AcOH (9 mL), and o-
phenylenediamine (portion 1: 61.5 mg, 569 μmol; portion 2:
61.5 mg, 569 μmol). Column chromatography (silica gel, cyclohex-
ane/EtOAc, 20:1) yielded 171 mg (77%) of 2c. Rf = 0.33 (cyclohex-
2-(1,3-Diphenyl-2H-isoindol-2-yl)-4-methoxyaniline (1g) and 2-(1,3-
Diphenyl-2H-isoindol-2-yl)-5-methoxyaniline (1k): The general
procedure was followed by using Na (29.0 mg, 1.28 mmol), naphth-
alene (130 mg, 1.02 mmol), and (5Z,11Z)-2-methoxy-6,11-diphen-
yldibenzo[b,f][1,4]diazocine (2g; 40.0 mg, 102 μmol). Column
chromatography (silica gel, cyclohexane/CH2Cl2/NEt3, 2:1:0.01) af-
forded a mixture of 1g and 1k (24 mg, 62%) in a ratio of 96:4.
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ane/EtOAc, 10:1). H NMR (400 MHz, CDCl3): δ = 7.83–7.79 (m,
4 H), 7.44–7.39 (m, 2 H), 7.38–7.33 (m, 4 H), 7.06 (d, J = 8.5 Hz,
1 H), 7.01–6.94 (m, 4 H), 6.90 (dd, J = 8.6, 2.6 Hz, 1 H), 6.63 (d,
J = 2.5 Hz, 1 H), 3.74 (s, 3 H) ppm. 13C NMR (75 MHz, CDCl3):
δ = 169.9, 169.5, 159.7, 142.2, 142.1, 138.4, 138.1, 137.9, 131.1,
131.0, 129.2, 129.1, 128.8, 128.8, 128.4, 128.3, 124.2, 124.1, 121.4,
115.0, 112.1, 77.2, 55.5 ppm. MS (EI+): m/z = 388 [M]+, 373 [M –
Me]+ 311 [M – Ph]+. HRMS (EI+): calcd. for C27H20N2O+
388.1570 [M]+; found 388.1573.
Analytical Data for 2-(1,3-Diphenyl-2H-isoindol-2-yl)-4-methoxy-
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aniline (1g): Rf = 0.43 (CH2Cl2/NEt3, 100:1). H NMR (400 MHz,
[D6]DMSO): δ = 7.59 (dd, J = 6.7, 3.0 Hz, 2 H), 7.38–7.28 (m, 8
H), 7.23–7.18 (m, 2 H), 6.99 (dd, J = 6.6, 3.0 Hz, 2 H), 6.82 (d, J
= 8.6 Hz, 1 H), 6.21 (d, J = 2.7 Hz, 1 H), 6.05 (dd, J = 8.6, 2.7 Hz,
1 H), 4.84 (s, 2 H), 3.64 (s, 3 H) ppm. 13C NMR (75 MHz [D6]
DMSO): δ = 159.8, 146.1, 131.7, 130.7, 129.3, 128.1, 126.3, 124.1,
122.6, 122.0, 119.5, 116.4, 102.1, 99.3, 54.7 ppm. MS (EI+): m/z =
390 [M]+, 313 [M – Ph]+. HRMS (EI+): calcd. for C27H22N2O
390.1727 [M]+; found 390.1730. UV/Vis (MeCN): λmax
[log(ε/m–1 cm–1)] = 197, 231 [4.6], 272 [4.1], 300 [4.1], 372 nm [4.2];
emission (MeCN): λ = 445 nm.
(5Z,11Z)-8-Chloro-6,11-diphenyldibenzo[b,f][1,4]diazocine (2d): The
general procedure was followed by using 4-chloro-1,2-dibenzo-
ylbenzene (10; 350 mg, 1.09 mmol), AcOH (15 mL), and o-phen-
ylenediamine (portion 1: 130 mg, 1.20 mmol; portion 2: 130 mg,
1.20 mmol). Column chromatography (silica gel, cyclohexane/
1
General Procedure for the Preparation of [1,4]diazocines 2a–2i: Ac-
cording to a modified literature method,[19] the respective 1,2-di-
benzoylbenzene was dissolved in AcOH. The respective o-phen-
ylenediamine was added, and the reaction mixture was stirred at
60–80 °C for 5 h. A further 1–4 portions of the respective o-phen-
ylenediamine were added, and the solution was stirred at 50–80 °C
for 9–65 h. The mixture was neutralized with satd. aq. Na2CO3,
extracted with CH2Cl2, washed with brine, and dried (Na2SO4).
The solvent was then removed under reduced pressure. Column
chromatography (silica gel, CH2Cl2 and/or cyclohexane/EtOAc) af-
forded [1,4]diazocines 2a–2i as yellow solids.
CH2Cl2, 1:1) yielded 304 mg (72%) of 2d. Rf = 0.26 (CH2Cl2). H
NMR (400 MHz, CDCl3): δ = 7.79–7.77 (m, 4 H), 7.46–7.41 (m, 2
H), 7.39–7.35 (m, 5 H), 7.15 (d, J = 2.1 Hz, 1 H), 7.09 (d, J =
8.3 Hz, 1 H), 7.04–6.95 (m, 4 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 169.4, 168.6, 141.4, 141.0, 138.1, 137.1, 137.1, 135.4,
134.7, 131.7, 131.7, 129.5, 129.3, 129.2, 128.8, 128.6, 128.6, 127.3,
124.8, 124.7, 121.6, 121.6 ppm. MS (EI+): m/z = 392 [M]+, 359 [M –
Ph]+. HRMS (EI+): calcd. for C26H17ClN2 392.1075 [M]+; found
392.1086.
(5Z,11Z)-8-Bromo-6,11-diphenyldibenzo[b,f][1,4]diazocine (2e): The
general procedure was followed by using 4-bromo-1,2-dibenzo-
(5Z,11Z)-6,11-Diphenyldibenzo[b,f][1,4]diazocine (2a): The general ylbenzene (11; 198 mg, 542 μmol), AcOH (9 mL), and o-phenylene-
procedure was followed by using 1,2-dibenzoylbenzene (7; 2.67 g, diamine (portion 1: 61.0 mg, 564 μmol; portion 2: 61.0 mg,
9.32 mmol), AcOH (120 mL), and o-phenylenediamine (portion 1: 564 μmol; portion 3: 50.0 mg, 462 μmol; portion 4: 61.0 mg,
1.01 g, 9.32 mmol; portion 2: 0.76 g, 6.99 mmol). Column 564 μmol). Column chromatography (silica gel, cyclohexane/
chromatography (silica gel, cyclohexane/EtOAc, 15:1) yielded
EtOAc, 20:1) yielded 181 mg (76%) of 2e. Rf = 0.50 (cyclohexane/
2.83 g (84%) of 2a. Rf = 0.27 (cyclohexane/EtOAc, 15:1). 1H NMR EtOAc, 10:1). 1H NMR (400 MHz, CDCl3): δ = 7.80–7.77 (m, 4
(400 MHz, CDCl3): δ = 7.81 (dd, J = 8.3, 1.5 Hz, 4 H), 7.44–7.34
(m, 8 H), 7.15 (dd, J = 5.7, 3.3 Hz, 2 H), 7.01–6.95 (m, 4 H) ppm.
H), 7.52 (dd, J = 8.2, 2.0 Hz, 1 H), 7.46–7.41 (m, 2 H), 7.40–7.33
(m, 4 H), 7.30 (d, J = 2.0 Hz, 1 H), 7.07–6.95 (m, 5 H) ppm. 13C
1H NMR (400 MHz, [D8]THF): δ = 7.82–7.78 (m, 4 H), 7.41–7.36 NMR (100 MHz, CDCl3): δ = 169.0, 168.3, 141.5, 141.4, 138.4,
(m, 4 H), 7.35–7.30 (m, 4 H), 7.14 (dd, J = 5.7, 3.3 Hz, 2 H), 6.93–
6.84 (m, 4 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 169.9, 142.1, 124.6, 124.5, 123.3, 121.5, 121.5 ppm. MS (EI+): m/z = 436 [M]+,
137.9, 136.6, 131.1, 129.1, 128.9, 128.4, 127.2, 124.2, 121.3 ppm.
359 [M – Ph]+. HRMS (EI+): calcd. for C26H17BrN2 436.0570
13C NMR (100 MHz, [D8]THF): δ = 170.3, 143.2, 139.1, 137.7, [M]+; found 436.0573.
137.4, 137.3, 135.4, 132.3, 131.5, 130.1, 129.1, 128.9, 128.6, 128.5,
Eur. J. Org. Chem. 0000, 0–0
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