HETEROCYCLES, Vol. 77, No. 2, 2009
1407
thermometer
was
charged
palladium
acetate
(4.89
mg,
0.022
mmol)
and
bis[2-(diphenylphosphino)phenyl] ether (DPEphos) (17.6 mg, 0.033 mmol) under the nitrogen
atmosphere. Anhydrous toluene (25 mL) was added portionwise over 5 min. After the addition, the
solution was stirred for 5 min at rt under the nitrogen current. 7-Amino-5,8-dimethylisoquinoline (3) (75
mg, 0.436 mmol), 2,4-dinitro-1-bromobenzene (0.90 g, 0.65 mmol) and solid NaOt-Bu (0.064 g, 0.65
mmol) was added. Then, the flask was purged for 5 min with nitrogen, and the mixture was stirred at
100 ℃ for 24 h. When the reaction was complete, the solution was extracted organic layer with CHCl3
and water. The organic layer was washed by aq. NaCl, dried (MgSO4) and evaporated under reduced
pressure to give yellow solid. The crude product was purified by chromatography on silica gel using
AcOEt as the eluant, affording the product as a yellow solid. The solid was recrystallised from
methylcyclohexane to afford a yellow crystal of 7-(2,4-dinitroanilino)-5,8-dimethylisoquinoline (4a)
1
(1.71 g, 32%), mp 181~182 ℃, IR (KBr, cm-1) 3334, 1269 (NH), 1590, 1325 (N = O); H-NMR (500
MHz, CDCl3): δ 9.96 (1H, s, CH arom.), 9.95 (1H, s, CH arom.), 9.22 (1H, s, CH arom.), 8.71 (1H, d, CH
arom., J = 5.7 Hz), 8.18 (1H, d, CH arom., J = 9.5 Hz), 7.83 (1H, d, CH arom., J = 5.7 Hz), 7.38 (1H, s,
CH arom.), 6.77 (1H, s, NH), 2.68 (3H, s, CH3), 2.64 (3H, s, CH3); 13C-NMR (CDCl3, 125 MHz): 149.9,
147.3, 143.9, 137.5, 135.2, 134.4, 131.0, 129.8, 129.4, 128.3, 124.1, 117.2, 116.0, 18.5, 12.7.
HRMS (FAB) (m/z): Calcd for C17H14N4O4: 339.1094. Found M+: 339.1100.
7-(4-Methyl-2-nitroanilino)-5,8-dimethylisoquinoline (4b) The same palladium-catalyzed coupling
above was used as for compound (4a), such that 45% of 4b was isolated. mp 158~159 ℃, IR (KBr,
1
cm-1): 3339, 1262, (NH), 1522, 1344 (N = O); H-NMR (500 MHz, CDCl3): δ 9.51 (1H, s, CH arom.),
9.35 (1H, s, CH arom.), 8.63 (1H, d, CH arom., J = 5.9 Hz), 8.05 (1H, s, CH arom.), 7.78 (1H, d, CH
arom., J = 5.9 Hz), 7.42 (1H, s, CH arom.), 7.18 (1H, d, CH arom., J = 8.7 Hz), 6.68 (1H, s, NH), 2.65
13
(3H, s, CH3), 2.64 (3H, s, CH3), 2.31(3H, s, CH3); C-NMR (CDCl3, 125 MHz): 149.7, 143.0, 141.6,
137.3, 134.7, 134.4, 133.2, 132.7, 129.9, 128.6, 128.2, 127.2, 126.0, 117.2, 116.0, 20.1, 18.4, 12.5
HRMS (FAB) (m/z): Calcd for C18H17N3 O2: 308.1399. Found M+: 308.1398.
7-(4-Fluoro-2-nitroanilino)-5,8-dimethylisoquinoline (4c) The same palladium-catalyzed coupling
above was used as for compound (4a), such that 37% of 4c was isolated. mp 198~199 ℃, IR (KBr, cm-1)
1
3280, 1257 (NH), 1512, 1345 (N = O), 1258 (C-F); H-NMR (500 MHz, CDCl3): δ 9.52 (1H, s, CH
arom.), 9.34 (1H, s, CH arom.), 8.65 (1H, d, CH arom., J = 5.5 Hz), 7.98 (1H, d, CH arom.), 7.78 (1H, d,
CH arom., J = 6.0 Hz), 7.39 (1H, t, CH arom.), 7.15 (1H, s, CH arom.), 6.73 (1H, s, NH), 2.66 (3H×2, s,
CH3); 13C-NMR (CDCl3, 125 MHz): 149.8, 143.3, 140.7, 134.6, 134.3, 133.6, 129.8, 128.7, 124.7, 124.5,
117.4, 117.3, 117.2, 112.2, 112.0, 18.4, 12.5.
HRMS (FAB) (m/z): Calcd for C17H14FN3 O2: 312.1148. Found M+: 312.1150.
7-(2-Nitroanilino)-5,8-dimethylisoquinoline (4d) The same palladium-catalyzed coupling above was