Synthesis
4-amino-7-chloroquinoline is obtained by reacting 7-chloro-4-hydrazinoquinoline ,sodium borohydride with nickel (II) chloride hexahydrate in methanol.To a suspension of 7-chloro-4-hydrazinoquinoline (1.67 g, 8.6 mmol) and nickel (II)
chloride hexahydrate (2.00 g, 8.6 mmol) in methanol (33 ml), sodium borohydride
(0.98 g, 25.8 mmol) was added cautiously while stirring the reaction mixture
vigorously at room temperature and left to react overnight. The reaction mixture
was filtered through celite pad. Water was used to dilute the filtrate layer and then
washed with ethyl acetate. The organic layer was dried with magnesium sulphate
and concentrated in vacuo to give the title compound as a yellow powder (1.09 g,
72%): mp: 143 – 147 ℃ (Lit.: 147 – 148 ℃) ;
vmax/cm-1 3337 s (N-H), 1642 m
(C=N), 1609 m and 1575 m (C=N); δH (300 MHz; DMSO-d6) 8.28 (1H, d, J 5.3,
C(2)H), 8.19 (1H, d, J 9.1, C(5)H), 7.76 (1H, d, J 1.6, C(8)H), 7.39 (1H, dd, J 9.1,
1.6, C(6)H), 7.03 (2H, s, NH2), 6.57 (1H, d, J 5.3, C(3)H); δC (75 MHz; DMSO-d6)
152.0 (Ar-C), 151.1 (C(2)H), 148.9 (Ar-C), 133.7 (Ar-C), 126.8 (C(8)H), 124.8 (C(5)H), 123.9 (C(6)H), 117.0 (Ar-C), 102.7 (C(3)H); m/z (-ES) 179 (100%,
[M+H]- with 35Cl), 181 (35%, [M+H]- with 37Cl); found by +ES 179.0377,
C9H8ClN2 ([M+H]+ with 35Cl), requires 179.0371, error 3.3 ppm.
