and dilute with water. Extract the oily ester 7a produced with dichloromethane (3 x 20 ml). Mix the organic
extracts and remove the solvent (finally under reduced pressure). Add 5% aqueous solution of KOH (30 ml) to
the residue, boil for 2 h. Acidify the filtrate with dilute HCl (1:1) to pH 3. Filter the precipitate of acid 8a, wash
1
with cold water, and dry. The yield is 1.84 g (85%); mp 118-120ºC (ethanol). H NMR spectrum, , ppm (J,
Hz): 14.57 (1H, br. s, COOH); 8.96 (1H, s, H-4); 8.11 (1H, d, J = 8.1, H-5); 7.95 (1H, t, J = 7.8, H-7); 7.81 (1H,
d, J = 8.5, H-8); 7.47 (1H, t, J = 7.0, H-6); 4.43 (2H, q, J = 7.2, NCH2); 1.27 (3H, t, J = 7.2, CH3). Found, %:
C 66.23; H 4.98; N 6.36. C12H11NO3. Calculated, %: C 66.35; H 5.10; N 6.45.
Compounds 8b-d were prepared by the analogous method.
2-Oxo-1-propyl-1,2-dihydroquinoline-3-carboxylic Acid (8b). For characteristics see [14].
1-Butyl-2-oxo-1,2-dihydroquinoline-3-carboxylic Acid (8c). Yield 76%; mp 135-137ºC (ethanol).
1H NMR spectrum, , ppm (J, Hz): 14.60 (1H, br. s, COOH); 8.95 (1H, s, H-4); 8.11 (1H, dd, J = 8.1 and
J = 1.4, H-5); 7.87 (1H, td, J =7.8 and J = 1.4, H-7); 7.79 (1H, d, J = 8.4, H-8); 7.46 (1H, td, J = 7.2 and J = 1.4,
H-6); 4.37 (2H, t, J = 7.5, NCH2); 1.65 (2H, m, NCH2CH2); 1.41 (2H, m, NCH2CH2CH2); 0.92 (3H, t, J = 7.3,
CH3); Found, %: C 68.69; H 6.27; N 5.65. C14H15NO3. Calculated, %: C 68.56; H 6.16; N 5.71.
1-Isobutyl-2-oxo-1,2-dihydroquinoline-3-carboxylic Acid (8d). Yield 72%; mp 121-123ºC (ethanol).
1H NMR spectrum, , ppm (J, Hz): 14.69 (1H, br. s, COOH); 8.98 (1H, s, H-4); 8.11 (1H, d, J = 8.0, H-5); 7.86
(1H, t, J = 7.7, H-7); 7.79 (1H, d, J = 8.3, H-8); 7.47 (1H, t, J = 7.1, H-6); 4.29 (2H, d, J = 7.4, NCH2); 2.18 (1H,
m, CH(CH3)2); 0.92 (6H, d, J = 6.7, CH(CH3)2. Found, %: C 68.70; H 6.24; N 5.82. C14H15NO3. Calculated, %:
C 68.56; H 6.16; N 5.71.
1-Ethyl-2-oxo-1,2-dihydroquinoline-3-carboxylic Acid 2-(Diethylamino)ethylamide Hydrochloride (5a).
Add N,N'-carbonyldiimidazole (1.78 g, 0.011 mol) to the solution of acid 8a (2.17 g, 0.01 mol) in anhydrous
DMF (15 ml) protecting from the moisture of the air by a CaCl2 tube and keep at 80ºC until the evolving of CO2
stops (for about 1 h). Then add 2-(dethylamino)ethylamine (1.42 ml, 0.01 mol) and keep at the same temperature
for 2 h. Remove the solvent under reduced pressure. Add water (15 ml) to the residue, acidify to pH about
4 using HCl, and then treat with sodium hydrosulphite (0.1 g) and carbon. Filter the product and add NaOH
solution to the filtrate adjusting pH ~ 8. Extract the oily precipitate of the amide base with dichloromethane
(3×20 ml). Mix the organic extracts, distil the solvent simultaneously removing the water remained as an
azeotrope. Transfer the amide base obtained to the target hydrochloride 5a as described before in the synthesis
of the 4-chloro-substituted quinoline-3-carboxylic acid 2-(diethylamino)ethylamide hydrochloride 2. The yield
1
is 2.73 g (78%); mp 170-172 (anhydrous ethanol). H NMR spectrum, , ppm (J, Hz): 10.30 (1H, br. s, NH+);
9.93 (1H, t, J = 5.8, CONH); 8.85 (1H, s, H-4); 8.03 (1H, dd, J = 7.9 and J = 1.3, H-5); 7.78 (1H, td, J = 7.7 and
J = 1.3, H-7); 7.70 (1H, d, J = 8.0 H-8); 7.44 (1H, td, J = 7.1 and J = 1.3, H-6); 4.38 (2H, q, J = 7.1, 1-NCH2;
3.71 (2H, q, J = 6.0, CONHCH2); 3.16 (6H, m, N(CH2)3); 1.23 (9H, m, 3 CH3). Found, %: C 61.35; H 7.32;
N 12.07. C18H25N3O2·HCl. Calculated, %: C 61.44; H 7.45; N 11.94.
Compounds 5b-d were prepared by the analogous method.
2-Oxo-1-propyl-1,2-dihydroquinoline-3-carboxylic Acid 2-(Diethylamino)ethylamide Hydro-
1
chloride (5b). Yield 80%; mp 151-153ºC (anhydrous ethanol). H NMR spectrum, , ppm (J, Hz): 10.41 (1H,
br. s, NH+); 9.94 (1H, t, J = 5.9, CONH); 8.84 (1H, s, H-4); 8.02 (1H, d, J = 8.0, H-5); 7.76 (1H, t, J = 7.8, H-7);
7.69 (1H, d, J = 8.2, H-8); 7.36 (1H, t, J = 7.2, H-6); 4.29 (2H, t, J = 7.6, 1-NCH2); 3.72 (2H, q, J = 6.2,
CONHCH2); 3.16 (6H, m, N(CH2)3); 1.66 (2H, m, NCH2CH2CH3); 1.22 (6H, t, J = 7.2, N(CH2CH3)2); 0.96 (3H,
t, J = 7.4, NCH2CH2CH3). Found, %: C 62.46; H 7.82; N 11.60. C19H27N3O2·HCl. Calculated, %: C 62.37;
H 7.71; N 11.48.
1-Butyl-2-oxo-1,2-dihydroquinoline-3-carboxylic Acid 2-(Diethylamino)ethylamide Hydro-
chloride (5c). Yield 75%; mp 117-119ºC (acetone). 1H NMR spectrum, , ppm (J, Hz): 10.37 (1H, br. s, NH+);
9.94 (1H, t, J = 5.9, CONH); 8.85 (1H, s, H-4); 8.02 (1H, d, J = 7.9, H-5); 7.77 (1H, t, J = 7.8, H-7); 7.67 (1H, d,
J = 8.4, H-8); 7.36 (1H, t, J = 7.1, H-6); 4.33 (2H, t, J = 7.3, 1-NCH2); 3.72 (2H, q, J = 6.3, CONHCH2); 3.19
854