Chemistry of Heterocyclic Compounds 2017, 53(5), 553–559
CH2); 1.85 (3H, s, COCH3); 3.40–3.55 (2H, m, CH2); 7.89–
Synthesis of N-(6-oxo-2,3,4,6-tetrahydrobenzo[f]-
quinoxalin-5-yl)acetamides 6a–j (General method).
Ethylenediamine (210 mg, 233 μl, 3.5 mmol) was added to
a suspension of the appropriate 2-acetamido-3-chloro-1,4-
naphthoquinone 5a–j (3.5 mmol) in acetonitrile (30 ml).
The reaction mixture was stirred at room temperature and
monitored by TLC (EtOAc). Once the reaction was
complete, the mixture was concentrated under reduced
pressure. The obtained residue was purified by chromato-
graphy (EtOAc) to give the pure product.
7.97 (2H, m, H Ar); 8.03–8.16 (2H, m, H Ar). 13C NMR
spectrum (100 MHz, CDCl3), δ, ppm: 11.4; 21.6; 22.3;
49.7; 127.6; 130.9; 131.3; 134.7; 134.9; 143.6; 145.7;
169.1; 177.8; 179.8.
N-Butyl-N-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-
2-yl)acetamide (5e). Yield 1.30 g (71%), yellow-brown
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oil. H NMR spectrum (400 MHz, DMSO-d6), δ, ppm
(J, Hz): 0.83 (3H, t, J = 7.2, CH3); 1.14–1.32 (2H, m, CH2);
1.35–1.56 (2H, m, CH2); 1.85 (3H, s, COCH3); 3.43–3.60
(2H, m, CH2); 7.87–7.98 (2H, m, H Ar); 8.02–8.18 (2H, m,
H Ar). 13C NMR spectrum (100 MHz, CDCl3), δ, ppm:
13.8; 20.3; 22.4; 30.4; 47.9; 127.7 130.9; 131.4; 134.8;
135.0; 143.7; 145.8; 169.1; 177.9; 179.8.
N-(6-Oxo-2,3,4,6-tetrahydrobenzo[f]quinoxalin-5-yl)-
acetamide (6a). Yield 350 mg (39%), reddish-orange
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powder, mp 178–179°C. H NMR spectrum (400 MHz,
DMSO-d6), δ, ppm (J, Hz): 2.01 (3H, s, CH3); 3.20–3.30
(2H, m, CH2); 4.04 (2H, t, J = 6.4, CH2); 7.33 (1H, s, NH);
7.54–7.65 (2H, m, H Ar); 7.88–7.97 (1H, m, H Ar); 8.04–
8.14 (1H, m, H Ar); 8.82 (1H, s, NH). 13C NMR spectrum
(100 MHz, CDCl3), δ, ppm: 24.3; 37.0; 48.2; 112.2; 123.9;
125.8; 130.3; 131.0; 132.1; 133.4; 134.5; 153.7; 169.6;
178.3. Found, m/z: 256.1103 [M+H]+. C14H13N3O2.
Calculated, m/z: 256.1086.
N-(3-Chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-
N-isopropylacetamide (5f). Yield 1.34 g (77%), yellow
powder, mp 75–76°C. 1H NMR spectrum (400 MHz,
DMSO-d6), δ, ppm (J, Hz): 1.18 (3H, d, J = 6.6, CH3); 1.23
(3H, d, J = 6.6, CH3); 1.81 (3H, s, COCH3); 4.16–4.36 (1H,
m, CH); 7.86–8.03 (2H, m, H Ar); 8.03–8.24 (2H, m,
H Ar). 13C NMR spectrum (100 MHz, CDCl3), δ, ppm:
20.8; 20.9; 23.2; 51.5; 127.8; 130.9; 131.4; 134.8; 135.1;
145.2; 145.7; 168.8; 177.9; 180.7.
N-Methyl-N-(6-oxo-2,3,4,6-tetrahydrobenzo[f]quin-
oxalin-5-yl)acetamide (6b). Yield 564 mg (60%), orange
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N-(3-Chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-
N-cyclohexylacetamide (5g). Yield 1.79 g (90%), yellow
powder, mp 165–166°C. H NMR spectrum (400 MHz,
CDCl3), δ, ppm (J, Hz): 1.89 (3H, s, COCH3); 3.05 (3H, s,
CH3); 3.39–3.56 (2H, m, CH2); 4.18 (2H, t, J = 6.5, CH2);
7.50–7.60 (2H, m, H Ar); 7.95 (1H, s, NH); 8.08–8.13 (1H,
m, H Ar); 8.13–8.19 (1H, m, H Ar). 13C NMR spectrum
(100 MHz, CDCl3), δ, ppm: 21.4; 34.0; 36.5; 48.4; 115.9;
123.8; 126.0; 131.2; 131.5; 131.9; 132.9; 140.3; 153.9;
173.3; 178.0. Found, m/z: 270.1240 [M+H]+. C15H15N3O2.
Calculated, m/z: 270.1243.
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powder, mp 135–136°C. H NMR spectrum (400 MHz,
CDCl3), δ, ppm: 1.20–1.43 (5H, m) and 1.51–1.63 (1H, m,
3CH2); 1.66–1.77 (2H, m, CH2); 1.87 (3H, s, COCH3); 1.90–
2.08 (2H, m, CH2); 4.18–4.37 (1H, m, CH); 7.79–7.91 (2H,
m, H Ar); 8.12–8.30 (2H, m, H Ar). 13C NMR spectrum
(100 MHz, CDCl3), δ, ppm: 22.9; 25.4; 25.9; 31.0; 31.1;
58.8; 127.6; 127.7; 130.9; 131.3; 134.7; 135.0; 145.1;
145.9; 168.5; 177.8; 180.7.
N-Ethyl-N-(6-oxo-2,3,4,6-tetrahydrobenzo[f]quinoxalin-
5-yl)acetamide (6c). Yield 407 mg (41%), orange powder,
N-(3-Chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-
N-phenylacetamide (5h). Yield 1.24 g (64%), orange
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mp 179–180°C. H NMR spectrum (400 MHz, CDCl3),
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powder, mp 136–137°C. H NMR spectrum (400 MHz,
δ, ppm (J, Hz): 1.11 (3H, t, J = 7.2, CH3); 1.89 (3H, s,
COCH3); 3.31–3.56 (2H, m, CH2); 3.70–3.93 (2H, m,
CH2); 4.05–4.31 (2H, m, CH2); 7.41 (1H, s, NH); 7.53–
7.65 (2H, m, H Ar); 8.10–8.17 (1H, m, H Ar); 8.17–8.25
(1H, m, H Ar). 13C NMR spectrum (100 MHz, CDCl3),
δ, ppm: 13.0; 22.0; 36.7; 41.6; 48.5; 114.6; 123.9; 126.3; 131.4;
131.5; 132.0; 132.9; 140.7; 154.0; 172.9; 178.7. Found, m/z:
284.1409 [M+H]+. C16H17N3O2. Calculated, m/z: 284.1399.
N-(6-Oxo-2,3,4,6-tetrahydrobenzo[f]quinoxalin-5-yl)-
N-propylacetamide (6d). Yield 378 mg (36%), yellow
DMSO-d6), δ, ppm: 2.08 (3H, s, COCH3); 7.17–7.61 (5H,
m, H Ar); 7.85–7.99 (2H, m, H Ar); 8.03–8.16 (2H, m,
H Ar). 13C NMR spectrum (100 MHz, CDCl3), δ, ppm:
22.2; 127.5; 127.6; 128.4; 128.7; 129.7; 131.3; 131.4;
134.5; 134.7; 140.2; 143.3; 146.1; 170.9; 178.1; 179.1.
N-Benzyl-N-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-
2-yl)acetamide (5i). Yield 1.76 g (86%), yellow powder,
mp 115–116°C. 1H NMR spectrum (400 MHz, DMSO-d6),
δ, ppm (J, Hz): 1.92 (3H, s, COCH3); 4.65 (1H, d, J = 14.4)
and 4.77 (1H, d, J = 14.4, CH2); 7.10–7.42 (5H, m, H Ar);
7.86–7.97 (2H, m, H Ar); 7.99–8.16 (2H, m, H Ar).
13C NMR spectrum (100 MHz, CDCl3), δ, ppm: 22.5; 50.5;
127.5; 128.0; 128.4; 129.5; 130.7; 131.1; 134.7; 134.9;
135.5; 144.1; 144.9; 169.2; 177.6; 179.4.
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powder, mp 164–165°C. H NMR spectrum (400 MHz,
CDCl3), δ, ppm (J, Hz): 0.86 (3H, t, J = 7.4, CH3); 1.40–
1.67 (2H, m, CH2); 1.89 (3H, s, COCH3); 3.08–3.28 (1H,
m) and 3.61–3.86 (1H, m, CH2); 3.37–3.57 (2H, m, CH2);
4.04–4.33 (2H, m, CH2); 7.47–7.63 (3H, m, NH, H Ar);
8.09–8.16 (1H, m, H Ar); 8.16–8.24 (1H, m, H Ar).
13C NMR spectrum (100 MHz, CDCl3), δ, ppm: 11.7; 21.3;
21.9; 36.7; 48.5; 48.8; 114.9; 123.9; 126.2; 131.4; 131.5;
132.0; 132.8; 140.5; 154.0; 172.9; 178.7. Found, m/z:
298.1564 [M+H]+. C17H19N3O2. Calculated, m/z: 298.1556.
N-Butyl-N-(6-oxo-2,3,4,6-tetrahydrobenzo[f]quinoxalin-
5-yl)acetamide (6e). Yield 345 mg (32%), orange powder,
N-(3-Chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-
N-phenethylacetamide (5j). Yield 1.99 g (94%), yellow
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powder, mp 128–129°C. H NMR spectrum (400 MHz,
DMSO-d6), δ, ppm: 1.89 (3H, s, COCH3); 2.63–3.00 (2H,
m, CH2); 3.53–3.88 (2H, m, CH2); 7.03–7.32 (5H, m,
H Ar); 7.88–8.02 (2H, m, H Ar); 8.04–8.21 (2H, m, H Ar).
13C NMR spectrum (100 MHz, CDCl3), δ, ppm: 22.5; 34.5;
49.0; 126.5; 127.5; 127.6; 128.5; 128.7; 130.9; 131.3;
134.7; 134.9; 138.5; 143.1; 145.6; 169.4; 177.7; 179.7.
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mp 155–156°C. H NMR spectrum (400 MHz, CDCl3),
δ, ppm (J, Hz): 0.87 (3H, t, J = 7.3, CH3); 1.16–1.36 (2H,
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