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112.3, 126.4, 126.8, 127.6, 128.1, 128.3, 129.5, 129.7, 134.0,
134.1, 137.5, 161.5, 164.6; FAB MS: m/z 342 (M + 1); elemental
analysis for C17H9Cl2N3O: calcd: C, 59.67; H, 2.65; N, 12.28%;
found: C, 59.60; H, 2.57; N, 12.24%.
5,6-Bis(4-chlorophenyl)-3-oxo-2,3-dihydropyridazine-4-carbo-
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nitrile (2d). M.P. 268–270 C; yield: 6.36 g (93%); H NMR (300
MHz, CDCl3): d 7.30–7.45 (m, 6H, Ar-H), 7.87–7.89 (d, 2H, Ar-H),
14.42 (s, 1H, –NH); 13C NMR (75 MHz, CDCl3): d 126.2, 130.5,
130.6, 131.2, 133.1, 167.2; FAB MS: m/z 342 (M + 1); elemental
analysis for C17H9Cl2N3O: calcd: C, 59.67; H, 2.65; N, 12.28%;
found: C, 59.61; H, 2.59; N, 12.20%.
3-Oxo-5,6-di-p-tolyl-2,3-dihydropyridazine-4-carbonitrile (2e).
M.P. 287–289 ꢀC; yield: 5.54 g (92%); 1H NMR (300 MHz, CDCl3): d
3.88 (s, 6H, 2 ꢃ CH3), 7.12–7.36 (m, 6H, Ar-H), 7.51–7.65 (d, 1H,
Ar-H), 7.73–7.98 (d, 1H, Ar-H), 12.37 (s, 1H, –NH); 13C NMR (75
MHz, CDCl3): d 20.3, 127.1, 127.3, 127.9, 128.1, 128.5, 128.8,
129.3, 130.1, 132.2, 132.8, 136.9, 142.9, 165.6, 167.5; FAB MS: m/z
302 (M + 1); elemental analysis for C19H15N3O: calcd: C, 75.73; H,
5.02; N, 13.94%; found: C, 75.68; H, 4.99; N, 13.89%.
Scheme 2 Proposed reaction mechanism.
5,6-Bis(3-nitrophenyl)-3-oxo-2,3-dihydropyridazine-4-carbo-
ethanol. The resultant mixture was kept in freezer for 10
minute. Then, white crystalline 2-cyanoacetohydrazide was
formed. The solid product was ltered and washed with cold
ethanol.
M.P. 104–105 ꢀC; yield: 0.17 g (86%); FAB MS: m/z 100 (M + 1);
elemental analysis for C3H5N3O: calcd: C, 36.36; H, 5.09; N,
42.41%; found: C, 36.31; H, 5.06; N, 42.39%.
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nitrile (2f). M.P. 302–305 C; yield: 6.54 g (90%); H NMR (300
MHz, DMSO): d 7.07–8.73 (m, 8H, Ar-H), 14.41 (s, 1H, NH); 13
C
NMR (75 MHz, DMSO): d 123.7, 127.3, 130.5, 135.4, 147.9, 166.0;
FAB MS: m/z 364 (M + 1); elemental analysis for C17H9N5O5:
calcd: C, 56.20; H, 2.50; N, 19.28%; found: C, 56.14; H, 2.45; N,
19.23%.
5,6-Di(naphthalen-1-yl)-3-oxo-2,3-dihydropyridazine-4-carbo-
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nitrile (2g). M.P. 165–170 C; yield: 7.09 g (95%); H NMR (300
MHz, CDCl3 + DMSO): d 7.35–7.61 (m, 6H, Ar-H), 7.86–7.89 (d,
2H, Ar-H), 7.99–8.02 (d, 2H, Ar-H), 8.24–8.26 (d, 2H, Ar-H), 9.00–
3.3 Procedure for the preparation of 3-oxo-5,6-disubstituted-
2,3-dihydropyridazine-4-carbonitrile
A mixture of the cyanoacetylhydrazide (20 mmol), substituted 9.03 (d, 2H, Ar-H), 12.18 (s, 1H, NH); 13C NMR (75 MHz, CDCl3 +
benzil (20 mmol) and CCSO nano catalyst (20 mg) was added in DMSO): d 124.3, 125.8, 125.9, 127.2, 127.5, 128.2, 130.2, 131.2,
100 ml round bottom ask. The reaction mixture was heated at 132.8, 133.6, 165.0, 169.5; FAB MS: m/z 374 (M + 1); elemental
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110 C for 2–4 minute. Firstly, the reaction mixture melts and analysis for C25H15N3O: calcd: C, 80.41; H, 4.05; N, 11.25%;
become solid. The completion of reaction monitored through found: C, 80.37; H, 4.01; N, 11.19%.
TLC. The solid product was dissolved in minimum amount of
5,6-Bis(4-methoxyphenyl)-3-oxo-2,3-dihydropyridazine-4-carbo-
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ethanol (5 ml) through heating and ltered. The residue was nitrile (2h). M.P. 235–236 C, yield: 6.45 g (93%), H NMR (300
ltered and dried. In ltrate, ice cold water was added for MHz, Si(CH3)4, CDCl3): d 4.04 (s, 3H, OCH3), 7.19–8.47 (m, 8H, Ar-
precipitation. The precipitate was ltered and washed with H), 14.19 (s, 1H, –NH); 13C NMR (75 MHz, CDCl3): d 112.4, 125.9,
excess of water and got 100% pure product. The product was 134.4, 164.9; FAB MS: m/z 334 (M + 1); elemental analysis for
recrystallized from ethyl acetate (5 ml) to yield pure product.
3-Oxo-5,6-diphenyl-2,3-dihydropyridazine-4-carbonitrile (2a). H, 4.56; N, 12.59%.
M.P. 270–272 ꢀC; yield: 5.14 g (94%); 1H NMR (300 MHz, CDCl3): d
5,6-Bis(4-nitrophenyl)-3-oxo-2,3-dihydropyridazine-4-carbo-
C19H15N3O3: calcd: C, 68.46; H, 4.54; N, 12.61%; found: C, 68.42;
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7.08–7.45 (m, 10H, Ar-H), 11.62 (s, 1H, –NH); 13C NMR (75 MHz, nitrile (2i). M.P. 302–305 C; yield: 6.93 g (92%); H NMR (300
CDCl3): d 113.4, 113.9, 127.9, 128.4, 128.5, 128.7, 129.1, 129.9, MHz, Si(CH3)4, CDCl3): d 7.65–8.70 (m, 8H, Ar-H); 13C NMR (75
133.3, 134.7, 145.9, 151.8, 157.5; FAB MS: m/z 274 (M + 1); MHz, CDCl3): d 122.75, 125.39, 126.39, 129.51, 130.08, 130.48,
elemental analysis for C17H11N3O: calcd: C, 74.71; H, 4.06; N, 131.60, 132.13, 132.94, 143.74, 147.71, 166.12, 166.77; FAB MS:
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15.38%; found: C, 74.59; H, 4.01; N, 15.27%.
m/z 364 (M + 1); elemental analysis for C17H9N5O5: calcd: C,
5,6-Dimethyl-3-oxo-2,3-dihydropyridazine-4-carbonitrile (2b). 56.20; H, 2.50; N, 19.28%; found: C, 56.14; H, 2.45; N, 19.23%.
M.P. 209–211 ꢀC; yield: 3.07 g (94%); 1H NMR (300 MHz, Si(CH3)4,
CDCl3): d 2.34 (s, 3H, CH3), 2.49 (s, 3H, CH3), 11.28 (s, 1H, NH);
FAB MS: m/z 150 (M + 1); elemental analysis for C7H7N3O: calcd:
4. Conclusion
C, 56.37; H, 4.73; N, 28.17%; found: C, 56.21; H, 4.68; N, 28.32%. Conclusion part of the manuscript clearly says that if the reac-
5,6-Bis(2-chlorophenyl)-3-oxo-2,3-dihydropyridazine-4-carbo- tion can be carried out under ecofriendly condition, why to
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nitrile (2c). M.P. 263–265 C; yield: 6.5 g (95%); H NMR (300 divert towards hazardous organic chemicals. Importance and
MHz, CDCl3): d 7.04–7.41 (m, 6H, Ar-H), 7.61–7.87 (d, 1H, Ar-H), need of substituted pyridazine nucleus in pharmaceutics as well
7.90–7.96 (d, 1H, Ar-H); 13C NMR (75 MHz, CDCl3): d 104.1, as a catalyst enforced to synthesize in bulk, thus the aforesaid
51242 | RSC Adv., 2014, 4, 51239–51243
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