[OH:1][C:2]1[CH:11]=[C:10]([OH:12])[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[N:3]=1.S([O-])([O-])(=O)=O.[Mg+2].[CH3:19][C:20]([CH3:24])=[CH:21][CH:22]=O>N1C=CC=CC=1.CO.C(Cl)(Cl)Cl>[CH3:19][C:20]1([CH3:24])[O:12][C:10]2[C:9]3[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=3[NH:3][C:2](=[O:1])[C:11]=2[CH:22]=[CH:21]1To a boiling solution of 2,4-dihydroxy quinoline (5.0 g, 31 mmol) in pyridine (300 ml) under argon was added anhydrous magnesium sulfate (20 g) followed by 3-methyl-2-butenal (2.6 g, 31.0 mmole). The reaction was heated under reflux for 16 hours. After 12 hours, more 3-methyl-2-butenal (1.3 g, 15.5 mmol) was added and the reaction was heated under reflux for 16 more hours. The reaction was diluted with 10% methanol in chloroform (200 ml) and filtered while hot. The solid was washed with hot solvent (10% methanol in chloroform) and the filtrate was concentrated in vacuo and coevaporated with toluene. The resulting solid was triturated with isopropyl ether to give the title A compound (4.5 g), m.p. 174° C.-177° C.: 1H NMR (DMSO-d6 /CDCl3) ppm: δ7.7 (d, 1H, J =8.0 Hz), 7.4 (d, 1H, J = 9.0 Hz), 7.2 (d, 1H, J =8.0 Hz), 7.1 (dd, 1H, J =7 & 8 Hz), 6.5 (d, 1H, J =8.0 Hz), 5.5 (d, 1H, J =9.0 Hz), 3.3 (s, 1H), 1.34 (2 s, 6H); 13C NMR (DMSO-d6 /CDCl3) ppm: 160.8, 158.7, 136.5, 128.9, 120.9, 120.2, 119.7, 115.0, 113.6, 113.4, 103.7, 76.7, 26.0.
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