Preparation | 8-(4-aminophenyl) -5-methyl-N-propyl-1, 3-dioxocyclopenteno [4,5-G] phthalazine -6(5H)-formamide can be made of 4-(4-acetylaminophenyl)-1, 2-dihydro-1-methyl -6, 7-methylhexanedioxyphthalonitrile is used as the reaction raw material, and propyl isocyanate is formed into urea and then acetyl group is hydrolyzed to obtain the step of preparing 4-(4-acetylaminophenyl)-1, 2-dihydro-1-methyl-2-propylcarbamoyl -6, 7-methyldioxo-phthaloyl hydrazine is used to prepare 4-(4-acetylaminophenyl)-1, 2-Dihydro-1-methyl -6, 7-methylhexanedioxyphthalonitrile (0.10g,0.31mmol) was dissolved in dichloromethane (5mL) and treated with propyl isocyanate (0.5mL) under stirring. After 5 hours, add propyl isocyanate (0.5mL) and stir the mixture for 48 hours. The solvent was blown dry with a nitrogen stream, and the residue was chromatographed on silica gel, eluted with a gradient of 33% hexane/EtOAc to 25% hexane/EtOAc. The obtained product is a light yellow foam solid (108mg,86%). 200 MHz 1H NMR (CDCl3); δ 7.63 (ABq, 4H, J = 9.4 Hz, ArH'), 7.40 (bs, 1H, ArNH), 6.77 (s, 1H, ArH), 6.74 (s, 1H, ArH), 6.62 (t, 1H, J = 8.5 Hz, NHCH2), 6.02 (s, 2H, OCH2O), 5.71 (q, 1H, J = 10.9 Hz, CHCH3), 3.33 (dt, 1H, J = 8.5 Hz, J = 7.8 Hz, NHCHCH2), 2.18 (s, 3H, COCH3), 1.61 ( q, 2H, J =7.8 Hz, CH2CH2CH3), 1.27 (d, 3H, J = 10.9 Hz, CHCH3), 0.98 (t, 3H, J = 7.8 Hz, CH2CH3). Step 2. Preparation of 8-(4-aminophenyl) -5-methyl-N-propyl-1, 3-dioxocyclopenteno [4,5-G] phthalazine -6(5H)-formamide 4-(4-acetylaminophenyl)-1, 2-dihydro-1-methyl-2-propylcarbamoyl -6, 7-methyldioxo-phthaloyl hydrazide (0.10g,0.25mmol) was dissolved in methanol (8mL) solution containing 1N sodium hydroxide (4mL) and heated and refluxed for 72 hours. The solution was cooled to ambient temperature, diluted with EtOAc(30mL), and washed with water (30mL). The water layer was extracted with EtOAc(25mL), and the combined organic layer was dried (MgSO4) and evaporated in vacuum. The crude product was chromatographed on silica gel and eluted with 50% hexane/EtOAc to obtain the pure product, which was a light yellow foam solid (75mg,82%). 200 MHz 1H NMR (CDCl3); δ 7.41 (d, 2H, J = 6.5 Hz, ArH), 6.81 (s, 1H, ArH), 6.77 (d, 2H, J = 6.5 Hz, ArH), 6.71 (s, 1H, ArH), 6.00 (s, 2H, OCH2O), 5.67 (q, 1H, J = 6.7 Hz, CHCH3), 3.85 (brs, 2H, NH2), 3.30 (dt, 2H, J = 8.3 Hz, J = 6.2 Hz, NHCH2CH2) , 1.58 (m, 2H, CH2CH2CH3), 1.24 (d, 3H, J = 6.7 Hz, CHCH3), 0.95 (t, 3H, J = 7.5 Hz, CH2CH3). |