[CH3:1][C:2]1[CH:10]=[C:9]2[C:5]([CH:6]=[N:7][NH:8]2)=[CH:4][C:3]=1[N+:11]([O-:13])=[O:12].ClC1[C:16](=[O:27])[C:17](C#N)=[C:18](C#N)[C:19](=O)[C:20]=1Cl.O1C=CCCC1>C(#N)C>[CH3:1][C:2]1[CH:10]=[C:9]2[C:5]([CH:6]=[N:7][N:8]2[CH:16]2[CH2:17][CH2:18][CH2:19][CH2:20][O:27]2)=[CH:4][C:3]=1[N+:11]([O-:13])=[O:12]6-Methyl-5-nitro-1H-indazole (15.1 g, 85.2 mmol), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) (1.94 g, 8.55 mmol) and 3,4-dihydro-2H-pyran (9.0 ml, 98.4 mmol) were dissolved in acetonitrile (300 ml), and the mixture was heated under reflux for 4.5 hr. The reaction mixture was concentrated under reduced pressure, and the residue was diluted with an ethyl acetate-hexane=1:1 mixed solvent, washed with saturated brine, and dried over anhydrous magnesium sulfate. The insoluble material was filtered off, and the solution was concentrated under reduced pressure. The obtained oil was purified by silica gel column chromatography (ethyl acetate-hexane) to give the title compound (16.0 g, yield 72%) as an orange solid.
Loading…
