[CH2:1]([C:3]1[C:15]([OH:16])=[C:14]([CH3:17])[C:13]([CH3:18])=[C:12]2[C:4]=1[C:5](=O)[CH2:6][C:7]1([O:11]2)[CH2:10][CH2:9][CH2:8]1)[CH3:2].Cl.[CH3:21][O:22][NH2:23]>N1C=CC=CC=1>[CH3:21][O:22][N:23]=[C:5]1[C:4]2[C:12](=[C:13]([CH3:18])[C:14]([CH3:17])=[C:15]([OH:16])[C:3]=2[CH2:1][CH3:2])[O:11][C:7]2([CH2:10][CH2:9][CH2:8]2)[CH2:6]1To a solution of 5-ethyl-6-hydroxy-7,8-dimethylspiro[chromene-2,1′-cyclobutan]-4(3H)-one (0.51 g) in 9 mL of pyridine was added methoxyamine hydrochloride (0.82 g). The reaction mixture was allowed to stir at room temperature overnight. The mixture was extracted with ethyl acetate, washed with 1N HCl, and concentrated in vacuo to give 5-ethyl-6-hydroxy-7,8-dimethylspiro[chromene-2,1′-cyclobutan]-4(3H)-one O-methyloxime, 1H-NMR (300 MHz, CDCl3) δ=4.58 (s, 1H, 4.01 (s, 3H), 3.05 (m, 2H), 3.02 (s, 2H), 2.20 (s, 3H), 2.17 (s, 3H), 2.10-1.60 (m, 6H), 1.24 (t, 3H) ppm. 13C-NMR (75 MHz, CDCl3) δ=151.0, 147.4, 146.3, 125.8, 124.6, 124.3, 115.3, 76.9, 61.9, 33.9, 33.4, 21.2, 13.6, 12.7, 12.3, 12.1 ppm. MS: (m/z)=290.1 (M+H+).
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