2-cyclobutylidene-N-(4-methoxy-2,3-dimethylphenyl)acetamide → 6'-hydroxy-7',8'-dimethyl-1'H-spiro[cyclobutane-1,4'-quinolin]-2'(3'H)-one

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Reaction Steps

A solution of 2-cyclobutylidene-N-(4-methoxy-2,3-dimethylphenyl)acetamide (5 g) in methane sulfonic acid (20 mL) was refluxed at 120° C. overnight. After cooling down, the solution was poured onto ice. The solid present was collected by filtration and washed with water (×3), giving 6′-hydroxy-7′,8′-dimethyl-1′H-spiro[cyclobutane-1,4′-quinolin]-2′(3′H)-one (2.5 g) which was used in the next step without further purification. 1H-NMR (300 MHz, CDCl3) δ=6.8 (s, 1H); 3.37 (s, 1H); 2.64 (s, 2H); 2.43 (m, 3H); 2.16 (s, 6H); 2.07 (m, 3H) ppm. MS: (m/z)=232 (100, M+H+).

Provenance & Evidence