Methanol → [E]-4-cyclobutyl-2-[2-(3-nitrophenyl)ethenyl]thiazole

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Reaction Steps

A 1-L round-bottom flask was charged with 28.0 g (0.0968 mol) of crude compound of Example 2, 15.21 g (0.1006 mol) of 3-nitrobenzaldehyde and 400 mL of methanol. The mixture was stirred until a solution was obtained. To this solution was added 40.13 g (0.2903 mol) of powdered potassium carbonate under vigorous stirring and stirring was continued overnight at room temperature. The compound of Example 2 was no longer detectable at this time (TLC, Merck silica gel 60, F-254; 95:5 ethyl acetate methanol). During the reaction time additional solids had precipitated from the solution. The suspension was concentrated at 30° C. bath temperature and 10 torr until a volume of about 200 mL of methanol was removed. To the resulting residue was added 200 mL of water and the mixture was stirred at room temperature for one hour. The solids were collected by filtration under reduced pressure using a sintered-glass funnel of medium porosity. The filter cake was washed with 2×100 mL of water and dried for 16 hours at 30° C. and 10 torr over potassium hydroxide flakes to afford 26.63 g of crude [E]-4-cyclobutyl-2-[2-(3-nitrophenyl)ethenyl]thiazole as a mustard-colored powder (TLC, Merck silica gel 60, F-254; 95:5 ethyl acetate-methanol); 96.1% yield based on crude compound of Example 2 used, 96.76% pure (HPLC).

Provenance & Evidence