3-Nitrobenzaldehyde → 6-Methoxy-2,2-dimethyl-3-(3-nitrobenzylidene)chroman-4-one

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Reaction Conditions

Reaction Steps

A mixture of 7.0 g (0.034 mole) of the product of Example 109, 2.5 mL (2.6 g, 0.017 mole) tetramethyl orthosilicate, 1.9 g (0.034 mole) potassium fluoride and 5.1 g (0.034 mole) 3-nitrobenzaldehyde in 10 mL dimethylformamide was heated to 80° C. for 4 hours. The mixture was diluted with ether and washed successively with 1N HCl, 5% NaHCO3, water and brine and then dried (MgSO4) and concentrated to give an oil. Flash chromatography on silica gel eluting with 20% ethyl acetate in hexanes yielded an oil. Recrystallization from ether/hexanes afforded 6.9 g (60%) of the title product as a solid. Mp 103°-105° C. Analysis calculated for C15H17NO5 : C, 67.25; H, 5.05; N, 4.13. Found: C, 67.22; H, 4.87; N, 4.11.

Provenance & Evidence