One-pot synthesis of 3-(furan-2-yl)-4H-chromen-4-ones from 1-(2-hydroxyphenyl)butane-1,3-diones and 2,5-dimethoxy-2,5-dihydrofuran catalyzed via K10 montmorillonite under solvent-free conditions
A new, concise and efficient method of one-potsynthesis of 3-(furan-2-yl)-4H-chromen-4-ones was developed using K10 montmorillonite catalysis undersolvent-freeconditions.
divergent synthesis of chromones and chromanones from a common substrate via reductive coupling cyclization by switching hydrosilanes has been developed. Results of mechanistic studies revealed that under PhMeSiH conditions, the reaction initially undergone cyclization to form chromones , which can subsequently be reduced to yield chromanones . When the hydrosilane was switched to EtSiH, the reaction route
The C=O stretching frequencies of substituted 2-methylchromones (3a-3j). 2-formylchromones (4a-4j), 3-formylchromones (5a-5j) and 3-acetyl-2-methylchromones (6a-6i) were measured in CCl4 and CHCl3 and correlated with sigma+ substituent constants. Using the results of the infrared spectral investigation and the theoretical calculations by the semiempirical AM1 method, the conformation and the transmission of electronic effects in compounds 4-6 were studied. For the 2-substituted chromone system the transmission factory gamma according to the definition of Charton was determined. The preparation of some new 2-methylchromones (3e-3j) and 3-(2,2-diformyl-chlorovinyl)-6-methylchromone (7) is also described.