Infrared Spectra and Theoretical Study of Methyl, Formyl and Acetyl Derivatives of Chromones

Article abstract of DOI:10.1007/BF00819522

The C=O stretching frequencies of substituted 2-methylchromones (3a-j), 2-formylchromones (4a-j), 3-formylchromones (5a-j) and 3-acetyl-2-methylchromones (6a-i) were measured in CCl4 and CHCl3 and correlated with ?⁺ substituent constants.Using the results of the infrared spectral investigation and the theoretical calculations by the semiempirical AM1 methd, the conformation and the transmission of electronic effects in compounds 4-6 were studied.For the 2-substituted chromone system the transmission factory γ according to the definition of Charton was determined.The preparation of some new 2-methylchromones (3e-j) and 3-(2,2-diformyl-chlorovinyl)-6-methylchromone (7) is also described. Key words: 2-Methyl-, 2-formyl-, 3-formyl-, and 3-acetyl-2-methylchromones; infrared spectra; AM1 calculations; conformation; transmission of substituent effects.