[The structures and characteristic infrared spectra of beta-DDB and its derivatives]

The characteristic infrared bands of the 3, 4-methylenedioxy-5-methoxybenzoate, 6-Br-3, 4-methylenedioxy-5-methoxybenzoate, beta-DDB (6, 6'-dimethoxy-4, 5, 4', 5'-dimethylenedioxy-2, 2'-dimethoxycarbonylbiphenyl) and its five derivatives were assigned. The effects of the substituents of these compounds on their IR data were discussed. The results indicated the varying of ester alkyl mainly influences the C=O double band stretching mode, but has little effects on the C=C double band stretching mode of the phenyl. When the H atom was substituted by other substituents, the absorptions of the C=O and C=C both changed.