1H and 13C NMR spectral assignments of novel chromenylchalcones.

Several types of chalcones containing 2H-chromen group were synthesized. Claisen-Schmidt condensation of 2H-chromen-3-carbaldehydes (I) with methoxy substituted acetophenones afforded (E)-3-(2H-chromen-3-yl)-1-(methoxyphenyl)prop-2-en-1-ones (chromenylchalcones, 1-7). Other types of chromenylchalcone, (E)-1-(6-methoxy-2H-chromen-3-yl)-3-(methoxyphenyl)prop-2-en-1-ones (8-13) were also obtained between reaction of methoxy substituted benzaldehydes and 1-(6-methoxy-2H-chromen-3-yl)ethanone (II). Dichromenylchalcones (14-16) were also synthesized through the same reaction between aldehydes (I) and ketone (II). Their complete (1)H-NMR and (13)C-NMR assignments are reported here and more polysubstituted chromenylchalcones synthesized or isolated from the natural sources in the future can be identified on the basis of the NMR data reported here.