Complete structural and spectral assignment of oxoisoaporphines by HMQC and HMBC experiments

The oxoisoaporphines 2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one, 2,3-dihydro-5-methoxy-7H-dibenzo [de,h] quinolin-7-one, 5-methoxy-6-hydroxy-2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one, 5,6-dimethoxy-2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one and 5,6-methylenedioxy-2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one were prepared by cyclization of phenylethylaminophthalides with polyphosphoric acid or by treating 1-(2-carboxyphenyl)-3,4-dihydroisoquinoline hydrochloride with sulfuric acid at 0°C. The structures were confirmed and ¹H and ¹³C NMR spectra were completely assigned using a combination of one- and two-dimensional NMR techniques.