[Research on substances with antiviral activity. III. Structure of the monosubstituted derivatives of 1 H-benzo-[e] indene-1,3(2H)-dione].

The N.M.R. spectra of 1H-benz[e]indene-1,3(2H)-dione (I), 1H-benz[e]indene-2,3-dihydro-1-one (II), 7-methyl-3H-benz[e]indene-1,2-dihydro-3-one (III) and of their oximes, phenylhydrazones and 4-methylthiosemicarbazones show the preferential substitution at 3 position for monoderivatives of (I). This is very interesting in correlation with the structure-activity relationship of derivatives of (I) and (II), some of which have shown in vitro antiviral action in previous research.