%0 Journal Article %A Hewgill, FR %A Pass, MC %T On the Synthesis of 2,12-Dimethoxy-6,7,8,9-tetrahydro-5H-dibenz[d,f]azonine-3,11-diol and the Other Bridged Biphenyldiols and the E.S.R. of Their Oxidation Products in Relation to the Biosynthesis of Erythrina Alkaloids %J Australian Journal of Chemistry %D 1985/04/01 %V 38 %N 4 %P 537-554 %K %R https://doi.org/10.1071/CH9850537 %U https://www.publish.csiro.au/paper/CH9850537 %X An improved synthesis in described for the dibenzazonine precursor of erysodienone . Other biphenyl-4,4′-diols, bridged by two, three and five atoms, were also prepared. E.s.r. examination of the oxidation of these compounds produced spectra of the 9,10-dihydrophenanthrene-4,4′- semiquinone system, hitherto unrecorded, but semiquinone spectra could not be obtained from the other diols.