| Abstract
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Roemeria refracta of Turkish origin had formerly provided a number of alkaloids suspected of belonging to the pavine-isopavine grouping. As a result of the present effort, it was demonstrated that one of these bases, ()-eschscholtzinone, is the first ketonic pavinoid. ()-Norreframidine is the only naturally occurring N-norisopavine. The new isopavine ()-refractamine, structurally isomeric with the known ()-reframoline, was also characterized. The different di, tetra and hexahydro derivatives of the proaporphine (+)-stepharine, which had previously been obtained through catalytic reduction, were studied by various NMR techniques, thus allowing for specific stereochemical assignments. A number of Roemeria proaporphines alkaloids wre subjected to NMR analyses and their structures elucidated. ()-Roemerialinone, ()-isoorientalinone, ()-isoroemerialinone, ()-11,12-dihydroorientalinone, (+)-8,9-dihydroisoroemerialinone and ()-usd\alphausd-roemehybrine were thus identified. Two previously known alkaloids from R. hybrida, namely ()-roehybridine and ()-roemeridine, were shown to belong to the new class of isoquinoline-indole bases formed by Pictet-Spengler condensation of a ketonic tetrahydroproaporphine with a tryptamine analog. Finally, the NMR spectral characteristics of over 100 bisbenzylisoquinoline alkaloids have been presented in tabular form. The use of this extensive data in the structure elucidation of new bisbenzylisoquinolines has been demonstrated.
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