Secophthalide-isoquinolines

When discussing seco alkaloids the question of their genesis should not be disregarded. Are they true alkaloids or artifacts of isolation It is difficult to answer this question with certainty. Some of them, e.g., secophthalide-isoquinoline ene lactams, are postulated to be formed during the extraction process however, most of them are believed to be metabolites produced naturally. This may be evidenced by the fact that some of these alkaloids retain optical activity, and in addition many of them can be synthesized in biomimetic syntheses in the laboratory. Thus, one can generalize the opinion of Shamma (10), whose significant contribution to the field of secoisoquinoline alkaloids should be acknowledged, that [a process]. .. could presumably occur in vivo at least as readily as it could in vitro. ... 

The second illustration above is a phthalide THIQ, and these phenethylamines are sometimes referred to as secophthalide-isoquinolines. Here, the oxygen atom of the original isofuranone ring is substituted on the newly formed double bond. This structure can easily open up to the corresponding ketonic carboxylic acid. These seco-modifications of the attacked isoquinoline (first example, illustrated with an aporphine) and the simpler 1-substituted isoquinolines (second example, as illustrated by the isobenzofuranone) are the only ones included in this book. The standard phenethylamines that are commonly found in cacti, compounds which are not from these seco-mecha-nisms, have been tabulated in TIHKAL and will not be repeated here. 

---

See also in sourсe #XX -- [ ]

---