Quaternary Protoberberine Alkaloids
✍ Scribed by Lenka Grycova; Jiri Dostal; Radek Marek
- Publisher
- John Wiley and Sons
- Year
- 2007
- Weight
- 11 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0931-7597
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## Abstract Adducts of the quaternary protoberberine alkaloids (QPA) berberine, palmatine, and coptisine were prepared with nucleophiles derived from pyrrole, pyrazole, imidazole, and 1,2,4‐triazole. The products, 8‐substituted 7,8‐dihydroprotoberberines, were identified by mass spectrometry and 1D
Photochemical cyclisation of methoxy-substituted g-(1,2,3,4-tetrahydroisoquinolin-2ylmethyl)phthalimides and subsequent treatment of the photoproduct with aqueous acid leads to oxygenated ccmpounds with the protoberberine skeleton.
Feeding experiments with distant single or doubly labelled precursors show that the methylene dioxy group of berberine is opened in the formation of jatrorrhizine.