Novel synthetic approaches to the 5,10b-ethano-phenanthridine nucleus of the crinine-type amaryllidaceae alkaloids from isoquinoline
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Date
1999
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Abstract
In an effort to develop an efficient synthetic route to the crinane skeleton from isoquinoline, an unprecedented conversion, several novel reactions have been discovered and explored. N-Benzyl-4,4dialkyldihydroisoquinolmium salts, which can be readily prepared from isoquinoline by utilizing boron-activated enamine alkylation chemistry, undergo facile oxidation with m-chloroperoxybenzoic, acid to afford 3-hydroxy-1-isoquinolones and the corresponding homophthalimides; regioselective sodium borohydride reduction of the latter affords the former. Treatment of 3-hydroxy-1-isoquinolones with sulfinic acid results in the formation of isocarbostyrils by dealkylation or acid-catalyzed dehydrative alkyl migration. In the caw of the 4-spirobutyl system, this reaction sequence represents an efficient entry to the relatively inaccessible 1,2,3,4-tetrahydrophenanthridine nucleus of the crinine, narciclasine, and lycorine type alkaloids.
Contents
Subject
Subject(s)
Isoquinoline
Alkaloids
Alkaloids
Research Projects
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Genre
Dissertation
Description
Format
x, 249 leaves : illustrations
Department
Chemistry and Biochemistry