- Synthesis of optically active aporphine and morphinandienone alkaloids via p-quinol esters
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Lead tetraacetate oxidation of N-trifluoroacetylnorcodamine (5) in (S)-(+)-2-phenylpropionic acid gave a diastereomeric mixture of two p-quinol acylates, which were easily separated to enantiomerically pure 6a and 6b. Treatment of the chiral quinol acylates (6a) and (6b) with trifluoroacetic acid in CH2Cl2 at room temperature afforded (1R)-(-)-6-trifluoroacetylwilsonirine (7a) and (1S)-(+)-(7b), respectively. Saponification of 7a and 7b gave rise to (-)-wilsonirine (8a) and its enantiomer (8b), respectively. Similarly, (-)-nordomesticine (12a) and (+)-(12b) were synthesized in enantiomerically pure form from 10a and 10b. On the other hand, acid treatment of 6a and 6b in CH3CN at lower temperature (-30°C) llowed by N-deprotection gave the corresponding normorphinandienones (15a and 15b) as major products, which were transformed to enantiomerically pure (-)-16a and (+)-sebiferine (16b). In a similar sequence of reactions, (+)-amurine (19a) and its enantiomer (19b) were synthesized.
- Hara,Komoriya,Miyashita,Hoshino
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p. 1683 - 1692
(2007/10/02)
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- Alkaloids of Ocotea acutangula
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The leaves of Ocotea acutangula (Mez) contain, in addition to the known (S)-(-)-pallidine (5) and its new derivative (S)-(-)-O-methylpallidine (6), the new 8,14-dihydromorphinandienone alkaloids (S)-(-)-pallidinine (7) and (S)-(-)-O-methylpallidinine (8) which possess a B/C trans-junction.
- Vecchietti, Vittorio,Casagrande, Cesare,Ferrari, Giorgio,Danieli, Bruno,Palmisano, Giovanni
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p. 578 - 581
(2007/10/02)
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