- A new regioselective synthesis of isopavine and pavine alkaloids via double cyclization of N-(1,2-diarylethyl)-N-(2-phenylsulfinylethyl)formamide
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Pummerer reaction of N-[1,2-(3,4-dimethoxyphenyl)ethyl]-N-(2-phenylsulfinylethyl)formamide (9) using trifluoroacetic anhydride and boron trifluoride etherate caused double cyclization to give N-formylisopavine (21). Acid catalyzed cyclization of the 1,2-dihydroisoquinoline (23) prepared from 4-phenylthio-1,2,3,4-tetrahydroisoquinoline (11) gave N-formylpavine (26). LiAlH4 reduction of the N-formates (21 and 26) gave (±)-O-methylthalisopavine (4) and (±)-argemonine (5), respectively.
- Shinohara, Tatsumi,Takeda, Akira,Toda, Jun,Sano, Takehiro
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p. 981 - 992
(2007/10/03)
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- A FACILE ROUTE TO TETRAHYDROISOQUINOLINE ALKALOIDS VIA SULFOXIDE MEDIATED CYCLIZATION
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A facile route to 1,2,3,4-tetrahydroisoquinoline framework has been developed by employing the sulfoxide mediated cyclization reaction.Utilizing the reaction developed some naturally occurring isoquinoline alkaloids have been synthesized.
- Takano, Seiichi,Iida, Hirokazu,Inomata, Kohei,Ogasawara, Kunio
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