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Palladium‐Catalyzed 2‐Phenylethenylation of Codeine: 8‐[(1 E )‐2‐Phenylethenyl]codeinone Dimethyl Ketal as the Unexpected ‘Masked’ Diene for the Preparation of 19‐Substituted Diels–Alder Adducts of Thebaine
Author(s) -
Kalinin Valery N.,
Shishkov Igor V.,
Moiseev Sergey K.,
Shults Elvira E.,
Tolstikov Genrikh A.,
Sosnitalia I.,
Petrovskii Pavel V.,
Lyssenko Konstantin A.,
Schmidhammer Helmut
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690088
Subject(s) - thebaine , chemistry , adduct , methyl vinyl ketone , derivative (finance) , medicinal chemistry , diene , catalysis , codeine , ketone , organic chemistry , morphine , medicine , natural rubber , financial economics , economics , pharmacology
In a search for starting materials for the preparation of 7,8‐fused morphine alkaloid derivatives, 8‐[(1 E ‐2‐phenylethenyl]codeinone dimethyl ketal ( 4 ) and 8‐[(1 E ‐2‐phenylethenyl]codeine ( 5 ) were prepared. These dienes were used as substrates in the Diels–Alder reactions. Compound 5 formed the ‘normal’ adduct 12 with N‐ phenylmaleimide, while compound 4 behaved in reactions with dienophiles as the ‘masked’ diene 11 , a 8‐[(1 E )‐2‐phenylethenyl]‐substituted thebaine, yielding the corresponding 19‐substituted 6,14‐ endo ‐etheno‐6,7,8,14‐tetrahydrothebaines. Specifically, reaction of 4 with methyl vinyl ketone gave rise to 19‐[(1 E )‐phenylethenyl]thevinone ( 14 ) whose structure was elucidated by an X‐ray diffraction analysis. The thebaine derivative 11 was also prepared from 4 .