33887-71-7Relevant academic research and scientific papers
Reaction of morphinan-6,8-dienes with azadienophiles
Marton, Janos,Szabo, Zoltan,Csorvassy, Istvan,Simon, Csaba,Hosztafi, Sandor,Makleit, Sandor
, p. 2449 - 2464 (1996)
Reaction of various morphinan dienes, i.e. thebaine (1a), N-demethyl-N-formylthebaine (1b), 6-demethoxythebaine (1c), β-dihydrothebaine (2a), 4-acetoxy-β-dihydrothebaine (2b), 7-chloro-6-demethoxythebaine (3a) and 7-bromo-6-demethyoxythebaine (3b) with 4-phenyl-4H-1,2,4-triazoline-3,5-dione (PTAD) gave rise to new Diels-Alder (DA) adducts. DA-reaction of 1a, 1b and 1c with PTAD led to the products of the β-face attack of the dienophile at the diene unit. The W coupling (4J(5β,18)) in the 1H-NMR spectra was indicative of these structures. α-Face addition took place in the case of morphinan dienes with opened ring E, and a by-product was formed due to the S(E) reaction of PTAD with the adducts. The structure of these derivatives was confirmed by means of NMR spectroscopic methods. The retro Diels-Alder (rDA) reaction of the adducts 4a and 4b readily took place in polar-aprotic solvents in the presence of bases with low nucleophilic character.
New Studies and a Reinvestigation on Cycloadditions of (-)-Thebaine: Asymmetrical Diels-Alder Reactions with a Conformationally Fixed Chiral Diene
Pindur, Ulf,Keilhofer, Diana
, p. 947 - 954 (2007/10/02)
Some novel Diels-Alder reactions of the opium alkaloid (-)-thebaine (1) as an electron-rich diene and a reinvestigation of its reactions with cyclic and acyclic dienophiles are described.The ?-facial selectivity has been studied on the basis of structural analyses of the cycloadducts.Some related results on cycloaddition reactions of 1-methoxy-1,3-cyclohexadiene (11) are also reported. - Key Words: (-)-Thebaine / 1,3-Cyclohexadiene, 1-methoxy / Diels-Alder Reactions / Alkaloids
