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- Marton, J., et al.
(författare)
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Reaction of morphinan-6,8-dienes with azadienophiles
- 1996
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Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 52:7, s. 2449-2464
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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