REACTION OF MORPHINAN-6,8-DIENES WITH AZADIENOPHILES

Reaction of various morphinan dienes, i.e. thebaine (la), N-demethyl-N -formylthebaine (Ib), 6-demethoxythebaine (Ic), beta-dihydrothebaine ( 2a), 4-acetoxy-beta-dihydrothebaine (2b), 7-chloro-6-demethoxythebaine (3a) and 7-bromo-6-demethoxythebaine (3b) with 4-phenyl-4H-1,2,4-tria zoline-3,5-dione (PTAD) gave rise to new Diels-Alder (DA) adducts. DA- reaction of la, Ib and Ic with PTAD led to the products of the p-face attack of the dienophile at the diene unit. The W coupling ((4J)5 beta ,18) in the H-1-NMR spectra was indicative of these structures. alpha- Face addition took place in the case of morphinan dienes with opened r ing E, and a by-product was formed due to the S-E reaction of PTAD wit h the adducts. The structure of these derivatives was confirmed by mea ns 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.