The ethylene glycol ketal of neopinone was prepared in a one-pot procedure by the reaction of thebaine with ethylene glyocol in the presence of p-toluenesulfonic acid. The ketal is also an intermediate in the conversion of thebaine to hydrocodone with ethylene glycol and Pd(OAc)(2), followed by hydrogenation. Additionally, a one-pot procedure for the conversion of thebaine to hydrocodone was achieved by employing palladium catalysis in aqueous medium. Palladium serves a dual purpose in this transformation, first for the activation of the dienol ether of thebaine and second as a hydrogenation catalyst. This procedure was found to be comparable to the two-step protocol which employs diimide reduction of thebaine followed by acid-catalyzed hydrolysis of the resulting 8,14-dihydrothebaine to hydrocodone. Experimental and spectral data are provided for all compounds.
Microbiological syntheses O 0035Processing of Cyclopropylarenes by Toluene Dioxygenase: Isolation and Absolute Configuration of Metabolites. -A series of cyclopropyl substituted arenes is subjected to enzymatic oxidation in order to obtain novel synthons for asymmetric synthesis (yields given in mg/l). -(FINN, K. J.; ROCHON, L.; HUDLICKY*, T.; Tetrahedron: Asymmetry 16 (2005) 21, 3606-3613; Dep. Chem., Brock Univ., St. Catharines, Ont. L2S 3A1, Can.; Eng.) -Nuesgen 14-044
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