22151-78-6Relevant academic research and scientific papers
Improved synthesis of buprenorphine from thebaine and/or oripavine via palladium-catalyzed N-demethylation/acylation and/or concomitant O-demethylation
MacHara, Ales,Werner, Lukas,Endoma-Arias, Mary Ann,Cox, D. Phillip,Hudlicky, Tomas
experimental part, p. 613 - 626 (2012/05/20)
An improved preparation of buprenorphine via palladium-catalyzed N-demethylation/acylation is reported. Three routes were investigated and compared in overall yield. The first involved N-demethylation/acylation of an advanced intermediate obtained from thebaine followed by hydrolysis of the N-acetamide and alkylation with cyclopropylmethyl bromide and/or reduction of the N-acetyl group with the Schwartz reagent followed by N-alkylation. The second route employed cyclopropylcarboxylic acid anhydride in the N-demethylation/acylation protocol and subsequent reduction of the cyclopropylcarboxamide by either lithium aluminum hydride or under hydrosilylation conditions. Both of these routes originated in thebaine and therefore required O-demethylation as a final step. The third route employed an N-demethylation/acylation sequence starting from oripavine rather than thebaine, thus avoiding the O-demethylation. The routes are compared for overall efficiency and experimental and spectral data are provided for all new compounds. Copyright
MICROBIAL N- AND O-DEMETHYLATION OF A THEBAINE DERIVATIVE
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Page/Page column 10; 11, (2008/06/13)
The invention provides a process for the N-demethylation or the N- and O-demethylation of a thebaine derivative which process comprises fermenting the derivative with a biocatalyst selected from the filamentous fungi from Cunninghamella dalmatica NRRL 1394, Cunninghamella echinulata NRRL 1387, Cunninghamella echinulata NRRL 1384, Cunninghamella echinulata ATCC 36190, Cunninghamella echinulata ATCC 11585a, Cunninghamella echinulata ATCC 9244, Cunninghamella polymorpha NRRL 1395, or Rhizopus nigricans Z5/1in a basal fermentation medium at a temperature of at least 25°C and not more than 34°C, for a period of time of at least 3 days.
