6-Demethoxythebaine and its conversion to analgesics of the 6,14-ethenomorphinan type

Abstract
The 6-demethoxy analog of thebaine was easily prepared from codeine via isocodeine and its sulfenate ester. This diene readily undergoes reaction with vinyl ketones to afford Diels-Alder adducts of the 6,14-ethenomorphinan type. Further reactions afford the epimeric 19(R)- and 19(S)-butyl-6-demethoxy-7.alpha.-orvinols. Pharmacological testing [in rats] shows the R diastereomer to be highly analgesic and the S diastereomer to be a much less potent agonist, with similar potencies and relationships as found in the corresponding oripavine series. Any H bonding between the 6-methoxyl group and the tertiary alcohol can be eliminated as contributory to either the activity of, or difference between, the epimeric orvinols.