Stereochemical Studies in the Morphine Series. The Relative Configuration at Carbons Five and Six

The Preparation of Some Dihydro Ketones in the Morphine Series by Oppenauer Oxidation

“…For the carbon-8 epimers, the hydroxyl of pseudocodeine would be trans to the 9,14 carbon-carbon bond and that of allopseudocodeine would be cis. These deductions for the codeine-isocodeine pair are confirmed by recent independent findings on their stereochemistry (11).…”

“…Dihydrocodeine (IV). Codeine was hydrogenated (11) in dilute acetic acid using a palladium on barium sulfate catalyst to give a 93% yield of dihydrocodeine, m.p. 109-111°.…”

Chemistry of Guareschi Imides I

“…Selective reduction was also attempted under the experimental conditions of increasing reflux periods up to 24 hours and/or decomposing the hydride complex with 10% sulfuric acid (10). In addition, increasing amounts of lithium aluminum hydride.…”

Reactions of Alkoxides With Certain Hydrogenated Alkaloids of the Morphine Series

“…On the basis of a degradation study Rapoport, et al (7) reached the opposite conclusion concerning the configuration of these epimers. Their additional finding (1) that dihydrocodeine was easily oxidized in an Oppenauer-type reaction employing potassium íerí-butoxide as catalyst whereas dihydroisocodeine was relative inert was interpreted as offering confirmation of the view that dihydroisocodeine has the trans structure.…”

“…[E.g., dihydroisocodeine was previously prepared by the sequences: codeine -» chlorocodide (8) -> isocodeine (7) -> dihydroisocodeine in ca. 6-22% over-all yield (7); or, codeine -» bromocodide -» isocodeine -> dihydroisocodeine (7) in 35% over-all yield]. Furthermore it will allow assignment of definite configuration, at the carbinol carbon, to isomers presently of unknown configuration, e.g., the two dihydrothebainols (10).…”