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US 4,054,582 AGranted
Process for converting cis-hexahydrodibenzo[b,d]pyran-9-ones to trans-hexahydrodibenzo[b,d]-pyran-9-ones
AssigneeEli Lilly and Company
InventorsWilliam B. Blanchard, Charles W. Ryan
Life of this patent
Estimating the term…
Abstract
Reaction of cis-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibe nzo[b,d]pyran-9-ones with an aluminum halide in an unreactive organic solvent effects complete epimerization to provide the corresponding trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-di benzo[b,d]pyran-9-one.
Claims5
A process for preparing a 6a,10,a-trans-hexahydrodibenzo[b,d]pyran-9-one of the general formula ##STR2## wherein:
- R is C.sub.5 -C.sub.10 alkyl, C.sub.5 -C.sub.10 alkenyl, C.sub.5 -C.sub.8 cycloalkyl, or C.sub.5 -C.sub.8 cycloalkenyl;
- and wherein the hydrogen atoms attached at the 6a and 10a positions are oriented trans to one another;
- comprising reacting the corresponding 6a,10a-cis-hexahydrodibenzo[b,d]pyran-9-one with an aluminum halide selected from the group consisting of aluminum chloride and aluminum bromide, in an unreactive organic solvent, at a temperature ranging from about -80.degree. to about 100.degree. C., for a period of time ranging from about 10 minutes to about 6 hours.
Dependencies are inferred from the claim text.