Preparation of cis-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-di benzo[b,d]pyran-9-ones and intermediates therefor
AssigneeEli Lilly and Company
InventorsWilliam B. Blanchard, Charles W. Ryan
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Abstract
Reaction of a 5-substituted resorcinol with a ketal of 4-(1-hydroxy-1-methylethyl)-3-cyclohexen-1-one in the presence of a suitable catalyst effects condensation to provide substantially exclusively a cis-1-hydroxy-3-substituted-6-6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibe nzo[b,d]pyran-9-one.
Claims7
A process for preparing a hexyldrodibenzopyranone of the formula ##STR4## 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 cis to one another, comprising reacting a 5-substituted resorcinol of the formula ##STR5## wherein R has the above-defining meaning, and a 4-(1-hydroxy-1-methylethyl)-3-cyclohexenone ketal of the formula ##STR6## wherein:
- n is O or 1, R'and R" independently are hydrogen, methyl or ethyl;
- in the presence of a catalyst selected from the group consisting of boron tribromide, boron trifluoride, and stannic chloride, in an organic solvent at a temperature in the range of from about -20.degree. C. to about 100.degree. C., for a period of time of from about 0.5 to about 8 hours.
Dependencies are inferred from the claim text.