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US 4,054,583 AGranted
Process for converting 2,7-dihydroxy-5-isopropylidene-9-substituted-2,6-methano-3,4,5,6-tetrahy dro-2H-1-benzoxocin to trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H- dibenzo(b,d)pyran-9-one
AssigneeEli Lilly and Company
InventorsWilliam B. Blanchard, Charles W. Ryan
Life of this patent
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Abstract
Reaction of an aluminum halide with a 2,7-dihydroxy-5-isopropylidene-9-substituted-2,6-methano-3,4,5,6-tetrahydr o-2H-1-benzoxocin in an organic solvent effects cleavage of the pyran ring system with concomitant recyclization to provide exclusively a trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-di benzo[b,d]pyran-9-one.
Claims7
A process for preparing a compound of the formula ##STR3## 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 a 2,7-dihydroxy-5-isopropylidene-9-substituted-2,6-methano-3,4,5,6-tetrahydr o-2H-1-benzoxocin of the formula ##STR4## wherein R has the above-defined meaning, with from about 2 to about 6 molar equivalents of an aluminum halide selected from aluminum chloride and aluminum bromide, in a halogenated hydrocarbon or aromatic solvent, at a temperature ranging from about -20.degree. C. to about 100.degree. C.
Dependencies are inferred from the claim text.