Stereoselective preparation of hexahydro dibenzopyranones and intermediates therefor
Patent 4102902 Issued on July 25, 1978. Estimated Expiration Date: 
November 10, 1996. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 10, 1996. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3856820 3856821 3856822 InventorsAssigneeApplicationNo. 05/740502 filed on 11/10/1976US Classes:549/391, Plural chalcogens bonded directly to the tricyclo ring system560/256, Polycyclo-alicyclic ring system in alcohol moiety568/327, Bicyclo ring system568/329Alicyclic ring containingExaminersPrimary: Chan, NickyAttorney, Agent or FirmInternational ClassesC07D 311/00 (20060101)C07D 311/80 (20060101) AbstractAn optically active 4-(4-substituted-2,6-dihydroxyphenyl)-6,6-dimethyl-2-norpinanone is reacted with a protonic acid to provide an optical isomer of a cis-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibe nzo[b,d]pyran-9-one. Reaction of said norpinanone with a Lewis acid provides an optical isomer of trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-di benzo[b,d]pyran-9-one. The optically active norpinanones are prepared by reaction of a 5-substituted-resorcinol with an optically active 6,6-dimethyl-2,4-diacetoxy-2-norpinene or an optically active 6,6-dimethyl-2,2-diacetoxy-3-norpinene, which compounds are derived from optically active ଲ-pinenes.Other References
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