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US 4,067,906 AGranted
Novel process for the synthesis of tricyclo[6.2.2.0.sup.3,8 ]dodecane derivatives
AssigneeGivaudan SA
InventorsRobert F. Tavares, Elliot Katten
Life of this patent
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Abstract
A novel process for the preparation of tricyclo[6.2.2.0.sup.3,8 ]dodecane derivatives is presented. This novel process is applied to the synthesis of the odorant 4-acetyl-1,7,7-trimethyltricyclo[6.2.2.0.sup.3,8 ]-3-dodecene, also known as 4-aceto-6,8a-ethano-1,1,6-trimethyl-1,2,3,5,6,7,8,8a-octahydronaphthalene.
Claims6
The process for the preparation of 1,7,7-trimethyltricyclo[6.2.2.0.sup.3,8 ]dodec-9-en-4-one from 4-methyl-4-p-tolylpentanoic acid which comprises:
- a. 1,4-hydrogenating the aromatic ring of the 4-methyl-4-p-tolylpentanoic acid via a Birch reduction to 4-methyl-4(4-methyl-1,4-cyclohexadien-1-yl)pentanoic acid;
- b. isomerizing the 4-methyl-4(4-methyl-1,4-cyclohexadien-1-yl)pentanoic acid to 4-methyl-4(4-methyl-1,3-cyclohexadien-1-yl)pentanoic acid in the presence of a base;
- c. reacting the 4-methyl-4(4-methyl-1,3-cyclohexadien-1-yl)pentanoic acid with vinyl lithium to form the intermediate 6-methyl-6(4-methyl-1,3-cyclohexadien-1-yl)hepten-3-one which is converted via an internal Diels-Alder reaction to form the 1,7,7-trimethyltricyclo[6.2.2.0.sup.3,8 ]dodec-9-en-4-one.
Dependencies are inferred from the claim text.