Firmenich Sa

Cyril Mahaim

Roger L Snowden

Dana P Simmons

Karl-Heinrich Schulte-Elte

Wolfgang K Giersch

Edouard P Demole

Pierre-Alain Blanc

Koenraad Vanhessche

Jorge M Lem

Koenraad P Vanhessche

The present invention relates to the field of organic synthesis and more particularly to a new process for the preparation of an acetal derivative of an alkyl 3-oxo-2-(2-oxoethyl)-1-cyclopentaneacetate. The invention also relates to a method to use said acetal derivative to prepare intermediates useful for the preparation of perfuming ingredients.

Process for the preparation of cyclopentanone derivatives

Perhydro-5,5-8a-trimethyl-2-naphthalenone is prepared by acid cyclization of carboxylic esters of formula ##STR1## having a double bond in one of the positions indicated by the dotted lines and wherein symbol R designates a C.sub.1 -C.sub.6 alkyl radical, X stands for a monovalent radical of formula P(O)(OR.sup.1).sub.2 or C(O)R.sup.2, R.sup.1 represents a C.sub.1 -C.sub.6 alkyl group and R.sup.2 is either a linear or branched alkyl group or a substituted or unsubstituted phenyl radical, and wherein the wavy line represents a C--C bond of cis or trans configuration, or of formula ##STR2## wherein the wavy lines and symbol R are defined as above, and R.sup.0 represents a C.sub.3 -C.sub.6 alkyl radical, preferably branched, followed by basic decarboxylation of the obtained product.

Carboxylic esters for the preparation of a bicyclic decalin ketone

Process for the preparation of a bicyclic decalin ketone

3-Methyl-cyclopentadec-5-en-1-one and its cis- and transconfiguration isomers are useful as perfuming ingredients, for the preparation of perfuming compositions and perfumed articles to which they impart musky notes characteristic of nitro-musks.

Use of a cyclopentadecenone as perfuming ingredient

The compounds of the formula ##STR1## wherein R represents a 3,3-dimethyl-1-cyclopentyl or a 3,3-dimethyl-1-1cyclohexyl radical, R.sup.5 represents a saturated, linear or branched, C.sub.1 to C.sub.3 alkyl radical and, either R.sup.1 and R.sup.2 stand each for a hydrogen atom, R.sup.3 and/or R.sup.4 representing a methyl radical, or R.sup.3 and R.sup.4 represent each a hydrogen atom, R.sup.1 and/or R.sup.2 representing then a methyl radical, are novel compounds and useful perfuming ingredients, capable of imparting to the compositions into which they are incorporated odor notes of the musky-ambrette and fruity type. A process for the preparation of compounds (I) is disclosed.

Esters and their use in perfumery

The polyunsaturated compounds of formula ##STR1## having two conjugated double bonds in the endo- and exo- positions of the pentagonal cycle indicated by the dotted lines, and wherein symbols R.sup.1 and R.sup.2, when taken separately, represent respectively a. a linear or brached C.sub.1 to C.sub.4 alkyl radical and b. an hydrogen atom or a methyl radical, or, when taken together with the carbon atoms to which they are bonded form a polymethylenic cycle such as indicated by the dotted line, containing from 5 to 12 carbon atoms, and symbol R.sup.3 stands for an hydrogen atom or a methyl radical, n being an integer equal to 0 or 1, which are useful intermediate products for the preparation of odoriferous macrocyclic ketones, are prepared according to a process comprising a vapor phase cyclization of an enone of formula ##STR2## wherein the dotted line and the symbols n, R.sup.1, R.sup.2 and R.sup.3 are defined as above, effected by means of a thermal treatment of said enone in the presence of a cyclization catalyst consisting of an aluminum, silicium, titanium or zirconium oxide.

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Echichens, Switzerland

Cyril Mahaim