Miltenyi Biotec, Gmbh

Cognis Deutschland Gmbh

Dirk Merkel

Stefan Miltenyi

Thomas Markert

Jürgen Schulz

Hans-Josef Altenbach

Daniel Michalek

A method and associated device for enrichment of Ne&#xe9;l-magnetic particles from a dispersion of Brown-magnetic particles and Ne&#xe9;l-magnetic particles. The device and method use ferromagnetic separation particles having a mean diameter of 100 to 250 &#x3bc;m located in a alternating magnetic field. The ferromagnetic separation particles have a magnetically and chemically inert coating.

Device and method for separation of Ne&#xe9;l- and brown-magnetic particles

The present invention relates to a method for preparing optically active 5-methtyl-2-(1-methtyl-butyl)-5-propyl-1,3-dioxan, wherein said method comprises the following steps: converting lactic acid methylic ester into the corresponding N,N-disubstituted amid (aminolysis with piperidine and/or pyrrolidine); protecting its free OH function by a reaction with ethylvinylether in the presence of p-pyridiniumtosylate as a catalyst; submitting the N-pentamethylen- or N-tetramethylenlactamide thus obtained to a Grignard reaction in a conventional way so as to produce the corresponding &agr;, &bgr;-unsaturated ketone; further separating in a conventional way (e.g. agitation with acetic acid) the protection group introduced during the second step; acetalating in a conventional way the ketone function (e.g. by reaction with 2-methyl-2-propyl-1,3-propanediol); mesylating the free OH function by reaction with methansulfonic acid chloride in pyridine; submitting the intermediate thus obtained to a reducing 1,2-transposition in the presence of trimethylammonium and diisobutylaluminum hydride while maintaining the sterochemistry; and converting by catalytic hydrogenation the dehydro compound thus abtained into optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan. The optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan of the present invention exhibits a remarkable scent profile as well as a high scent intensity and may be used as perfume.

Method for preparing optically active 5-methyl-2-(1-methyl-butyl)-5-propyl-1,3-dioxan

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Solingen, Germany

Dirk Merkel