Hoffmann-la Roche Inc.

Marquard Imfeld

Henri Ramuz

Emil A Broger

Jean-Claude Muller

Erich Widmer

Yvo Crameri

Peter Vogt

Francedillaois Montavon

A process for the asymmetric hydrogenation of a compound of the formula ##STR1## wherein each R, independently, is alkyl, arylmethyl, aryl, alkoxy, arylmethoxy or aryloxy or both R's, taken together, are methylene, ethylene or 1,2-phenylene and n is 1,2 or 3, or of a salt thereof to a compound of the formula ##STR2## in the form of an (S) or (R) enantiomer, wherein R and n have the significances given above, using an optically active ruthenium-diphosphine complex as catalyst, is described. The preparation of the compounds of formula II, as well as the compounds of formula II, which form a further object of the invention, are also described.

Asymmetric hydrogenation process using ruthenium-diphosphine complexe

The present invention is directed to novel hydroquinone derivatives which are useful as intermediates for the manufacture of (R,R,R)-.alpha.-tocopherol (natural vitamin E) as well as of racemic .alpha.-tocopherol. The invention is also directed to a process for the preparation of the hydroquinone derivatives of the invention.

Hydroquinone derivatives useful in the production of vitamin E

Novel pyrimidinedicarbamates of the formula ##STR1## wherein R is lower alkyl or (lower alkyloxy)-(lower alkyl) and X is a leaving group, can be manufactured by carbamoylating the corresponding free diamines. They are valuable intermediates and can be used, for example, for the manufacture of corresponding oxadiazolopyrimidines of the formula ##STR2## and pharmaceutically acceptable salts thereof. The latter have valuable long-lasting vasodilating and/or bloodpressure lowering properties and are accordingly suitable especially for the treatment of vascular-conditioned hypertensions or as vasodilators in the case of peripheral blood supply disorders.

Dicarbamates

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Binningen, Switzerland

Marquard Imfeld