Basf Aktiengesellschaft

Rolf Lebkuecher

Walter Himmele

Dieter Lenke

Josef Gries

Marco Thyes

Horst Koenig

Karl-Heinz Ross

Christian Dudeck

Hans D Lehmann

Wolfgang Sauer

Johannes Kunze

6-(p-Acylaminophenyl)-4,5-dihydropyridaz-3-ones of the formula I ##STR1## where R.sup.1 is hydrogen or alkyl of 1 to 3 carbon atoms and R.sup.2, if R.sup.1 is hydrogen, is halogen-substituted alkyl of 3 to 6 carbon atoms or .beta.-haloethyl or, if R.sup.1 is alkyl of 1 to 3 carbon atoms, is halogen-substituted alkyl of 1 to 6 carbon atoms, their manufacture, and therapeutic agents which contain, as the active ingredient, a compound of the formula I, where R.sup.2 may also be halomethyl or .alpha.-haloethyl if R.sup.1 is hydrogen. These compounds may be used as anti-hypertensive agents and for the prophylaxis and therapy of thromboembolic disorders.

6-(p-Acylaminophenyl)-4,5-dihydropyridaz-3-ones and therapeutic agents

A process for the preparation of the sought-after scent 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one, and novel intermediates for the preparation of this compound. 2,5-Dimethyl-4-hydroxy-2,3-dihydrofuran-3-one is prepared by first epoxidizing hex-3-ene-2,5-diol in the liquid phase with hydrogen peroxide to give the novel compound 3,4-epoxy-hexane-2,5-diol, which at 40.degree.-280.degree. C. is converted, by means of a catalytic amount of an acid, to the novel compound 2,5-dimethyl-3,4-dihydroxy-tetrahydro-furan. The latter is dehydrogenated by means of oxygen over a silver catalyst or copper catalyst to give the nove compound 2,5-dimethyl-4-hydroxy-tetrahydrofuran-3-one, which is oxidized by means of bismuth oxide, in concentrated acetic acid solution, to give the desired compound 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one.

Preparation of 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one

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Ludwigshafen, Germany

Rolf Lebkuecher