Hoffmann-la Roche Inc.

Kurt Steiner

Manfred W Breuninger

Helmut Tiltscher

Siegfried Schmitt

Herwig Ertel

Manfred Froom

Karl-Heinz Bender

A process for the manufacture of 4H-imidazo�1,5-a!�1,4!benzodiazepine derivatives of formula I ##STR1## wherein R.sup.1 is phenyl or mono- or disubstituted phenyl;

Process for the manufacture of 4H-imidazo�1,5-A!�1,4!benzodiazepines

A process is described for the manufacture of .beta.-ionone by the sulphuric acid-catalyzed cyclization of pseudoionone in a two-phase solvent system comprising concentrated sulphuric acid and a second solvent essentially immiscible with water, which process comprises using carbon dioxide liquefied under pressure as the second solvent. This process is carried out, inter alia, under a pressure of about 50 bar to about 150 bar and at temperatures from about -15.degree. C. to about +15.degree. C. prior to the subsequent stopping (quenching) of the cyclization reaction. The process in accordance with the invention is preferably carried out continuously and is an important intermediate stage in the synthesis of vitamin A.

Method for the production of .beta.-ionone from pseudoionone

Improved, selective hydrogenation of alpha, beta-unsaturated aldehydes to alpha,beta-unsaturated alcohols utilizing a platinum-cobalt catalyst.

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Starrkirch, Switzerland

Kurt Steiner