Bayer Aktiengesellschaft

Arthur Haaf

Michael Preiss

Paul Naab

Rudolf Zerbes

Wolfgang Koebernick

Werner Teller

Ulrich Schorsch

Known quinolone carboxylic acid derivatives of the formula ##STR1## are treated so as to become readily administrable parenterally, the treatment comprising dissolving the active compound using an acid, allowing the solution to stand for about 0.15 to 150 hours at a temperature from room temperature to the boiling point of the solution, filtering the solution, precipitating the active compound from the solution using a basic reagent, and converting the precipitated active compound into a form which can be administered parenterally.

Process for the preparation of quinolonecarboxylic acids which can be

In the preparation of a 1,4-dihydropyridine of the formula ##STR1## in which R is a phenyl radical which is optionally substituted once or twice by nitro and/or chlorine,

Process for the preparation of 1,4-dihydropyridinedicarboxylic esters

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Wuppertal, Germany

Arthur Haaf