Roussel Uclaf

Aventis Pharma S.a.

Denis Prat

Jean-Yves Godard

Philippe Mackiewicz

Christian Richard

Francoise Benedetti

Jean Buendia

Michel Vivat

Francois Nique

Christian Wehrey

Christian Masson

Veronique Crocq

Christian Moratille

Lahlou Nait-Bouda

Alain Mazurie

Françoise Benedetti

The subject of the invention is a method for preparing compounds of general formula (I): in which A, Z, Rare as defined in the description, and the intermediate compounds for carrying out this method.

Method and intermediates for preparing 19-norsteroid compounds

A process for the preparation of compounds of formula (I) 

Method for preparing oestrogen derivatives

A compound of the formula ##STR1## wherein R is hydrogen or an ester remainder, X is hydrogen or fluorine and Y combined with the doted lines represents ##STR2## or X is hydrogen and and Y combined with the dotted lines is ##STR3## and R.sub.1 is the remainder of an enol ether or ester.

Intermediates for the preparation of 6.alpha., 9.alpha.-difluoro steroids

A process for the preparation of 6.alpha.,9.alpha.-difluoro steroids of the formula ##STR1## wherein R is hydrogen or an ester remainder.

Preparation of 6.alpha., 9.alpha.-difluoro steroids

A process for the preparation of a compound of the formula ##STR1## wherein R.sub.1 is alkyl of 1 to 3 carbon atoms, R.sub.2 is alkyl of 1 to 12 carbon atoms, R.sub.3 is alkyl of 1 to 4 carbon atoms comprising reacting a compound of the formula ##STR2## wherein R.sub.4 is a remainder of an easily cleavable ether, K is a protected ketone function in the form of ketal, thioketal or mixed ketal and R.sub.1 has the above definition with a magnesium organic compound reagent of the formula

Process for the preparation of 20-keto-21 alpha-01-steroids

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Pantin, France

Denis Prat