Abstract: A process for the preparation of a compound of formula (IIa) is described where A is a silyl protecting group, in high diastereoisomeric purity and in crystalline form, comprising the crystallization of a mixture of the compound of formula (IIa) and its isomer of formula (IIb), where A is a silyl protecting group, from an ethereal solvent. The invention also provides a process for preparing Estetrol of formula (I) in high diastereoisomeric purity, comprising the use of the compound of formula (IIa), in a crystalline form, as a starting material.

Abstract: The invention relates to a process for the preparation of Drospirenone in high yields and purity starting from a compound of formula 2 wherein R is a hydroxyl protective group as defined in the claims, through a sequence of oxidation, deprotection, lactonization and water elimination steps, and wherein the steps of oxidation and lactonization are performed with 1,3,5-trichloro1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (trichloroisocyanuric acid, TCCA) or 1,3-dichloro-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (dichloroisocyanuric acid, DCCA) or an alkaline metal salt thereof such as the sodium salt dihydrate (DCCA sodium salt) or 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (IBX). New synthetic intermediates useful for the synthesis of Drospirenone are disclosed, too.

Abstract: The invention relates to a process for the preparation of Drospirenone in high yields and purity starting from a compound of formula 2 wherein R is a hydroxyl protective group as defined in the claims, through a sequence of oxidation, deprotection, lactonization and water elimination steps, and wherein the steps of oxidation and lactonization are performed with 1,3,5-trichloro1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (trichloroisocyanuric acid, TCCA) or 1,3-dichloro-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (dichloroisocyanuric acid, DCCA) or an alkaline metal salt thereof such as the sodium salt dihydrate (DCCA sodium salt) or 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (IBX). New synthetic intermediates useful for the synthesis of Drospirenone are disclosed, too.