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: Described is a clamp of an external fixation device for the treatment of bone fractures, including a first locking unit designed to lock two bone screws, a second locking unit and a third locking unit each designed to lock a respective connecting bar.