Synthesis and purification of 3ß-acetoxy-17-(3-pyridyl)androsta-5,16-diene
Publication Date: 2014-Jul-09
The IP.com Prior Art Database
Disclosed herein are a reaction to prepare vinyl triflate compounds and a method for purification of 3ß-acetoxy-17-(3-pyridyl)androsta-5,16-diene.
A common method to prepare vinyl triflate compounds involves the interaction of enolizable ketones with triflic anhydride in the presence of a base. The reaction can be carried out in heterogeneous reaction conditions in the presence of bases such as NaHCO3, Na2CO3 or KOAc with good conversion of the ketone substrate according to the scheme below. Those reaction are described, for examples in publications IPCOM000233230D and IPCOM000225574D.
The above described reaction can be done also in the presence of a well-defined amount of water (1 -10% w./w. vs. base):
A mixture of compound A and a base (e.g. NaHCO3, Na2CO3, KOAc) in dichloromethane (“DCM”) and water (1-10% vs. base) was stirred at room temperature for 30 minutes. Upon cooling below 0 °C, triflic anhydride (1.0-2.0 eq.) was added. The reaction mixture was kept under stirring below 0°C for 5-15 hours and then quenched with an organic base. The organic phase was concentrated to residue to afford compound B as a crude material.
The obtained compound B can be used to prepare 3ß-acetoxy-17-(3-pyridyl)androsta-5,16-diene, by any method known in the art, for example US patent 5,604,213. The obtained product may con...