Indium tribromide-catalyzed chemoselective dithioacetalization of aldehydes in non-aqueous and aqueous media
作者:Marco Antonio Ceschi、Luciana de Araujo Felix、Clovis Peppe
DOI:10.1016/s0040-4039(00)01741-x
日期:2000.12
Indium tribromide efficiently catalyzes the chemoselective dithioacetalization of aldehydes in the presence of ketones in dichloromethane. The catalyst is also active in water, which can be reused, in the same pot, for several times without any decrease in the yield of reaction.
[EN] STEROID 6.7.BETA.-EPOXIDES AS CHEMICAL INTERMEDIATES<br/>[FR] BÊTA-ÉPOXYDES DE STÉROÏDES 6.7 COMME INTERMÉDIAIRES CHIMIQUES
申请人:NZP UK LTD
公开号:WO2017199039A1
公开(公告)日:2017-11-23
The invention relates to a process for preparing a compound of general formula (Ia): wherein R2, Y, R4 and R5 are as defined herein. The invention also relates to certain compounds perse. The compounds are intermediates in the synthesis of synthetic bile acids.
[EN] PROCESS AND INTERMEDIATES FOR THE 6,7-ALPHA-EPOXIDATION OF STEROID 4,6-DIENES<br/>[FR] PROCÉDÉ ET INTERMÉDIAIRES POUR L'ÉPOXYDATION 6,7-ALPHA DE 4,6-DIÈNES STÉROÏDES
申请人:NZP UK LTD
公开号:WO2017199036A1
公开(公告)日:2017-11-23
The invention relates to a process for preparing a compound of general formula (la): wherein R2, Y, R4and R5are as defined herein, wherein the epoxidation is conducted using an oxidant and methyltrioxorhenium as a catalyst (MeReO3). The invention also relates to certain compounds per se.The compounds are intermediates in the synthesis of synthetic bile acids.
Ceric ammonium nitrate as a convenient catalyst for chemoselective thioacetalisation
作者:Pijus Kumar Mandal、Subhas Chandra Roy
DOI:10.1016/0040-4020(95)00399-s
日期:1995.7
A new, mild and chemoselectiveprotection of aldehydes as 1,3-dithiolanes using ceric ammonium nitrate as a catalyst is described. High yields are obtained at room temperature even in the presence of ketones. While alicyclic ketones may also be protected at elevated temperature, aromatic and acyclic ketones remained uneffected.