Synthetic Amphoteric Polypeptide. I. Syntheses and Some Properties of Linear Amphoteric Polypeptides
作者:Heimei Yuki、Shumpei Sakakibara、Hisaya Tani
DOI:10.1246/bcsj.29.654
日期:1956.6
1. Two linear highmolecular amphoteric polypeptides were synthesized. 2. The pH-dependences of viscosity and optical rotation were measured. Some of these properties resembled that of vinyl polyampholytes and some proteins.
Scale-Up Studies for the Asymmetric Juliá–Colonna Epoxidation Reaction
作者:Arne Gerlach、Thomas Geller
DOI:10.1002/adsc.200404079
日期:2004.8
The asymmetricJuliá–Colonnaepoxidationreaction under triphasic/PTC conditions has been successfully scaled-up to a one-hundred gram substrate level providing the corresponding epoxy ketone with high optical purity (up to 97% ee) and in good yield (75–78%). The amount of polyamino acid catalyst could be reduced leading to a simplified reaction work-up. In order to minimise the overall reaction time
Novel conditions for the Juliá–Colonna epoxidation reaction providing efficient access to chiral, nonracemic epoxides
作者:Thomas Geller、Arne Gerlach、Christa M. Krüger、H.-Christian Militzer
DOI:10.1016/j.tetlet.2004.04.188
日期:2004.6
The addition of a phase-transfer catalyst significantly accelerates the Juliá–Colonnaepoxidationreaction yielding chiral, nonracemic epoxy ketones. Furthermore, a reliable procedure for the preparation of highly active poly-l-leucine catalyst is reported.
[EN] PROCESS FOR THE PREPARATION OF N-CARBOXYANHYDRIDES<br/>[FR] PROCEDE DE PREPARATION DE N-CARBOXYANHYDRIDES
申请人:BIOCON LTD
公开号:WO2006027788A1
公开(公告)日:2006-03-16
The invention relates to a process for the preparation of N-carboxyanhydrides by reaction of the corresponding amino acid with phosgene, diphosgene and/or triphosgene in a solvent medium, characterized in that the reaction is a least partially carried out in the presence of an unsaturated organic compound which has one or more ethylenic double bonds. The N-carboxyanhydrides are thus obtained with better yields and an improved purity.