Process for isolation of aspartyl dipeptide esters
申请人:G. D. Searle & Co.
公开号:US04017472A1
公开(公告)日:1977-04-12
The isolation of certain dipeptide esters, known to be potent sweetening agents, is achieved by selectively extracting, with a suitable alkanol in a heterogeneous system, an aqueous solution containing the dipeptide ester together with a variety of impurities.
Synthesis of novel chiral oxazoline ligands and application in the highly enantioselective diethylzinc addition to N-diphenylphosphinoylimines
作者:Gexin Yan、Yong Wu、Wenqing Lin、Xiaomei Zhang
DOI:10.1016/j.tetasy.2007.10.035
日期:2007.11
Two sets of novel chiraloxazoline ligands were designed and conveniently prepared from readily available l-aspartic acid and evaluated in enantioselective diethylzincaddition to N-diphenylphosphinoyl imines. In the presence of stoichiometric amounts of these ligands, high enantioselectivities (up to 95% ee) and yields (up to 85%) were achieved for several aromatic imines in toluene at room temperature