26511-17-1Relevant academic research and scientific papers
Synthetic studies on d-biotin. Part 7: A practical asymmetric total synthesis of d-biotin via enantioselective reduction of meso-cyclic imide catalyzed by oxazborolidine
Chen, Fen-Er,Dai, Hui-Fang,Kuang, Yun-Yan,Jia, Hui-Qing
, p. 3667 - 3672 (2003)
A novel and convenient method for the stereoselective synthesis of d-biotin 1 starting from the commercially available cis-1,3-dibenzyl-2- imidazolidone-4,5-dicarboxylic acid 2 has been developed. The key features of this synthesis include the enantioselective reduction of a meso-cyclic imide, mediated by a chiral oxazborolidine catalyst, derived from (1S,2S)-(+)-threo-1- (4-nitrophenyl)-2-amino-1,3-propanediol and the direct introduction of a C 5 side chain to the (3aS,6aR)-thiolactone through a modified di-Grignard reaction. Enantioselectivities of 98% in the oxazborolidine- catalyzed asymmetric reduction process have been achieved.
Synthetic studies on d-biotin, part 9.1) An improved asymmetric synthetic route to d-biotin via Hoffmann-Roche lactone-thiolactone approach
Chen, Fen-Er,Jia, Hui-Qing,Chen, Xu-Xiang,Dai, Hui-Fang,Xie, Bin,Kuang, Yun-Yan,Zhao, Jian-Feng
, p. 743 - 746 (2007/10/03)
An efficient and highly stereoselective total synthesis of d-biotin has been achieved starting from cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid (2) with an overall yield of 33%. Polymer-supported oxazaborolidine- catalyzed asymmetric reduction of meso-cyclic imide 4 constitutes the key synthetic step in introducing stereogenic centers into the d-biotin molecule.
Synthetic Studies on d-Biotin, Part 6:1 An Expeditious and Enantiocontrolled Approach to the Total Synthesis of d-Biotin via a Polymer-Supported Chiral Oxazaborolidine-Catalyzed Reduction of meso-Cyclic Imide Strategy
Chen, Fen-Er,Yuan, Jian-Li,Dai, Hui-Fang,Kuang, Yun-Yan,Chu, Yong
, p. 2155 - 2160 (2007/10/03)
An efficient and highly enantioselective synthesis of d-biotin from the known cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid (5) was accomplished in 48% overall yield. The key reactions in the sequence involve the catalytic enantioselective reduction of meso-cyclic imide 6 using polymer-supported chiral oxazoborolidine, derived from (S)-α,α -diphenylprolinol and polymer-bound sulfonyl chloride, and the installation of the C5 side chain at C4 in the thiolactone 9 via a Ni/C-catalyzed Fukuyama coupling reaction.
Synthesis of Pyrroloimidazoles. A New Fluorescent Heterocyclic System.
Casteel, Dee Ann,Leonard, Nelson J.
, p. 2450 - 2456 (2007/10/02)
Pyrroloimidazoles (9) "stretched-up" pyrimidine analogues, have been prepared by a two step procedure from the corresponding pyrroloimidazolines (5).The new heterocyclic system displays exceptional fluorescence properties.Large Stokes shifts
