91603-11-1Relevant articles and documents
A chiral dimethyl cyclopropanecarboxylic preparation method of the formamide
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Paragraph 0025; 0037; 0041; 0045; 0049; 0053; 0054; 0055, (2018/11/03)
The invention discloses a preparation method of chiral dimethyl cyclopropyl carboxamide. The method comprises a step of asymmetric cyclopropyl alkylation and a step of catalytic amidation of cyclopropyl formic ether, wherein in the step of asymmetric cyclopropyl alkylation, a cyclopropyl alkylation reaction is carried out on ethyl diazoacetate and isobutene under the catalysis of a chiral ligand complex of a cuprous salt so as to obtain (S)-dimethyl cyclopropyl formate; and in the step of catalytic amidation of cyclopropyl formic ether, an ammonolysis reaction is carried out on the (S)-dimethyl cyclopropyl formate by one step so as to directly obtain (S)-2,2-dimethyl cyclopropyl carboxamide, and refining the carboxamide with an alcohol so as to obtain the chiral dimethyl cyclopropyl carboxamide with chemical purity being greater than 99.5% and an e.e. value being greater than 99.5%. Thus, the method used for synthesizing the (S)-2,2-dimethyl cyclopropyl carboxamide is environment-friendly, simple, rapid and efficient.
Substrate channel evolution of an esterase for the synthesis of cilastatin
Luan, Zheng-Jiao,Li, Fu-Long,Dou, Shuai,Chen, Qi,Kong, Xu-Dong,Zhou, Jiahai,Yu, Hui-Lei,Xu, Jian-He
, p. 2622 - 2629 (2015/05/13)
The esterase RhEst1 from Rhodococcus sp. ECU1013 has been reported for the enantioselective hydrolysis of ethyl (S)-(+)-2,2-dimethylcyclopropane carboxylate, producing the building block of cilastatin. In this work, error-prone PCR and site-directed saturation mutagenesis were applied to RhEst1 for activity improvement, with the pH-indicator assay as a high-throughput screening method. As a result, RhEst1A147I/V148F/G254A, with mutations surrounding the substrate access channel, showed a 5-fold increase in its specific activity compared with the native enzyme, as well as a 4-fold increase in protein solubility. Combined with the determination of protein structures and computational analysis, this work shows that the amino acids around the substrate channel play a more important role in the activity evolution of RhEst1 than those in the active site. This journal is
Remarkable efficiency improvement in the preparation of insoluble polymer-bound (IPB) enantioselective catalytic systems by the use of silicone chemistry
Mandoli, Alessandro,Lessi, Marco,Pini, Dario,Evangelisti, Claudio,Salvadori, Piero
supporting information; experimental part, p. 375 - 379 (2009/04/11)
The use of platinum-catalyzed hydrosilylation chemistry of silicones greatly simplifies the preparation of bis-oxazoline (box) ligands covalently bound to an insoluble polymeric support. The use of such immobilized chiral ligands in different copper-catalyzed asymmetric transformations (carbonyl-ene, Mukaiyama aldol and olefin cyclopropanation reactions) allows the attainment of high levels of enantioselectivity (91-99% ee).
Siliceous mesocellular foam-supported aza(bisoxazoline)-copper catalysts
Lim, Jaehong,Riduan, Siti Nurhanna,Su, Seong Lee,Ying, Jackie Y.
scheme or table, p. 1295 - 1308 (2009/06/05)
Aza(bisoxazoline) was easily immobilized on siliceous mesocellular foam (MCF) in a systematic approach. It was found that silanol precapping, linker group flexibility, ligand loading, and silanol postcapping were important factors to consider in optimizing silica-supported aza(bisoxazoline) catalysts. The optimized MCF-supported aza(bisoxazoline)-copper catalyst offered the same enantioselectivity as its homogeneous counterpart, and excellent recyclability. The heterogenized catalyst showed a much higher chemoselectivity in a short reaction time. The heterogenized aza(bisoxazoline)-copper(I) catalyst was successfully applied to a circulating flow-type packed bed reactor with excellent productivity and enantioselectivity. The circulating flow-type reactor was found to be very useful for gas-generating catalytic reactions such as cyclopropanation reaction.
Improved enantioselectivity of immobilized chiral bisoxazolines by partial precapping of the siliceous mesocellular foam support with trimethylsilyl groups
Lee, Su Seong,Hadinoto, Sukandar,Ying, Jackie Y.
, p. 1248 - 1254 (2007/10/03)
Siliceous mesocellular foams (MCF) were partially surface-modified with trimethylsilyl (TMS) groups prior to the immobilization of chiral tert-butylbisoxazolines. The resulting MCF-supported bisoxazoline-Cu(I) catalyst showed superior enantioselectivity (
A reusable, insoluble polymer-bound bis(oxazoline) (IPB-box) for highly enantioselective heterogeneous cyclopropanation reactions
Mandoli, Alessandro,Orlandi, Simonetta,Fini, Dario,Salvadori, Piero
, p. 2466 - 2467 (2007/10/03)
A reusable, insoluble polystyrene-supported bis(oxazoline) was developed, affording e.e.s > 90% in the heterogeneous enantioselective cyclopropanation of styrene and 1,1-disubstituted alkenes with ethyl diazoacetate.
