125653-67-0Relevant articles and documents
Exploration of the biocatalytic potential of a halohydrin dehalogenase using chromogenic substrates
Lutje Spelberg, Jeffrey H.,Tang, Lixia,Van Gelder, Marc,Kellogg, Richard M.,Janssen, Dick B.
, p. 1083 - 1089 (2002)
Halohydrin dehalogenases are bacterial enzymes that catalyse the reversible formation of epoxides from vicinal halohydrins. A spectrophotometric assay for halohydrin dehalogenases based on the absorption difference between the halohydrin para-nitro-2-bromo-1-phenylethanol and the epoxide para-nitrostyrene oxide was developed. The enantioselectivity of ring-closure reactions catalysed by three different halohydrin dehalogenases could be estimated from the shape of progress curves. Evaluation of ring-opening reactions catalysed by halohydrin dehalogenase from Agrobacterium radiobacter AD1 established that, in addition to Cl- and Br-, nucleophiles such as N3-, CN- and NO2- are also accepted for the ring opening of para-nitrostyrene oxide. The ring-opening reactions with these nucleophiles resulted in highly enantioselective kinetic resolutions, which expands the scope of synthetically valuable conversions catalysed by a halohydrin dehalogenase.
Synthesis of β-adrenergic blockers (R)-(-)-nifenalol and (S)-(+)-sotalol via a highly efficient resolution of a bromohydrin precursor
Kapoor, Munish,Anand, Naveen,Ahmad, Khursheed,Koul, Surrinder,Chimni, Swapandeep S.,Taneja, Subhash C.,Qazi, Ghulam N.
, p. 717 - 725 (2005)
(R)- and (S)-2-bromo-1-(4-nitrophenyl)ethanol are precursors of important β-adrenergic receptor blocking drugs (R)-nifenalol and (S)-sotalol, respectively. Both were obtained in enantiomeric pure forms via a single highly efficient enzymatic transesterification reaction of (±)-2-bromo-1-(4- nitrophenyl)ethanol using immobilized lipase PS-C-II (E >1000; concn 200 g/L), while PS lipase completely failed to react. On the other hand, the hydrolytic method also produced enantiorich precursors though relatively less efficient (PS-C-II, E = 5.1). Out of all the approaches employed the transesterification method proved to be the most efficient.
Integration of multiple active sites on large-pore mesoporous silica for enantioselective tandem reactions
Xia, Xuelin,Meng, Jingjing,Wu, Hanxin,Cheng, Tanyu,Liu, Guohua
supporting information, p. 1638 - 1641 (2017/02/10)
Facile construction of a multifunctional heterogeneous catalyst through the assembly of Au/carbene and chiral ruthenium/diamine dual complexes in large-pore mesoporous silica was developed. This enables an efficient one-pot hydration-asymmetric transfer hydrogenation enantioselective tandem reaction of haloalkynes, affording chiral halohydrins with up to 99% enantioselectivity. Combined multifunctionalities, such as substrate-promoted silanol-functionality, BF4? anion-bonding gold/carbene and covalent-bonding chiral ruthenium/diamine active centers, contributed cooperatively to the catalytic performance.
Surfactant-accelerated asymmetric transfer hydrogenation with recyclable water-soluble catalyst in aqueous media
Li, Jiahong,Li, Xuefeng,Ma, Yaping,Wu, Jiashou,Wang, Fei,Xiang, Jing,Zhu, Jin,Wang, Qiwei,Deng, Jingen
, p. 1825 - 1834 (2013/03/14)
Water-soluble ligands (R,R)-2 were successfully prepared, in which the bis-meta-sulphonated ligand was definitely detected as the major product. The corresponding transition-metal complexes containing the ligands displayed excellent catalytic performance in asymmetric transfer hydrogenation (ATH) of aromatic ketones. Especially, the aromatic ketones with a bromine group in the α position could be smoothly reduced to the expected alcohol, keeping the bromine group intact with excellent enantioselectivities (up to 96% ee). The catalyst could be reused at least 21 times without erosion of the enantioselectivity in high conversion. Moreover, it was found that cationic surfactant and proper pH values were necessary for the maintenance of high reactivity.
