10020-96-9Relevant articles and documents
The Oxidation of Benzaldehyde to Benzoic Acid Catalysed by Cyclo-, and its Implications for the Catalytic Assymmetric Addition of HCN to Aldehydes
Hogg, David J.P.,North, Michael,Stokoe, Robert B.,Teasdale, William G.
, p. 1553 - 1558 (1993)
Key Words: cyclo-; Benzaldehyde; Oxidation; Asymmetric Hydrocyanation; Mechanism The cyclic dipeptide cyclo- is found to catalyse the oxidation of benzaldehyde to benzoic acid.A mechanism is proposed both for this reactio
Salen-ligands based on a planar-chiral hydroxyferrocene moiety: Synthesis, coordination chemistry and use in asymmetric silylcyanation
Niemeyer, Jochen,Cloppenburg, Jeannine,Fr?hlich, Roland,Kehr, Gerald,Erker, Gerhard
, p. 1801 - 1812 (2010)
Condensation of the O-protected hydroxyferrocene carbaldehyde (Sp)-1 with suitable diamines, followed by liberation of the hydroxyferrocene moiety leads to a new type of ferrocene-based salen ligands (3). While the use of ethylenediamine in the
Asymmetric Cyanohydrin Synthesis catalysed by a Synthetic Cyclic Dipeptide
Oku, Jun-ichi,Inoue, Shohei
, p. 229 - 230 (1981)
Asymmetric addition of hydrogen cyanide to benzaldehyde catalysed by cyclo(L-phenylalanyl-L-histidine) gave the highest optical yield ever obtained.
Asymmetric synthesis XXVII: Asymmetric catalytic trimethylsilylcyanation of aldehydes by novel Ti-chiral Schiff base complexes
Jiang,Zhou,Hu,Li,Mi
, p. 2915 - 2916 (1995)
Enantioselective catalytic trimethylsilylcyanations of aldehydes with 48% to 92% e.e. have been studied using the novel Ti-chiral Schiff base complexes. We have found that the catalyst led to high enantioselectivity when the molar ratio of the Schiff base
Trimethylsilylcyanation of aromatic aldehydes catalyzed by Pybox-AlCl3 complex
Iovel, Irina,Popelis, Yuris,Fleisher, Mendel,Lukevics, Edmunds
, p. 1279 - 1285 (1997)
A series of aromatic and heterocyclic cyanohydrins and their O-silyl ethers have been synthesized by trimethylsilylcyanation of aldehydes using a catalyst generated in situ from (S,S)-2,6-bis(4'-isopropyloxazolin-2'-yl)pyridine (Pybox) with AlCl3/su
Catalytic Promiscuity of Ancestral Esterases and Hydroxynitrile Lyases
Devamani, Titu,Rauwerdink, Alissa M.,Lunzer, Mark,Jones, Bryan J.,Mooney, Joanna L.,Tan, Maxilmilien Alaric O.,Zhang, Zhi-Jun,Xu, Jian-He,Dean, Antony M.,Kazlauskas, Romas J.
, p. 1046 - 1056 (2016)
Catalytic promiscuity is a useful, but accidental, enzyme property, so finding catalytically promiscuous enzymes in nature is inefficient. Some ancestral enzymes were branch points in the evolution of new enzymes and are hypothesized to have been promiscuous. To test the hypothesis that ancestral enzymes were more promiscuous than their modern descendants, we reconstructed ancestral enzymes at four branch points in the divergence hydroxynitrile lyases (HNL's) from esterases ～100 million years ago. Both enzyme types are α/β-hydrolase-fold enzymes and have the same catalytic triad, but differ in reaction type and mechanism. Esterases catalyze hydrolysis via an acyl enzyme intermediate, while lyases catalyze an elimination without an intermediate. Screening ancestral enzymes and their modern descendants with six esterase substrates and six lyase substrates found higher catalytic promiscuity among the ancestral enzymes (P 0.01). Ancestral esterases were more likely to catalyze a lyase reaction than modern esterases, and the ancestral HNL was more likely to catalyze ester hydrolysis than modern HNL's. One ancestral enzyme (HNL1) along the path from esterase to hydroxynitrile lyases was especially promiscuous and catalyzed both hydrolysis and lyase reactions with many substrates. A broader screen tested mechanistically related reactions that were not selected for by evolution: decarboxylation, Michael addition, γ-lactam hydrolysis and 1,5-diketone hydrolysis. The ancestral enzymes were more promiscuous than their modern descendants (P = 0.04). Thus, these reconstructed ancestral enzymes are catalytically promiscuous, but HNL1 is especially so.
Chiral sulfoxide ligands in catalytic asymmetric cyanohydrin synthesis
Rowlands, Gareth J.
, p. 236 - 240 (2003)
A novel chiral sulfoxide-containing ligand for the catalytic addition of trimethylsilylcyanide to aldehydes is reported. The sulfoxide moiety was found to be vital for reactivity.
Asymmetric synthesis of an (R)-cyanohydrin using enzymes entrapped in lens-shaped gels.
Groeger,Capan,Barthuber,Vorlop
, p. 1969 - 1972 (2001)
[structure: see text] A novel synthesis of (R)-cyanohydrins is described which is based on the use of cross-linked and subsequently poly(vinyl alcohol)-entrapped (R)-oxynitrilases. These immobilized lens-shaped biocatalysts have a well-defined macroscopic
One-pot chemoenzymatic synthesis of protected cyanohydrins
Purkarthofer, Thomas,Skranc, Wolfgang,Weber, Hansj?rg,Griengl, Herfried,Wubbolts, Marcel,Scholz, Gerald,P?chlauer, Peter
, p. 735 - 739 (2004)
In a chemoenzymatic one-pot reaction of ethyl cyanoformate with benzaldehyde catalyzed by the hydroxynitrile lyase from Prunus amygdalus ethoxycarbonylated (R)-mandelonitrile is formed in a highly enatioselective manner. The reaction was performed both in
Hydroxynitrile Lyase of Wild Apricot (Prunus armeniaca L.): Purification, Characterization and Application in Synthesis of Enantiopure Mandelonitrile
Asif, Mohammad,Bhalla, Tek Chand
, p. 1118 - 1127 (2016)
Abstract: Hydroxynitrile lyases (HNLs) are increasingly finding application in synthesis of enantiomerically pure cyanohydrins. Cyanohydrins are important intermediates in the production of pharmaceuticals and agrochemicals. In the present studies seeds of wild apricot (Prunus armeniaca L.) have emerged as potential source of hydroxynitrile lyase. The HNL of wild apricot (ParsHNL) was purified 8.1 fold and 18.2?% yield with a specific activity of 141 units?mg?1 protein. The SDS-PAGE of the enzyme revealed that it consists of subunits of 40 and 37?kDa. However, the molecular weight of holoenzyme was assessed to be 360?kDa. The enzyme showed maximum activity in 0.1?M sodium-citrate buffer having pH 4.75 at 25?°C. Thermostability studies revealed that this HNL showed activity up to 70?°C temperature and quite stable up to 50?°C. Activation energy of ParsHNL was calculated to be 37.83?kJ?mol?1. This enzyme has Km of 3.76?mM, Vmax of 188.4?μmol?mg?1 min?1 and kcat of 1130.4?s?1 using mandelonitrile as substrate while for reverse reaction using benzaldehyde as substrate it showed Km of 16.1?mM, Vmax of 7.21?μmol?mg?1 min?1 and kcat of 43.3?s?1. Synthesis of mandelonitrile was carried out using ParsHNL and finally 8.88?mmole (1.184?g) of mandelonitrile was recovered which corresponded to 89?% molar conversion with 96?% ee for R-mandelonitrile. The yield of mandelonitrile was 411?μmol?mg?1h?1. These results indicated that ParsHNL has very high potential for synthesis of cyanohydrins and can be used for the production of enantiopure cyanohydrins. Graphical Abstract: [Figure not available: see fulltext.]
