371-27-7Relevant academic research and scientific papers
Lipase-catalyzed kinetic resolution of 7-, 8- and 12-membered alicyclic β-amino esters and N-hydroxymethyl-β-lactam enantiomers
Gyarmati, Zsuzsanna Cs.,Liljeblad, Arto,Rintola, Mikko,Bernath, Gabor,Kanerva, Liisa T.
, p. 3805 - 3814 (2003)
Enzymatic kinetic resolutions of methyl cis-2-aminocycloheptane-, 2-aminocyclooctane- and 2-aminocyclododecanecarboxylates with Candida antarctica lipase A in diisopropyl ether (E >200) and of the corresponding N-hydroxymethyl-β-lactams with Pseudomonas cepacia lipase in dry acetone (E from 27 to >200) has been performed with 2,2,2-trifluoroethyl butanoate as the best acyl donor, with both enantiomers being obtained. trans-13-Hydroxymethyl-13-azabicyclo[10.2.0]tetradecan-14-one was resolved with vinyl butanoate and Candida antarctica lipase B (E=26) in acetone.
Preparation and characterization of trifluoroethyl aliphatic carboxylates as co-solvents for the carbonate-based electrolyte of lithium-ion batteries
Lu, Wei,Xie, Kai,Chen, Zhong Xue,Pan, Yi,Zheng, Chun Man
, p. 110 - 119 (2014/05/06)
In this work, a series of trifluoroethyl aliphatic carboxylates with different carbon-chain lengths in acyl group are prepared and investigated as the co-solvents for the carbonate-based electrolyte of lithium-ion batteries. The trifluoroethyl aliphatic carbonates are synthesized by a modified one-step approach, using aliphatic carboxylic acid and trifluoroethanol as the raw materials (molar ratio, 1.2:1), hydrogen ion exchange resin as the catalyst and silica gel drier as the de-hydration. The structure and electrochemical properties of the final products have been characterized by FTIR, 1H NMR, GC-MS, viscosity, conductivity meter and electrochemical measurements. The structure characterizations show that the final products have high purity. Electrochemical tests present that the co-solvents are able to improve the electrochemical performances of graphite electrode at low temperature. In particular, we find that an addition of trifluoroethyl n-hexanoate (TFENH) into 1 M LiPF6/EC + EMC electrolyte can significantly decrease the Li de-intercalation potential of graphite by 540 mV and achieve a high capacity retention of 92% at 218 K. The electrochemical impedance spectroscopy (EIS) measurements indicate that the observed performance improvement at low temperature is associated with the decreased surface film resistance (R SEI) by the addition of co-solvents.
Lipase-catalyzed kinetic resolution of 2-aminocyclopentane- and 2-aminocyclohexanecarboxamides
Fitz, Monika,Lundell, Katri,Fueloep, Ferenc,Kanerva, Liisa T.
, p. 1129 - 1134 (2007/10/03)
Candida antarctica lipase B (CAL-B)-catalyzed N-acylation with 2,2,2-trifluoroethyl butanoate in solvent mixtures of tert-butyl methyl ether and tert-amyl alcohol was used to prepare all the enantiomers of cis- and trans-2-aminocyclopentane- and -cyclohexanecarboxamides. An unexpected change in enantiopreference, accompanied by low enantioselectivity, was observed when Pseudomonas cepacia lipase (cis-cyclohexane substrate) or C. antarctica lipase A (cis-cyclopentane and -cyclohexane substrates) replaced CAL-B.
Lipases in β-dipeptide synthesis in organic solvents
Li, Xiang-Guo,Kanerva, Liisa T.
, p. 5593 - 5596 (2007/10/03)
A number of β-dipeptides were prepared by two-step lipase-catalyzed reactions where N-acetylated β-amino esters were first activated as 2,2,2-trifluoroethyl esters with Candida antarctica lipase B (CAL-B). The activated esters were then used to acylate a
Enantioselective synthesis of a hindered furyl substituted allyl alcohol intermediate: A case study in asymmetric synthesis
Pihko, Ainoliisa J.,Lundell, Katri,Kanerva, Liisa,Koskinen, Ari M.P.
, p. 1637 - 1643 (2007/10/03)
In the course of the synthesis of the DEFG ring system of cneorin C 1, we were faced with the task of preparing the furyl substituted allyl alcohol 5 enantioselectively. Several different methods starting from enantioselective zinc-mediated alkylations were attempted, but none of them proved entirely satisfactory. The solution turned out to be enzymatic kinetic resolution through a highly enantioselective (E>300) acylation in the presence of Candida antarctica lipase A.
The synthesis of (11R,12S)-lactobacillic acid and its enantiomer
Coxon, Geoffrey D.,Al-Dulayymi, Juma R.,Baird, Mark S.,Knobl, Stefan,Roberts, Evan,Minnikin, David E.
, p. 1211 - 1222 (2007/10/03)
(11R,12S)-Lactobacillic acid has been prepared from 2,3-O-isopropylidene-D-glyceraldehyde, in a sequence involving asymmetric cyclopropanation, and from cis-cyclopropane-1,2-dimethanol, using enzymatic desymmetrisation. The key step in the former route wa
Candida antarctica lipase A - A powerful catalyst for the resolution of heteroaromatic β-amino esters
Solymar, Magdolna,Fueloep, Ferenc,Kanerva, Liisa T.
, p. 2383 - 2388 (2007/10/03)
Enantioselective acylations of 3-amino-3-heteroarylpropanoates (ArCH(NH2)CH2CO2Et; Ar=2- or 3-thienyl or -furyl) were performed in the presence of Candida antarctica lipase A. As a result of the excellent chemo- and enantioselectivities (E >100), gram-scale resolutions were carried out in ethyl butanoate. The hydrochloride salts of the unreacted R substrates and the butanamides of the reactive S enantiomers were thus prepared.
Transition state stabilization by micelles: Thiolysis of p-nitrophenyl alkanoates in cetyltrimethylammonium bromide micelles
Tee,Yazbeck
, p. 1100 - 1108 (2007/10/03)
Thiolysis of p-nitrophenyl esters (acetate to decanoate) by the anion of 2-mercaptoethanol (ME) is catalyzed by micelles of cetyltrimethylammonium bromide (CTAB) in aqueous solution. At fixed [ME], the observed rate constants (k(obs)) show saturation with
Synthesis of the stereoisomers of a novel antibacterial agent and interpretation of their relative activities in terms of a theoretical model of the penicillin receptor
Wolfe,Zhang,Johnston,Kim
, p. 1066 - 1075 (2007/10/02)
2,2-Dimethyl-3-(2'-hydroxypropyl)-5-carboxy-Δ3-1,4-thiazine (1) is a designed antibacterial agent. Based on an analysis of how penicillin complexes to and reacts with a model of a penicillin-binding protein, 1 contains a functional group (C=N) that can react with a serine hydroxyl group of the receptor according to the putative reaction Enz-OH + C=N → Enz-O-C-NH. Compound 1 also contains additional substituents that are designed to position the O-H and C=N groups relative to one another in the enzyme-substrate complex in a geometry that attempts to reproduce the optimum geometry of approach of two such reactants. A most important assumption is that this optimum geometry can be computed ab initio. In a first preparation of 1, (±)-5-methyl-4-hexene-2-ol (2) was converted to the lithium salt of (±)-2-mercapto-2-methyl-5-tert-butyldimethylsiloxy-3-hexanone (7), which was condensed with the N-tert-butoxycarbonyl-D- and L-serine-β-lactones (3). The synthesis was completed by deprotection with formic acid and cyclization in water. The R and S enantiomers of 2 have now been obtained, and the absolute configuration of the alcohol established, by reaction of the R- and S-propylene oxides with an organometallic reagent prepared from β,β-dimethylvinyl bromide. The R alcohol has also been secured by lipase-catalyzed transesterification with trifluoroethyl butyrate, and chemical hydrolysis of the trifluoroethyl ester. The R and S enantiomers of 2 were converted to the R and S enantiomers of 7, and these were condensed with the R and S enantiomers of 3 to yield each of the stereoisomers of the chemically unstable 1 in ca. 95% optically pure form. Antibacterial activity resides in the 5S,8R and 5S,8R isomers. These findings are shown to be consistent with the theoretical model. It is hoped that the stability of the lead structure 1 can be improved, to allow binding experiments with penicillin recognizing enzymes to proceed. 2,2-Dimethyl-3-(2′-hydroxypropyl)-5-carboxy- Δ3-1,4-thiazine (1) is a designed antibacterial agent. Based on an analysis of how penicillin complexes to and reacts with a model of a penicillin-binding protein, 1 contains a functional group (C = N) that can react with a serine hydroxyl group of the receptor according to the putative reaction Enz-OH + C = N → Enz-O-C-NH. Compound 1 also contains additional substituents that are designed to position the O-H and C = N groups relative to one another in the enzyme-substrate complex in a geometry that attempts to reproduce the optimum geometry of approach of two such reactants. A most important assumption is that this optimum geometry can be computed ab initio. In a first preparation of 1, (±)-5-methyl-4-hexene-2-ol (2) was converted to the lithium salt of (±)-2-mercapto-2-methyl-5-tert-butyldimethylsiloxy-3-hex anone (7), which was condensed with the N-tert-butoxycarbonyl-D- and L-serine-β-lactones (3). The synthesis was completed by deprotection with formic acid and cyclization in water. The R and S enantiomers of 2 have now been obtained, and the absolute configuration of the alcohol established, by reaction of the R- and S-propylene oxides with an organometallic reagent prepared from β,β-dimethylvinyl bromide. The R alcohol has also been secured by lipase-catalyzed transesterification with trifluoroethyl butyrate, and chemical hydrolysis of the trifluoroethyl ester. The R and S enantiomers of 2 were converted to the R and S enantiomers of 7, and these were condensed with the R and S enantiomers of 3 to yield each of the stereoisomers of the chemically unstable 1 in ca. 95% optically pure form. Antibacterial activity resides in the 5S,8R and 5S,8S isomers. These findings are shown to be consistent with the theoretical model. It is hoped that the stability of the lead structure 1 can be improved, to allow binding experiments with penicillin recognizing enzymes to proceed.
Enzyme Reactions in Apolar Solvent. 5. The Effect of Adjacent Unsaturation on the PPL-Catalyzed Kinetic Resolution of Secondary Alcohols
Morgan, Brian,Oehlschlager, Allan C.,Stokes, Thomas M.
, p. 3231 - 3236 (2007/10/02)
The effect of adjacent unsaturation on the enzyme-catalyzed kinetic resolution of secondary alcohols is studied for a series of allylic, homoallylic, propargylic, homopropargylic, and phenyl-substituted 2-alkanols, using porcine pancreatic lipase (PPL) in anhydrous Et2O.Excellent enantioselectivity (high E value) was observed for α-phenethyl alcohol (3), propargylic alcohols (8 and 11), and (E)-allylic alcohols (9 and 12), but (Z)-allylic alcohols (10 and 13) showed poor selectivity.Enantioselectivity was also low for both (E)- and (Z)-homoallylic alcohols (15 and 16), homopropargylic alcohol (14), 1-phenyl-2-propanol (6), and 4-phenyl- 2-butanol (7).The enhanced enantioselectivity observed for (E)-allylic alcohols was exploited in the synthesis of the enantiomers of both components of the aggregation pheromone of the lesser grain borer, Rhyzopertha dominica (F.).The magnitude of the enantiomeric ratio (E value) can be dramatically affected by the accuracy of the values of ees and eep used in the calculation, especially when E is large.Variation in the value of E with the optical purity of the chiral derivatizing agent used to determine ees and eep is illustrated.
