4198-87-2Relevant academic research and scientific papers
Effect of basic and acidic additives on the separation of some basic drug enantiomers on polysaccharide-based chiral columns with acetonitrile as mobile phase
Gogaladze, Khatuna,Chankvetadze, Lali,Tsintsadze, Maia,Farkas, Tivadar,Chankvetadze, Bezhan
, p. 228 - 234 (2015/03/18)
The separation of enantiomers of 16 basic drugs was studied using polysaccharide-based chiral selectors and acetonitrile as mobile phase with emphasis on the role of basic and acidic additives on the separation and elution order of enantiomers. Out of the studied chiral selectors, amylose phenylcarbamate-based ones more often showed a chiral recognition ability compared to cellulose phenylcarbamate derivatives. An interesting effect was observed with formic acid as additive on enantiomer resolution and enantiomer elution order for some basic drugs. Thus, for instance, the enantioseparation of several β-blockers (atenolol, sotalol, toliprolol) improved not only by the addition of a more conventional basic additive to the mobile phase, but also by the addition of an acidic additive. Moreover, an opposite elution order of enantiomers was observed depending on the nature of the additive (basic or acidic) in the mobile phase.
Asymmetric hydrolytic kinetic resolution with recyclable polymeric Co(iii)-salen complexes: A practical strategy in the preparation of (S)-metoprolol, (S)-toliprolol and (S)-alprenolol: Computational rationale for enantioselectivity
Roy, Tamal,Barik, Sunirmal,Kumar, Manish,Kureshy, Rukhsana I.,Ganguly, Bishwajit,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
, p. 3899 - 3908 (2015/02/19)
A series of chiral polymeric Co(iii)-salen complexes based on a number of achiral and chiral linkers were synthesized and their catalytic performances were assessed in the asymmetric hydrolytic kinetic resolution of terminal epoxides. The effects of the linker were judiciously studied and it was found that in the case of the chiral BINOL-based polymeric salen complex 1, there was an enrichment in catalyst reactivity and enantioselectivity of the unreacted epoxide, particularly in the case of short as well as long chain aliphatic epoxides. Good isolated yields of the unreacted epoxide (up to 46% compared to 50% theoretical yield) along with high enantioselectivity (up to 99%) were obtained in most cases using catalyst 1. Further studies showed that catalyst 1 could retain its catalytic activity for six cycles under the present reaction conditions without any significant loss in activity or enantioselectivity. To show the practical applicability of the above synthesized catalyst we have synthesised some potent chiral β-blockers in moderate yield and high enantioselectivity using complex 1. The DFT (M06-L/6-31+G??//ONIOM(B3LYP/6-31G?:STO-3G)) calculations revealed that the chiral BINOL linker influences the enantioselectivity achieved with Co(iii)-salen complexes. Further, the transition state calculations show that the R-BINOL linker with the (S,S)-Co(iii)-salen complex is energetically preferred over the corresponding S-BINOL linker with the (S,S)-Co(iii)-salen complex for the HKR of 1,2-epoxyhexane. The role of non-covalent C-H?π interactions and steric effects has been discussed to control the HKR reaction of 1,2-epoxyhexane.
A new catalyst for the asymmetric Henry reaction: Synthesis of β-nitroethanols in high enantiomeric excess
White, James D.,Shaw, Subrata
, p. 6270 - 6273 (2013/02/23)
A new chiral tetrahydrosalen ligand has been designed and synthesized from cis-2,5-diaminobicyclo[2.2.2]octane. The complex generated in situ by the interaction of the ligand with (CuOTf)2·C6H 5CH3 was an efficient catalyst for the asymmetric Henry reaction, producing nitroaldol products in high yield and good stereoselectivity. Henry reactions catalyzed by this tetrahydrosalen-Cu(I) complex led to syntheses of β-adrenergic blocking agents (S)-toliprolol, (S)-moprolol, and (S)-propanolol.
Rearrangement of N-alkyl 1,2-amino alcohols. Synthesis of (S)-toliprolol and (S)-propanolol
Duthion, Béranger,Métro, Thomas-Xavier,Gomez Pardo, Domingo,Cossy, Janine
experimental part, p. 6696 - 6706 (2011/02/26)
N-alkyl 1,2-amino alcohols were rearranged stereospecifically by using TFAA/Et3N. This rearrangement has been used to synthesize N-isopropyl-3-(aryloxy)-2-hydroxypropylamines, β-adrenergic blocking agents such as (S)-toliprolol and (S)-propanolol.
Asymmetric synthesis of aryloxypropanolamines via OsO4-catalyzed asymmetric dihydroxylation
Sayyed, Iliyas A.,Thakur, Vinay V.,Nikalje, Milind D.,Dewkar, Gajanan K.,Kotkar,Sudalai
, p. 2831 - 2838 (2007/10/03)
A simple and effective procedure for the enantioselective synthesis of several β-adrenergic blocking agents incorporating the first asymmetric synthesis of celiprolol, is described. The key steps are (i) sharpless asymmetric dihydroxylation of aryl allyl ethers to introduce chirality into the molecules and (ii) conversion of cyclic sulfates into the corresponding epoxides using a three-step procedure.
Jacobsen-type enantioselective hydrolysis of aryl glycidyl ethers. 31P NMR analysis of the enantiomeric composition of oxiranes
Bredikhin,Strunskaya,Novikova,Azancheev,Sharafutdinova,Bredikhina
, p. 213 - 218 (2007/10/03)
The enantioselective partial hydrolysis of a number of racemic aryl glycidyl ethers in the presence of chiral Co(salen)-catalyst was studied. The enantiomeric composition of the isolated (R)-aryl glycidyl ethers was analyzed by 31P NMR using optically active substituted 2-chloro-1,3,2- dioxaphospholanes. A synthesis of β-adrenoblocking agents (S)-toliprolol and (S)-moprolol based on the simultaneously obtained (S)-3-aryloxypropane-1,2- diols was proposed.
Enzyme Assisted Preparation of Enantiomerically Pure β-Adrenergic Blockers III. Optically Active Chlorohydrin Derivatives and Their Conversion
Ader, Ulrich,Schneider, Manfred P.
, p. 521 - 524 (2007/10/02)
Optical active chlorohydrin derivatives 2a-m and 3a-m of both enantiomeric series were prepared via both enzymatic hydrolyses and acyltransfer reactions catalysed by a highly selective lipase from Pseudomonas sp..The resulting building blocks were further transformed into the corresponding β-blockers of high enantiomeric purity.
