41720-98-3Relevant articles and documents
A method for the racemization of 2-methylpyrrolidine: A histamine H 3 receptor pharmacophore
Yerande, Swapnil G.,Yerande, Ragini S.,Thakare, Prashant P.,Shendage, Deepak M.,Galave, Sharad,Gangopadhyay, Ashok Kumar
, p. 652 - 655 (2014)
This paper describes a method for the racemization of unwanted (S)-1 isomer arising from the resolution of (±)-1. The process of racemization involves thiyl radical-mediated reversible hydrogen abstraction at the chiral center, in the presence of AIBN in water. The racemized isomer was subsequently resolved by l-(+)-tartaric acid to get (R)-1, a histamine H3 receptor pharmacophore. We foresee that such an approach of racemization will be industrially useful for recycling waste (S)-1 enantiomer.
Enzyme Toolbox: Novel Enantiocomplementary Imine Reductases
Scheller, Philipp N.,Fademrecht, Silvia,Hofelzer, Sebastian,Pleiss, Jürgen,Leipold, Friedemann,Turner, Nicholas J.,Nestl, Bettina M.,Hauer, Bernhard
, p. 2201 - 2204 (2014)
Reducing reactions are among the most useful transformations for the generation of chiral compounds in the fine-chemical industry. Because of their exquisite selectivities, enzymatic approaches have emerged as the method of choice for the reduction of C=O
Acylative kinetic resolution of racemic methyl-substituted cyclic alkylamines with 2,5-dioxopyrrolidin-1-yl (: R)-2-phenoxypropanoate
Bartashevich, Ekaterina V.,Chulakov, Evgeny N.,Ezhikova, Marina A.,Gruzdev, Dmitry A.,Kodess, Mikhail I.,Korolyova, Marina A.,Krasnov, Victor P.,Levit, Galina L.,Tumashov, Andrey A.,Vakarov, Sergey A.
supporting information, p. 862 - 869 (2022/02/03)
The diastereoselective acylation of a number of racemic methyl-substituted cyclic alkylamines with active esters of 2-phenoxypropanoic acid was studied in detail. The ester of (R)-2-phenoxypropanoic acid and N-hydroxysuccinimide was found to be the most selective agent. The highest stereoselectivity was observed in the kinetic resolution of racemic 2-methylpiperidine in toluene at -40 °C (selectivity factor s = 73) with the predominant formation of (R,R)-amide (93.7% de). To explain the observed stereoselectivity, DFT modelling of the transition states in the reactions of the title acylating agent with 2-methylpiperidine and 2-methylpyrrolidine was performed. The calculated values were in good agreement with experimental data. It has been demonstrated that the acylation proceeds via a concerted mechanism, in which the addition of an amine occurs simultaneously with the elimination of the hydroxysuccinimide fragment. The high stereoselectivity of the (R,R)-amide formation is largely ensured by the lower steric hindrances in the transition states as compared to the formation of (R,S)-amide.
Stereoselective Biotransformations of Cyclic Imines in Recombinant Cells of Synechocystis sp. PCC 6803
Büchsenschütz, Hanna C.,Vidimce-Risteski, Viktorija,Eggbauer, Bettina,Schmidt, Sandy,Winkler, Christoph K.,Schrittwieser, Joerg H.,Kroutil, Wolfgang,Kourist, Robert
, p. 726 - 730 (2019/12/27)
Light-driven biotransformations in recombinant cyanobacteria allow to employ photosynthetic water-splitting for cofactor-regeneration and thus, to save the use of organic electron donors. The genes of three recombinant imine reductases (IREDs) were expressed in the cyanobacterium Synechocystis sp. PCC 6803 and eight cyclic imine substrates were screened in whole-cell biotransformations. While initial reactions showed low to moderate rates, optimization of the reaction conditions in combination with promoter engineering allowed to alleviate toxicity effects and achieve full conversion of prochiral imines with initial rates of up to 6.3 mM h?1. The high specific activity of up to 22 U gCDW ?1 demonstrates that recombinant cyanobacteria can provide large amounts of NADPH during whole cell reactions. The excellent optical purity of the products with up to >99 %ee underlines the usefulness of cyanobacteria for the stereoselective synthesis of amines.
One-Pot Synthesis of Chiral N-Arylamines by Combining Biocatalytic Aminations with Buchwald–Hartwig N-Arylation
Ahmed, Syed T.,Cosgrove, Sebastian C.,Parmeggiani, Fabio,Thompson, Matthew P.,Turner, Nicholas J.
supporting information, p. 18156 - 18160 (2020/08/13)
The combination of biocatalysis and chemo-catalysis increasingly offers chemists access to more diverse chemical architectures. Here, we describe the combination of a toolbox of chiral-amine-producing biocatalysts with a Buchwald–Hartwig cross-coupling reaction, affording a variety of α-chiral aniline derivatives. The use of a surfactant allowed reactions to be performed sequentially in the same flask, preventing the palladium catalyst from being inhibited by the high concentrations of ammonia, salts, or buffers present in the aqueous media in most cases. The methodology was further extended by combining with a dual-enzyme biocatalytic hydrogen-borrowing cascade in one pot to allow for the conversion of a racemic alcohol to a chiral aniline.
