875438-79-2Relevant academic research and scientific papers
Stereoselective synthesis of 2,4,5-trisubstituted piperidines via radical cyclization
Ragoussi, Maria-Eleni,Walker, Stephen M.,Piccanello, Andrea,Kariuki, Benson M.,Horton, Peter N.,Spencer, Neil,Snaith, John S.
, p. 7347 - 7357 (2011/02/16)
A novel approach to 2,4,5-trisubstituted piperidines is reported, involving the 6-exo cyclization of stabilized radicals onto α,β-unsaturated esters. Only two of the four possible diastereoisomers are observed, with diastereomeric ratios ranging from 3:2
Synthesis of novel N-protected β3-amino nitriles: study of their hydrolysis involving a nitrilase-catalyzed step
Veitia, Maite Sylla-Iyarreta,Brun, Pierre Louis,Jorda, Pierre,Falguieres, Annie,Ferroud, Clotilde
experimental part, p. 2077 - 2089 (2010/03/04)
Several commercially available nitrilases were investigated with regard to their potential to hydrolyze N-protected β3-amino nitriles into their corresponding N-protected β3-amino acids. The biotransformations were obtained in different proportions depending on the nitrilase involved. The best hydrolysis results were achieved for the N-Cbz-β3-amino nitrile from l-alanine using the NIT-107, in a phosphate buffer at 0.05 M. However, no biotransformation into the corresponding acids was observed for the N-sulfonylamide β3-amino nitriles. Two simple and efficient procedures to prepare the β3-amino nitriles from their analogous α-amino acids are described. Thirty four new substances were synthesized and characterized over the course of this work.
Synthesis and biological evaluation of reversible inhibitors of IdeS, a bacterial cysteine protease and virulence determinant
Berggren, Kristina,Johansson, Bjoern,Fex, Tomas,Kihlberg, Jan,Bjoerck, Lars,Luthman, Kristina
experimental part, p. 3463 - 3470 (2009/09/25)
Analogues of the irreversible protease inhibitors TPCK and TLCK have been synthesized and tested as inhibitors of the bacterial cysteine protease IdeS excreted by Streptococcus pyogenes. Eight compounds were identified as inhibitors of IdeS in an in vitro
Stereoselective synthesis of 2,4,5-trisubstituted piperidines by carbonyl ene and Prins cyclisations
Cariou, Claire A.M.,Kariuki, Benson M.,Snaith, John S.
supporting information; experimental part, p. 3337 - 3348 (2009/02/05)
An approach to 2,4,5-trisubstituted piperidines is reported, in which the key step is the Prins or carbonyl ene cyclisation of aldehydes of the type 1. Prins cyclisation catalysed by concentrated hydrochloric acid in CH 2Cl2 at -78 °C afforded good yields of two of the four possible diastereomeric piperidines, with the 4,5-cis product 7 predominating in a diastereomeric ratio of up to 94: 6. The diastereoselectivity of the cyclisation decreased as the 2-substituent increased in size, becoming unselective for very bulky 2-substituents. In contrast, cyclisation catalysed by MeAlCl2 in CH2Cl2 or CHCl3 at temperatures of between 20-60 °C, favoured the 4,5-trans diastereomer 8, in a diastereomeric ratio of up to 99: 1. The low-temperature cyclisations catalysed by HCl proceed under kinetic control via a mechanism involving the development of significant carbocationic character, in which the 4,5-cis cation is more stable than the 4,5-trans cation as a result of overlap with the neighbouring oxygen. The cyclisations catalysed by MeAlCl2 proceed under thermodynamic control, affording the product in which both the 4- and 5-substituents are equatorial.
A convenient synthetic route to enantiopure N-tosylazetidines from α-amino acids
Ghorai, Manas K.,Das, Kalpataru,Kumar, Amit
, p. 2471 - 2475 (2007/10/03)
A general and convenient synthetic route to various chiral 2-substituted- and 2,4-disubstituted-N-tosylazetidines (ee >99%) is described in good overall yields starting from chiral α-amino acids using very simple chemistry.
Stereoselective synthesis of 2,4,5-trisubstituted piperidines by carbonyl ene and Prins cyclisations
Cariou, Claire A. M.,Snaith, John S.
, p. 51 - 53 (2007/10/03)
Intramolecular carbonyl ene reactions present a method for ring closure, leading to the formation of two contiguous stereocentres with an often high degree of stereocontrol. The extension of this approach to the synthesis of 2,4,5-trisubstituted piperidin
