2038-93-9Relevant academic research and scientific papers
Uncatalysed intermolecular aza-Michael reactions
Medina, Florian,Duhal, Nathalie,Michon, Christophe,Agbossou-Niedercorn, Francine
, p. 311 - 317 (2013/08/25)
The catalyst-free reactions of activated alkenes with primary and secondary amines were investigated leading to various mono- and di-hydroamination products, the latter being rare and original. These reactions were shown to depend first on the strength of the nucleophile. Temperature and steric hindrance of the reagents were the other key factors controlling the selectivity of these aza-Michael reactions. In spite of their poor nucleophilicities, some N-heterocyclic amines could react with different activated alkenes affording valuable intermediates. Such results tended to demonstrate the hydrogen-bonding interactions between activated alkenes and poly-nitrogen aromatic cycles may control these concerted or fully conjugate aza-Michael additions.
Green, efficient and practical Michael addition of arylamines to α,β-unsaturated ketones
Jiang, Ran,Li, Dan-Hua,Jiang, Jing,Xu, Xiao-Ping,Chen, Tao,Ji, Shun-Jun
supporting information; experimental part, p. 3631 - 3637 (2011/06/21)
The aza-Michael addition of aromatic amines to α,β-unsaturated ketones was carried out effectively at room temperature in good to excellent yields without any catalyst or solvent. It was significant that part of adducts could be collected in almost quanti
Preparation of various enantiomerically pure (benzotriazol-1-yl)- and (benzotriazol-2-yl)-alkan-2-ols
Pchelka, Beata K.,Loupy, Andre,Petit, Alain
, p. 2516 - 2530 (2007/10/03)
(S)-(-)-(Benzotriazol-1-yl)- and (S)-(-)-(benzotriazol-2-yl)-alkan-2-ols 7a-9a, 7b-9b and their (R)-(+)-acetates 10a-12a and 10b-12b were prepared in high enantiomeric excess via lipase from Pseudomonas fluorescens (Amano AK) catalyzed enantioselective acetylation of racemic alcohols 4a-6a and 4b-6b with vinyl acetate in tert-butyl methyl ether or toluene at 23 °C. The enantioselectivity of this transformation was dependent on the length of the alkyl chain with E-values ranging from 30 to 57. Several benzotriazole substituted ketones 1a-3a and 1b-3b were synthesized from 1H-benzotriazole and corresponding haloketones. These compounds were stereoselectively reduced with Baker's yeast in water or in organic solvent containing 5% v/v of water at 30 °C to give the (S)-(-)-alcohol. Better stereoselectivity was observed in the kinetic resolution of racemic alcohols 4a-6a and 4b-6b (ee = 69-92% at 44-52% conversion) compared to reduction of corresponding prochiral ketones 1a-3a and 1b-3b with Baker's yeast (ee = 40-67% at 39-89% conversion). Enhanced enantioselectivities were observed at lower temperatures.
THE REACTIONS OF BENZOTRIAZOLE WITH UNSATURATED ALDEHYDES AND KETONES IN THE PRESENCE OR ABSENCE OF AMINES
Katritzky, A. R.,Rachwal, S.,Hughes, C. V.,Wang, Z.
, p. 1633 - 1652 (2007/10/02)
Benzotriazole adds to α,β-unsaturated aldehydes and ketones with the formation of the corresponding β-benzotriazolyl-aldehydes and -ketones in high yields.Unsaturated aldehydes react with a second molar equivalent of benzotriazole to form 1,3-bisbenzotriazolylalkanols or, in the presence of amines, 1,3-bisbenzotriazolylalkylamines as stable crystalline products.When treated with sodium borohydride or a Grignard reagent, these products undergo substitution of the benzotriazolyl group at C-1 by a hydrogen atom or by an alkyl (or aryl) group, respectively.The 3-benzotriazolylalkylamines obtained were characterized by 1H-NMR and 13C-NMR spectroscopy.Isomerizations between benzotriazol-1-yl and -2-yl derivatives are discussed.
