148345-21-5Relevant articles and documents
Enzyme Promiscuity as a Remedy for the Common Problems with Knoevenagel Condensation
Koszelewski, Dominik,Ostaszewski, Ryszard
, p. 10156 - 10164 (2019/07/09)
A new protocol based on lipase-catalyzed tandem reaction toward α,β-enones/enoesters is presented. For the synthesis of the desired products the tandem process based on enzyme-catalyzed hydrolysis and Knoevenagel reaction starting from enol acetates and aldehyde is developed. The relevant impact of the reaction conditions including organic solvent, enzyme type, and temperature on the course of the reaction was revealed. It was shown that controllable release of the active methylene compound from the corresponding enol carboxylate ensured by enzymatic reaction diminishes significantly the formation of the unwanted co-products. Furthermore, this protocol was extended by including a second tandem chemoenzymatic transformation engaging various aldehyde precursors. After a careful optimization of the reaction conditions, the target products were obtained with yields up to 86 % and with excellent E/Z-selectivity.
Cationic vanadium(IV) complexes as efficient catalysts for nazarov cyclizations
Walz, Irene,Bertogg, Andreas,Togni, Antonio
, p. 2650 - 2658 (2008/02/08)
Vanadium(IV) species generated in situ from V(salen)Cl2 complexes (1) by reaction with 2 equiv. of AgSbF6 are effective catalysts for Nazarov cyclizations. Thus, dialkenyl ketones bearing α-ester groups are efficiently converted to c
Synthesis of Ethyl 2-Aminodihydro-5-pyrimidinecarboxylate Derivatives and 3,7-Diethoxycarbonyl-4,6-dihydro-2,4,6,8-tetraaryl-lH-pyrimido[1,2-a]pyrimidines
Milcent, Rene,Malanda, Jean-Claude,Barbier, Geo,Vaissermann, Jacqueline
, p. 329 - 336 (2007/10/03)
Reactions of ethyl 3-aryl-2-benZoylpropenoateS 1 with guanidine and N-alkyl(or benzyl)guanidines have been investigated. Ethyl 2-aminodihydro-5-pyrimidinecarboxylate derivatives 3, 4 or 5 and 3,7-diethoxycarbonyl-4,6-dihydro-2,4,6,8-tetraaryl-lH-pyrimido[
RING-OPENING OF 4-ISOXAZOLINES: COMPETITIVE FORMATION OF ENAMINO DERIVATIVES AND α,β-ENONES
Chiacchio, Ugo,Casuscelli, Franco,Liguori, Angelo,Rescifina, Antonio,Romeo, Giovanni,et al.
, p. 585 - 600 (2007/10/02)
Ring-opening of 3-substituted 4-isoxazolines, proceeding through the intermediate isoxazolinium salts, follows two competing reaction pathways leading to α,β-enones and enamines respectively.The rearrangement courses can be controlled as a function of substitution pattern and experimental conditions.