An iridium/f-amphol catalytic system for the enantioselective hydrogenation of α-substituted β-ketoesters via dynamic kinetic resolution is reported. The desired anti products were obtained in high yields (up to 98%) with good diastereoselectivity (up to 96:4 diastereometic ratio (dr)) and excellent enantioselectivity (up to >99% enantiomeric excess (ee)). A catalytic model is proposed to explain the
Über neuartige, basisch substituierte Pyrazolon-Derivate. Untersuchungen über synthetische Arzneimittel. 3. Mitteilung
作者:A. Ebnöther、E. Jucker、A. Lindenmann
DOI:10.1002/hlca.19590420415
日期:——
Es werden neue Pyrazol-5-on-Derivate beschrieben, die in 1-Stellung durch einen Piperidyl-(4)- oder Dialkylaminoalkyl-Rest substituiert sind. Einzelne dieser Verbindungen zeichnen sich bei hervorragender Wasserlöslichkeit ihrer Hydrochloride durch gute analgetische und antipyretische Wirkungen Bus.
Catalytic asymmetric construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements
作者:Wande Zhang、Shiqiang Wei、Wenyao Wang、Jingping Qu、Baomin Wang
DOI:10.1039/d1cc01123e
日期:——
An organocatalyticasymmetric process was reported for the sterically precise construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements. A series of interesting products featuring the union of a centrally chiral pyrazolone moiety and an axially chiral styrene unit were obtained in high yield with excellent diastereoselectivity and enantioselectivity (up to 99% ee
Preparation of <i>β</i>-Keto Esters and <i>β</i>-Diketones by C-Acylation/Deacetylation of Acetoacetic Esters and Acetonyl Ketones with 1-Acylbenzotriazoles
作者:Alan R. Katritzky、Zuoquan Wang、Mingyi Wang、Chavon R. Wilkerson、C. Dennis Hall、Novruz G. Akhmedov
DOI:10.1021/jo049274l
日期:2004.10.1
Acyl-, aroyl-, and heteroaroyl-acetic esters 6a−f and 8a−l are prepared by reactions of 1-acylbenzotriazoles 1a−k with acetoacetic esters 5 or 7a,b in the presence of sodium hydride followed by regioselective deacetylation. Similar C-acylation/deacetylation of acetylacetone and benzoylacetone affords β-diketones 10a−d and 13a−c, respectively.