Bifuctional Amino-Squaramides Catalyzed Asymmetric Spiroannulation Cascades with Aliphatic β,γ-Unsaturated α-Keto Esters: Controlling an Aldehyde Enolate
摘要:
A quinidine-derived squaramide Ib catalyzed cyclization reaction of beta-oxo aldehydes 1 and aliphatic or aromatic beta,gamma-unsaturated alpha-keto ester 2 is described. Using cyclic aldehyde substrates, this procedure provided a promising approach to a variety of spiro-3,4-dihydropyrans bearing three continuous quaternary and tertiary stereocenters in moderate to good yield with high stereoselectivities. Substituents on the nitrogen atoms of the squaramide moiety of the catalyst proved crucial to the reaction outcome. The stereochemistry of the three newly formed chiral centers (trans-selective) of the major product indicates a Micheal addition/hemiacetalization domino sequence for the present annulations.
Deltamides and Croconamides: Expanding the Range of Dual H‐bond Donors for Selective Anion Recognition
作者:Vincent E. Zwicker、Karen K. Y. Yuen、David G. Smith、Junming Ho、Lei Qin、Peter Turner、Katrina A. Jolliffe
DOI:10.1002/chem.201704388
日期:2018.1.24
differences in anionbinding selectivity were observed upon comparison of the dual H‐bond cores. Whereas the squaramides display similar affinity for both chloride and acetate ions, the ureas have significantly higher affinity for acetate than chloride ions and the deltamides display higher affinity for dihydrogenphosphate ions than other oxoanions or halides. These inherent differences in binding affinity
双氢键供体被广泛用作阴离子受体的识别基序。我们报告了一个双H键受体文库的合成,该文库结合了分别称为deltamides和croconamides的delticamide和croconic acid衍生物,并比较了它们的阴离子结合亲和力(对于单价物质)和Brønsted酸与井中的酸建立的尿素和方酰胺双重H键供体基序。对于具有相同取代基的双氢键核,布朗斯台德酸度的趋势是大分子烯酮酰胺>方酸酰胺>δ-酰胺>尿素,与相应的尿素相比,大分子烯醇酰胺的酸性高10-15 p K a单位。与尿素,deltamides和squaramides显示的趋势相反,N,N'-二烷基交联酰胺显示出比N,N'-二芳基衍生物更高的对氯的结合亲和力,这归因于N,N'-二芳基衍生物在中性pH下的部分去质子化。比较双H键核后,在阴离子结合选择性上存在许多差异。方酸酰胺对氯离子和乙酸根离子显示相似的亲和力,而脲对氯乙酸根的亲和力
1-Heterocyclylamino-2-hydroxy-3-amino-ω-arylalkanes of formula (I) and the salts thereof have renin-inhibiting properties and can be used as antihypertensive, medicinally active ingredients.
First Use of Thiosquaramides as Polymerization Catalysts: Controlled ROP of Lactide Implicating Key Secondary Interactions for Optimal Performance
作者:Gaël Printz、Dmytro Ryzhakov、Christophe Gourlaouen、Béatrice Jacques、Samir Messaoudi、Françoise Dumas、Franck Le Bideau、Samuel Dagorne
DOI:10.1002/cctc.202301207
日期:2024.1.8
The use of thiosquaramides as polymerizationcatalysts is shown to be effective for the controlled ROP of lactide in the presence of an alcohol source and NEt3. Comparison of their catalytic performances with less acidic squaramides is also discussed. DFT-supported calculations on thiosquaramide-mediated lactide ROP catalysis suggest that secondary interactions between the thiosquaramide N-substituents
[EN] 1-Heterocyclylamino-2-hydroxy-3-amino-?-arylalkanes of formula (I) and the salts thereof have renin-inhibiting properties and can be used as antihypertensive, medicinally active ingredients. [FR] L'invention concerne des 1-hétérocyclylamino-2-hydroxy-3-amino-?-arylalcanes de formule (I) et leurs sels, qui présentent des propriétés d'inhibition de la rénine et peuvent être utilisés comme ingrédients antihypertenseurs à activité médicinale.