A transition-metal-free multicomponent reaction towards constructing chiral 2<i>H</i>-1,4-benzoxazine scaffolds
作者:Lixiang Zhu、Xiaoyu Ren、Juan Du、Jia-Hong Wu、Jian-Ping Tan、Jixing Che、Jianke Pan、Tianli Wang
DOI:10.1039/d0gc02134b
日期:——
transition-metal-free multicomponent cascade reaction of readily available α-halogenated ketones, ortho-aminophenols, and aldehydes using a novel dipeptide-based phosphonium salt catalyst was developed for the efficient construction of various 2H-1,4-benzoxazine derivatives with excellent functional-group tolerance. The method represents an unprecedented approach for trapping active 1,5-bifunctional intermediates
本文中,开发了一种使用新型的基于二肽的phospho盐催化剂的易于获得的α-卤代酮,邻氨基酚和醛的无过渡金属的多组分级联反应,以有效地构建各种2 H -1,4-苯并恶嗪具有出色的官能团耐受性的衍生物。该方法代表了一种空前的方法,用于捕获具有α-卤代酮的活性1,5-双功能中间体,以访问具有两个非立体诱导中心且具有两个立体生成中心的生物学上重要的苯并恶嗪支架。
Dipeptide-Based Phosphonium Salt Catalysis: Application to Enantioselective Synthesis of Fused Tri- and Tetrasubstituted Aziridines
作者:Jia-Hong Wu、Jianke Pan、Tianli Wang
DOI:10.1055/s-0039-1690192
日期:2019.12
salt catalysis. This article briefly discusses the recent development in asymmetricreactions (mainly including nucleophilic additions and cyclizations) promoted by chiral quaternary phosphonium salt catalysts. We expect that more catalyticasymmetricreactions will be developed on the basis of such new phase-transfer catalytic systems in the near future.
2-Bromo-1-tetralone derivatives of the formula
wherein R1, R2 and R3 form any one of the following combinations (A), (B) and (C):
(A) R1 = R2 = Cl and R. = H;
(B) R1 = R3 = Cl and R2 = H; and
(C) R1 = F and R2 = R3 = H.
Results of experiments indicate that these derivatives have high antitumor activity and antifungal activity with low toxicity.
Tetrazyklische beta-Lactam Antibiotika und Verfahren zur ihrer Darstellung
申请人:HOECHST AKTIENGESELLSCHAFT
公开号:EP0517065A1
公开(公告)日:1992-12-09
β-Lactam-Antibiotika der Formel I und deren pharmazeutisch verträgliche Salze,
mit
X gleich (CH₂)o-2, CR(a)R(b), O, SOo-2, NR(c)
R(1), R(2) und R(3) einer Vielzahl von Substituenten sind hervorragende Antibiotika mit bemerkenswert guter antibakterieller Wirksamkeit sowohl gegen Gram-positive als auch gegen Gran-nevative Keime. Sie weisen gegenüber der renalen Dehydropeptidase eine hohe Stabilität auf.
Sie werden durch Zyklisierung der Verbindungen II
oder III
erhalten.
式 I 的 β-内酰胺类抗生素及其药学上可接受的盐类、
其中
X 是 (CH₂)o-2、CR(a)R(b)、O、SOo-2、NR(c)
R(1)、R(2)和 R(3)的各种取代基都是极好的抗生素,对革兰氏阳性菌和革兰氏阴性菌都有显著的抗菌效果。它们对肾脱水肽酶高度稳定。
它们是由化合物 II
或 III
得到。