Microwave-assisted Cadogan reaction for the synthesis of 2-aryl-2<i>H</i>-indazoles, 2-aryl-1<i>H</i>-benzimidazoles, 2-carbonylindoles, carbazole, and phenazine
mixed with triethylphosphite or triphenylphosphine and irradiated with microwaves for several minutes at a specific power to give the desired products. The indazoles were prepared by irradiating N‐(2‐nitrobenzylidene) anilines with triethylphosphite at 200 W for 12–14 min to give 85–92% product yields. Irradiation of the mixture of N‐benzylidene‐2‐nitroanilines and triphenylphosphine at 200 W for
Catalytic Asymmetric Synthesis of Dihydroquinazolinones from Imines and 2-Aminobenzamides
作者:Dao-Juan Cheng、Yu Tian、Shi-Kai Tian
DOI:10.1002/adsc.201100849
日期:2012.4.16
An unprecedented catalytic asymmetric synthesis of aminal‐containing heterocyclic compounds has been developed from imines and tethered nitrogen/nitrogen nucleophiles. In the presence of 10 mol% of a commercially available chiral phosphoric acid, a range of aromatic, α,β‐unsaturated, and aliphatic imines react with 2‐aminobenzamides to give dihydroquinazolinones in good to excellent yields and ee.
Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst
作者:Frederik Freitag、Torsten Irrgang、Rhett Kempe
DOI:10.1021/jacs.9b05024
日期:2019.7.24
highly active and chemoselective manganese catalyst for the hydrogenation of imines. The catalyst has a large scope, can reduce aldimines and ketimines, and tolerates a variety of functional groups, among them hydrogenation sensitive examples such as an olefin, a ketone, nitriles, nitro groups and an aryl iodo substituent or a benzyl ether. We could investi-gate the transfer step between imines and the
我们介绍了一种用于亚胺加氢的高活性和化学选择性锰催化剂。该催化剂适用范围广,可还原醛亚胺和酮亚胺,可耐受多种官能团,其中对氢化敏感的例子如烯烃、酮、腈、硝基和芳基碘取代基或苄基醚。我们可以详细研究亚胺和氢化物配合物之间的转移步骤。我们发现配体的双重去质子化是必不可少的,过量的碱不会导致转移步骤中的更高速率。我们将实际的加氢催化剂鉴定为 K-Mn-双金属物种,并且可以通过 X 射线分析获得氢化物转移后形成的 K-Mn 配合物的结构。核磁共振实验表明氢化物转移是一个明确定义的反应,这是亚胺的一级,双金属(K-Mn)氢化物的一级,并且速率与钾碱的浓度无关。我们提出了一种外球机制,其中质子似乎不参与速率确定步骤,导致底物中的瞬态带负电荷的氮原子与 HOtBu(2-methylpropan-2-ol)迅速反应以产生胺。这是基于几个观察结果,例如反应速率不依赖于 HOtBu 浓度,没有可观察到的锰酰胺
Grinding Synthesis of Schiff Bases Combined with Infrared Irradiation
作者:Jian-Ying Tong、Na-Bo Sun、Hong-Ke Wu
DOI:10.14233/ajchem.2013.14382
日期:——
Solid-phase synthesis combined with infrared irradiation promoted the formation of a series of Schiff bases in the condensation reaction between substituted benzaldehydes and anilines, in the solvent free. Benzaldehydes and anilines, containing either electron withdrawing or electron-releasing groups, were evaluated their substituent effect on the formation of the Schiff bases. Moreover, this new procedure is environmentally benign because no solvent was employed in the transformations.
o-Nitroaniline derivatives. Part I. The preparation and stability of o-nitroanils
作者:R. Marshall、D. J. Sears、D. M. Smith
DOI:10.1039/j39700002144
日期:——
The formation of Schiff bases by treatment of benzaldehyde with o-nitroaniline and its derivatives proceeds best in the presence of an excess of aldehyde, under conditions which permit removal of water as soon as it is formed. The products obtained from the corresponding reactions with substituted benzaldehydes depend on the nature of the substituents.