Although it is recognized that the presence of water is disadvantageous for imine synthesis, we demonstrate that such synthesis can be effective in completely aqueous media, without any catalyst and under mild conditions. Thus, aryl-aryl, aryl-alkyl, alkyl-aryl and alkyl-alkyl monoimines as well as a large variety of diimines are obtained by direct condensation of the corresponding carbonyl compounds and amines, in water. The same process is used to synthesize macrocyclic diimines starting from methylene, ethylene, trimethylene and tetramethylene glycol bis(2-formylphenyl ether) and ethylene-, trimethylene- and tetramethylene-diamine, some of these macrocycles being known for their chelating properties.
Indole-fused cyclic anhydrides earlier deemed unreactive in the Castagnoli-Cushman reaction with imines have been rendered valid participant in this process. The new reaction format involves the use of respective indole-based dicarboxylic acids and in situ cyclodehydration of the latter by aceticanhydride. This finding validates a fundamentally new approach to synthesizing compounds based on the privileged
早先被认为在Castagnoli-Cushman与亚胺的反应中没有反应性的吲哚稠合的环状酸酐已成为该过程的有效参与者。新的反应形式包括使用各自的基于吲哚的二羧酸和后者通过乙酸酐的原位环脱水。这一发现证实了一种根本上新颖的合成化合物的方法,该方法基于特权的1,2,3,4-四氢吡嗪并[1,2- a ]吲哚核,其特征是迄今未描述的取代方式。
Unusually Reactive Cyclic Anhydride Expands the Scope of the Castagnoli–Cushman Reaction
“azole-including” cyclic anhydrides in the Castagnoli–Cushman reaction with imines, a remarkably reactive, pyrrole-based anhydride has been identified. It displayed a remarkably efficient reaction with N-alkyl and N-aryl imines, in particular, with “enolizable” α-C-H imines which typically fail to react with a majority of known cyclic anhydrides. The reactivity of this anhydride has been justified by
of heterocyclic product space accessible by the Castagnoli–Cushman reaction (CCR) has been achieved via the use of glutaric anhydride analogues containing endocyclic substitutions with oxygen, nitrogen, and sulfur. Incorporation of these heteroatoms in the anhydride’s backbone results in enhanced reactivity and generally lower temperatures that are required for the reactions to go to completion. These
A Latent Reaction in a Model GFP Chromophore Revealed upon Confinement: Photohydroxylation of <i>ortho</i>-Halo Benzylidene-3-methylimidazolidiones via an Electrocylization Process
作者:Shampa R. Samanta、José P. Da Silva、Anthony Baldridge、Laren M. Tolbert、V. Ramamurthy
DOI:10.1021/ol5013058
日期:2014.6.20
Excited state behavior of halogensubstituted model GFP chromophores was investigated in an acetonitrile solution and in a confined environment provided by an octa acid capsule in water. Of the ortho, meta, and para halogensubstituted GFP chromophores only the ortho compounds gave a new product resulting from an unprecedented photosubstitution of halogens by the hydroxyl group. This unusual reaction