Cucurbit[8]uril-mediated photodimerization of alkyl 2-naphthoate in aqueous solution
摘要:
The photodimerization of methyl 2-naphthoate (1), ethyl 2-naphthoate (2) and butyl 2-naphthoate (3) in cucurbituril (CB) aqueous solution was investigated. The product distribution and fluorescence spectral changes suggest that CB[S] can encapsulate two molecules of alkyl 2-naphthoate (1 or 2) and thereby facilitate a cubane-like photodimer formation. Subtle changes in either cavity size of CB[n] or alkyl substitutes can significantly modulate the interaction of CB[n] with 2-naphthoate derivatives affording remarkable alterations in their photochemical reactivity. (c) 2007 Elsevier Ltd. All rights reserved.
An effective method for alkoxycarbonylation of (hetero)aryl bromides is developed in the presence of in situ-generated phosphinite ligands tBu2POR (R = nBu, nPr, Et or Me). For this purpose commercially available tBu2PCl was used as the pre-ligand in the presence of different alcohols. For the first time cross coupling reactions with two alcohols – one generating the ligand, the other used as substrate
在原位生成的次膦酸酯配体t Bu 2 POR(R = n Bu,n Pr,Et或Me)存在下,开发了一种用于(杂)芳基溴的烷氧羰基化的有效方法。为此目的,在不同醇存在下,将可商购的t Bu 2 PC1用作预配体。首次开发了与两种醇的交叉偶联反应-一种生成配体,另一种用作底物。通过这种方法,可以以更有效的方式进行配体优化,并且可以以良好的产率和选择性获得所需的产物。
esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr‐MOF‐808‐P can promote the reaction for a wide range of primary, secondary and tertiary amides with n‐butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five
Selective conversion of primary amides to esters promoted by KHSO4
作者:Narsimha Sattenapally、Jhanvi Sharma、Yuqing Hou
DOI:10.24820/ark.5550190.p010.392
日期:——
Primary amides, either aliphatic or aromatic, are easily converted to the corresponding esters via reflux in lower primary alcohols in the presence of KHSO4. Secondary amides lead to complicated mixtures under analogous conditions, whereas tertiary amides were inert. Use of isopropyl alcohol resulted in the formation of product at slower rate and lower yield along with side products, whereas, use of
Palladium-Catalyzed Reductive Carbonylation of Aryl Halides with<i>N</i>-Formylsaccharin as a CO Source
作者:Tsuyoshi Ueda、Hideyuki Konishi、Kei Manabe
DOI:10.1002/anie.201303926
日期:2013.8.12
Easy peasy: The title reaction employs N‐formylsaccharin, which is an easily accessible crystalline compound, as an effective COsource. The reactions proceed with a small excess of the COsource at moderate temperatures and were successfully applied to a wide range of aryl bromides. DMF=N,N‐dimethylformamide, dppb=1,4‐bis‐(diphenylphosphino)butane.
Ethyl 2-Cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (<i>o</i>-NosylOXY): A Recyclable Coupling Reagent for Racemization-Free Synthesis of Peptide, Amide, Hydroxamate, and Ester
byproducts that can be easily recovered and reused for the synthesis of the same reagent, making the method more environmentally friendly and cost-effective. The synthesis of amides, hydroxamates, peptides, and esters using this reagent is described. The synthesis of the difficult sequences, for example, the islet amyloid polypeptide (22–27) fragment (with a C-terminal Gly, H-Asn-Phe-Gly-Ala-Ile-Leu-Gly-NH2)