Display omitted
•Three enone dyes (C3s) bearing N-alkylated pyrrole, indole, and carbazole group were synthesized.•Photophysical and electrochemical properties of C3s were obtained.•The photon ...initiation ability of C3s with or without tertiary amine were investigated.•The different initiation performance of C3s were explained.
In this work, three enone dyes (C3s) bearing N-alkylated pyrrole (C3PY), indole (C3ID) and carbazole (C3CZ) group were synthesized and characterized to explore the effect of peripheral group on their photoinitiation ability. C3s display good light absorption in the region of 300–500 nm. Under 405/460 nm LED irradiation, the polymerization kinetics of a diacrylate monomer in the presence of one-component C3s or bimolecular C3s/triethanolamine (TEOA) were investigated by Real-time FT-IR technology. Polymerization profiles show that C3s could initiate the polymerization and TEOA significantly promote the initiation efficiency of C3CZ, while this acceleration effect is relatively small for C3PY and C3ID. To decipher these phenomenon, steady state photolysis, cyclic voltammetry and theoretical calculation were jointly performed. Accordingly, it is proposed that C3PY and C3ID tend to photolyze through intramolecular hydrogen abstraction. This work show that the peripheral group strongly affect the initiation ability of enone photoinitiator.
A novel heterogeneous alumina supported silver nanocatalyst (Ag@Al2O3) has been designed and it showed excellent catalytic activity for the N-alkylation of hetero (aromatic) amines and aromatic ...amines with alcohols as the alkylating agent.
Display omitted
We have successfully embedded rhombohedral crystallites of silver nanoparticles (Ag-NPs) over mesoporous alumina (Ag@Al2O3) material for the first time. The Ag@Al2O3 has been characterized by powder X-ray diffraction (PXRD), ultra high resolution transmission electron microscopy (UHR-TEM), scanning electron microscopy (SEM), N2 adsorption/desorption isotherm, Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible absorption spectra (UV–Vis), and thermogravimetric analysis (TGA). The PXRD confirms the presence of the rhombohedral phase of Ag nanoparticles. The agglomeration of the silver nanoparticle having a dimension of 80–90nmhas been clearly observed from UHR-TEM images. This novel nanocatalyst showed excellent catalytic activity towards the N-alkylation of hetero (aromatic) amines and aromatic amines using alcohols as the alkylating agent. The catalyst is heterogeneous in nature and can be recovered and recycled more than five reaction cycles without any noticeable loss in its catalytic activity.
3‐Amino‐substituted saturated nitrogen heterocycles are an important subclass of β‐diamines, appearing in a number of clinical agents. Herein, we report a unified approach to these products based ...upon the regioselective photoredox‐mediated hydroamination of enecarbamates. The amine coupling partner can encompass diverse amine types under a single set of reaction conditions, including primary alkyl amines, ammonia, aryl and heteroaryl amines, and N−H heterocycles. The method enables the synthesis of a wide range of pharmaceutically relevant building blocks.
Medicinally important 3‐amino‐substituted cyclic amines can be accessed in a single step by photoredox‐catalysed hydroamination of cyclic enecarbamates. A diverse range of drug‐relevant amine substituents can be introduced under unified reaction conditions, including primary alkyl amines, ammonia, (hetero)aromatic amines, and N‐heterocycles (see scheme).
(2
E,3Z)-2-(1-Methyl-2,5-dioxoimidazolidin-4-ylidene)-3-(arylamino- or heteroarylamino)methylenesuccinate
5 obtained by 2+2 cycloaddition of (5
...Z)-5-(dimethylamino)methylene-3-methylimidazolidine-2,4-dione (
1) and dimethyl acetylenedicarboxylate (
2) followed by substitution of the dimethylamino group with aromatic or heteroaromatic amines, afforded by heating in ethanol in the presence of potassium hydroxide, potassium salts
6. Acidification of
6 with hydrochloric acid afforded mixtures of (
E)- and (
Z)-isomers of methyl 4-(2-hydroxy-1-methyl-5-oxo-1
H-imidazol-4(5
H)-ylidene)-5-oxo-1-phenyl-4,5-dihydro-1
H-pyrrole-3-carboxylates. On the other hand, alkylation of compounds
6 with methyl iodide or benzyl bromide produced the corresponding methyl (
E)-4-(2-methoxy- or 2-benzyloxy-1-methyl-5-oxo-1
H-imidazol-4(5
H)-ylidene)-5-oxo-1-phenyl-4,5-dihydro-1
H-pyrrole-3-carboxylates
9, derivatives of a new triazafulvalene system.
Display omitted
PDF
