γ-Maghemite-silica nanocomposite: A green catalyst for diverse aromatic N-heterocycles
摘要:
gamma-Maghemite-silica nanocomposite has been applied as a green catalyst to synthesize variety of aromatic N-heterocycles under solvent free conditions. Characterization was done by modern analytical tools (UV, IR, AAS, DSC, EDXRF, powdered XRD, EPR, Mossbauer and TEM). Mild reaction conditions and recyclability have made the present protocol both environmentally and economically viable. (c) 2013 Elsevier B.V. All rights reserved.
Synthesis of Sterically Hindered Primary Amines by Concurrent Tandem Photoredox Catalysis
作者:Michael C. Nicastri、Dan Lehnherr、Yu-hong Lam、Daniel A. DiRocco、Tomislav Rovis
DOI:10.1021/jacs.9b10871
日期:2020.1.15
methodologies exist for amine synthesis, but the direct synthesis of primary amines with a fully substituted α carbon center is an underdeveloped area. We report a method which utilizes photoredox catalysis to couple readily available O-benzoyl oximes with cyanoarenes to synthesize primary amines with fully substituted α-carbons. We also demonstrate that this method enables the synthesis of amines with α-trifluoromethyl
Irradiation of an acetonitrile solution containing 2,3-dicyano-5,6-diphenylpyrazine with allylic silanes, benzylsilane, and ketene silyl acetal gave the mono-substituted products in excellent yields. This reaction is useful for the functionalization of pyrazine ring.
Quaternary Stereogenic Centers through Enantioselective Heck Arylation of Acyclic Olefins with Aryldiazonium Salts: Application in a Concise Synthesis of (<i>R</i>)-Verapamil
作者:Caio C. Oliveira、Andreas Pfaltz、Carlos Roque Duarte Correia
DOI:10.1002/anie.201507927
日期:2015.11.16
all‐carbon quaternary stereogenic centers. Chiral N,N ligands of the pyrimidine‐ and pyrazino‐oxazoline class were developed for that purpose, providing the desired products in good to high yields with enantiomeric ratios up to >99:1. Both linear and branched substituents on the olefins were well‐tolerated. The potential of this new method is demonstrated by the straightforward synthesis of several
Electrochemical Synthesis of Hindered Primary and Secondary Amines via Proton-Coupled Electron Transfer
作者:Dan Lehnherr、Yu-hong Lam、Michael C. Nicastri、Jinchu Liu、Justin A. Newman、Erik L. Regalado、Daniel A. DiRocco、Tomislav Rovis
DOI:10.1021/jacs.9b10870
日期:2020.1.8
Accessing hindered amines, particularly primary amines α to a fully substituted carbon center, is synthetically challenging. We report an electrochemical method to access such hindered amines starting from benchtop-stable iminium salts and cyanoheteroarenes. A wide variety of substituted heterocycles (pyridine, pyrimidine, pyrazine, purine, azaindole) can be utilized in the cross-coupling reaction
Subphthalocyanine azaanalogues – Boron(III) subporphyrazines with fused pyrazine fragments
作者:Pavel A. Stuzhin、Ivan A. Skvortsov、Yuriy A. Zhabanov、Nikolai V. Somov、Oleg V. Razgonyaev、Ivan A. Nikitin、Oskar I. Koifman
DOI:10.1016/j.dyepig.2018.11.006
日期:2019.3
Pyrazine fused subporphyrazines exhibit strong absorption bands at 300–310 and 530–550 nm. The phenyl substituted derivative [Ph6Pyz3sPABCl] has an additional intense charge transfer band at 390 nm and can be reversibly reduced at −0.81 V (vs Ag/AgCl in MeCN). The influence of pyrazine rings on the geometrical and electronic structural features and spectral properties of subporphyrazine dye was also