Results 31 to 40 of about 3,742 (239)

Nano-SiO2 catalyzed three-component preparations of pyrano[2,3-d]pyrimidines, 4H-chromenes, and dihydropyrano[3,2-c]chromenes

Journal of Saudi Chemical Society, 2018
An efficient one-pot three-component procedure has been developed for the preparation of tetrahydrobenzo[b]pyrans, dihydropyrano[3,2-c]chromenes, and pyrano[2,3-d]pyrimidines using nano-SiO2 as catalyst in H2O at 70 °C.
Ebrahim Mollashahi, Mohammad Nikraftar
doaj   +1 more source

Cu-phthalocyanine Coated Hybrid Magnetic Nanoparticles: Preparation and Application in the Synthesis of Mono- and Bis pyrano[2,3-d]pyrimidinones and mono- and Bis-2-amino-4H-pyrans [PDF]

Iranian Journal of Chemistry & Chemical Engineering, 2020
In this research, Cu-phthalocyanine coated hybrid magnetic nanoparticles have been prepared in a simple method and evaluated as an efficient catalyst in the preparation of mono- and bis-pyrano[2,3-d]pyrimidinones and mono- and bis-2-amino-4H-pyrans from ...
Ali Reza Karimi, Fatemeh Bagherian, Marzie Karimi   +2 more
doaj   +1 more source

Facile one-pot synthesis of photochromic pyrans.

, 2003
[reaction: see text]. Photochromic pyrans, including [3H]naphtho[2,1-b]pyrans, [2H]naphtho[1,2-b]pyrans, indeno-fused naphtho[1,2-b]pyrans, and heteroannulated pyrans, were synthesized in excellent yields through a facile one-pot procedure by reaction of
Carreira EM, Zhao W
core   +1 more source

Iron(III)-Catalyzed Prins-Type Cyclization Using Homopropargylic Alcohol:  A Method for the Synthesis of 2-Alkyl-4-halo-5,6-dihydro-2H-pyrans

, 2016
A new Prins-type cyclization between homopropargylic alcohol and aldehydes in the presence of FeX3 to obtain 2-alkyl-4-halo-5,6-dihydro-2H-pyrans in good yield is described.
Pedro O. Miranda (2397970), Juan I. Padrón (2440633), Jaime Bermejo (2400757), David D. Díaz (2531212), Victor S. Martín (3037980)   +4 more
core   +1 more source

Recent Advances in the Synthesis of 2H-Pyrans

Molecules, 2019
In this review, we discuss the nature of the different physicochemical factors affecting the valence isomerism between 2H-pyrans (2HPs) and 1-oxatrienes, and we describe the most versatile synthetic methods reported in recent literature to access to 2HPs,
David Tejedor, Samuel Delgado-Hernández, Raquel Diana-Rivero, Abián Díaz-Díaz, Fernando García-Tellado   +4 more
doaj   +1 more source

Convenient One-Pot Synthesis of Spirooxindole-4H-pyrans in the Presence of SBA-Pr-NH2 and Evaluation of their Urease Inhibitory Activities [PDF]

Journal of Nanostructures, 2012
A simple and efficient one-pot three-component synthesis of the biologically important spirooxindole-4H-pyrans was carried out by the reaction of isatin, activated methylene reagents, and 4- hydroxycoumarin in aqueous medium. SBA-Pr-NH2 was found to be
G. Mohammadi Ziarani, N. Hosseini Mohtasham, N. Lashgari, A. Badiei, M. Amanlou, R. Bazl   +5 more
doaj   +1 more source

Chiral Cyclopentadienyl Ruthenium Complexes as Versatile Catalysts for Enantioselective Transformations

CHIMIA, 2017
Ruthenium complexes, in particular cyclopentadienyl ruthenium (??) derivatives, catalyze a vast number of transformations in the field of homogenous catalysis.
David Kossler, Nicolai Cramer
doaj   +1 more source

Nitriles in heterocyclic synthesis: Novel syntheses of benzo[b]pyrans, naphtho[1,2-b]pyrans, naphtho[2,1-b]pyrans, pyrano[3,2-h]quinolines and pyrano[3,2-c]quinolines

, 1988
Benzo[b]pyrans, naphtho[1,2-b]pyrans, naphtho[2,1-b]pyrans, pyrano[3,2-h]quinolines, and pyrano[3,2-c]quinolines were synthesized by the reaction of cinnamonitriles with phenols, naphthols, 8-hydroxyquinoline, and 1-methyl-4-hydroxy-2-quinoline.
Mohamed H. Elnagdi, Abdel Ghani A. Elagamey, Fathy M. A. El-Taweel, Salah Z. Sawllim   +3 more
core   +1 more source

Single‐Step Fabrication of Smart 3D Microstructures Exploiting Naphthopyrans as Photoinitiators and Photochromic Molecules

Advanced Optical Materials, EarlyView.
Naphthopyran–benzophenone compounds can act simultaneously as photoinitiators and photochromic molecules for two‐photon polymerization. Using a single‐step process, liquid photoresist is encapsulated within polymerized 3D microstructures, preserving reversible UV–vis photochromism after fabrication.
João P. Leote, Artur Andrishak, Paulo J. Coelho, José R. Fernandes, Christian Maibohm, Jana B. Nieder   +5 more
wiley   +1 more source

Synthesis of Fe3O4@SiO2@Pr-NH2@DAP as a magnetic recyclable nano-catalyst for efficient synthesis of pyranothiazolopyrimidines and 4H-pyrans under solvent-free condition

Scientific Reports, 2023
In this research, we describe the synthesis of silica-coated nano-Fe3O4 particles, which were successfully modified by diaminopyrimidine, and their physicochemical properties were characterized using FT-IR, XRD, TEM, FE-SEM, EDX, EDX-mapping, and TGA ...
Maryam Danehchin, Abbas Ali Esmaeili
doaj   +1 more source