Results 11 to 20 of about 2,222 (186)

Nano-SiO2/DBN: an efficacious and reusable catalyst for one-pot synthesis of tetrahydrobenzo[b]pyran derivatives

BMC Chemistry, 2021
Background The nano-sized particles enhance the exposed surface area of the active part of the catalyst, thereby increasing the contact between precursors and catalyst considerably. In this study, nano-SiO2/1,5-diazabicyclo[4.3.0]non-5-en was synthesized,
Maryam Mehravar, Bi Bi Fatemeh Mirjalili, Elaheh Babaei, Abdolhamid Bamoniri   +3 more
doaj   +1 more source

EFFECT OF PYROLYSIS HEATING RATE ON THE CHEMICAL COMPOSITION OF WOOD VINEGAR FROM EUCALYPTUS UROGRANDIS AND MIMOSA TENUIFLORA [PDF]

Revista Árvore, 2020
Among the parameters used in the biomass carbonization process, the heating rate is one of the most important. The objective of the present work was to assess the influence of different heating rates on the chemical composition of wood vinegar (WV) from ...
Lúcio César Dantas de Medeiros, Alexandre Santos Pimenta, Renata Martins Braga, Tatiane Kelly de Azevedo Carnaval, Pedro Nico Medeiros Neto, Dulce Maria de Araújo Melo   +5 more
doaj   +1 more source

Iodine-Catalyzed Prins Cyclization of Homoallylic Alcohols and Aldehydes

Molecules, 2013
The iodine-catalyzed Prins cyclization of homoallylic alcohols and aldehydes was investigated under metal-free conditions and without additives. Anhydrous conditions and inert atmosphere are not required.
Luiz F. Silva, Erick L. Bastos, Antônio C. Doriguetto, Kachi R. Kishore Kumar Reddy, Iara M. L. Rosa   +4 more
doaj   +1 more source

Synthesis of novel tetrahydroquinoline derivatives from α,α′-bis(substituted-benzylidene)cycloalkanones

Journal of Saudi Chemical Society, 2016
In this paper, we describe a two-step synthesis of a series of substituted tetrahydroquinoline analogies. In the first step α,α′-bis(substituted-benzylidene)cycloalkanones are reacted with malononitrile to afford 2-amino-3-cyano-4H-pyrans.
Enayatollah Sheikhhosseini, Elinaz Farrokhi, Mohammad Ali Bigdeli   +2 more
doaj   +1 more source

Populene D Analogues: Design, Concise Synthesis and Antiproliferative Activity

Molecules, 2012
An efficient and concise synthesis of nine populene D analogues was performed using an iodine-catalyzed Prins cyclization as the key transformation.
Kachi R. Kishore Kumar Reddy, Giovanna B. Longato, João E. de Carvalho, Ana L. T. G. Ruiz, Luiz F. Silva, Jr.   +4 more
doaj   +1 more source

One-pot, three-component, selective synthesis of the polyfunctionalized 4H-pyran and 4H-benzo[b]pyran derivatives in the presence of a highly efficient molecular sieve-supported zinc catalyst

Green Processing and Synthesis, 2018
A series of pentasubstituted 4H-pyrans and tetrahydrobenzo[b]pyrans are synthesized with excellent yields via a one-pot condensation of aromatic aldehydes, malononitrile, and a dicarbonyl compound, ethyl acetoacetate, acetyl-acetone or dimedone, in the ...
Magyar Ágnes, Hell Zoltán
doaj   +1 more source

Computational Study on the Acid Catalyzed Reactions of Fluorine-Containing 2,4-Dialkoxy-3,4-dihydro-2H-pyrans with Aromatic Compounds

Applied Sciences, 2012
The reaction of 2,4-diethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyran (1) with aromatic compounds in refluxing acetonitrile in the presence of p-toluenesulfonic acid gave the mixture of 4-aryl-2-trifluoromethyl-4H-pyrans (3) and 6-aryl-1,1,1-trifluorohexa ...
Norio Ota, Yasuhiro Kamitori, Ryusuke Shirai, Mizuki Hatakenaka, Etsuji Okada   +4 more
doaj   +1 more source

Anisotropic NMR as a Crucial Tool for Differentiation of Epimers With High Conformational Flexibility

Angewandte Chemie, EarlyView.
Epimer discrimination remains challenging due to subtle NMR differences. Here, we propose a methodology based on 13C‐RCSA and RDC anisotropic parameters, enabling the assignment of two flexible tetraprenyltoluquinol epimers (1a and 1b) with remote stereoclusters.
Juan Carlos C. Fuentes‐Monteverde, Abel M. Forero, Nilamoni Nath, Antonio Hernández Daranas, Carlos Jiménez, Jaime Rodríguez, Christian Griesinger   +6 more
wiley   +2 more sources

Direct δ‐Lactone Synthesis From Free Alcohols via Photoinduced δ‐C(sp3)–H Carbonylation in Flow

Angewandte Chemie, EarlyView.
Herein, we have developed a photo‐flow platform for the δ‐C(sp3)─H carbonylative lactonization of free alcohols with carbon monoxide. The transformation integrates alkoxyl radical generation, selective 1,5‐HAT, CO incorporation, and radical–polar crossover to enable direct access to δ‐lactones from simple alcohol precursors.
Prakash Chandra Tiwari, Runkang Liu, Timothy Noël   +2 more
wiley   +2 more sources

Triphenylphosphine Catalysed Facile Multicomponent Synthesis of 2-Amino-3-Cyano-6-Methyl-4-Aryl-4H-Pyrans [PDF]

Iranian Journal of Chemistry & Chemical Engineering, 2017
Triphenyl phosphine(PPh3), an efficient and reusable catalyst, catalysed the synthesis of 2-amino-3-cyano-6-methyl-4-aryl-4H-pyran-5-ethylcarboxylate derivatives by one-pot condensation of aromatic aldehydes, malononitrile and ethyl acetoacetate in EtOH ...
Harikrishnan Ramadoss, Hamzeh Kiyani, Syed Sheik Mansoor   +2 more
doaj