Results 71 to 80 of about 2,558 (239)

Preparation of 3,5-Disubstituted Pyrazoles and Isoxazoles from Terminal Alkynes, Aldehydes, Hydrazines, and Hydroxylamine

, 2016
The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with ...
Hideo Togo (1418257), Ryo Harigae (1837285), Katsuhiko Moriyama (1418254)   +2 more
core   +2 more sources

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

Beilstein Journal of Organic Chemistry
For the first time, the interaction of aroyl containing pyrano[2,3-d]isoxazolone derivatives with various hydrazines was studied. It was shown that the considered process includes formation of corresponding hydrazones followed by Boulton–Katritzky ...
Constantine V. Milyutin, Andrey N. Komogortsev, Boris V. Lichitsky   +2 more
doaj   +1 more source

Síntese e avaliação preliminar da atividade antinociceptiva de novas isoxazolil-aril-hidrazonas

Química Nova, 2011
New 2-isoxazoline aldehydes were synthesized, in good yields, from cycloadduct of the 1,3-dipolar cycloaddition reaction between endocyclic enecarbamate and carboethoxyformonitrile oxide (CEFNO). Condensation of these 2-isoxazoline aldehydes with several
Sílvio Leandro Gonçalves Bomfim Reis, Valderes Moraes de Almeida, Gleybson Correia de Almeida, Karinna Moura Boaviagem, Charles Christophe Du Barriere Mendes, Antônio Rodolfo de Faria, Alexandre José da Silva Góes, Laudelina Rodrigues Magalhães, Teresinha Gonçalves da Silva   +8 more
doaj   +1 more source

Nucleophilic Reactivities of Hydrazines and Amines: The Futile Search for the α‑Effect in Hydrazine Reactivities

, 2016
The kinetics of the reactions of amines, hydrazines, hydrazides, and hydroxylamines with benzhydrylium ions and quinone methides were studied in acetonitrile and water by UV–vis spectroscopy, using conventional spectrometers and stopped-flow and laser ...
Anna Antipova (2041855), Herbert Mayr (1353507), Tobias A. Nigst (2041858)   +2 more
core   +1 more source

Chemoselective synthesis of 1,3,4-thiadiazoles from acyl hydrazines and nitroalkanes using elemental sulfur

Nature Communications
Substituted 1,3,4-thiadiazoles find extensive use in pharmaceutical, agricultural, and materials chemistry. The incorporation of adaptable heterocyclic pharmacophores results in tunable hybrid molecules with diverse medicinal properties.
Xiaonan Wang, Xiuwen Yu, Ruixi Qian, Silong Xu, Martin J. Lear, Wangxiao He, Jing Li   +6 more
doaj   +1 more source

Oxidized Phenyl−Substituted Sesquibicyclic Hydrazines

, 1995
The effect of a− and P−phenyl substituents on the neutral, +1, and +2 oxidation states of bis−N,N'− bicyclic hydrazines 1 and 2 is discussed. An a−phenyl substituent on 2 makes first electron removal 1.8 kcal/mol more difficult, but second electron ...
Nelsen, S., Nelsen, Stephen F., Neugebauer, Franz A., Neugebauer, F., Hiyashi, R., Powell, Douglas R., Powell, D., Wang, Yichun, Hiyashi, Randy K., Wang, Y.   +9 more
core   +1 more source

Solid acidic FeCl3/Bentonite catalyzed solvent-free condensation: Synthesis, spectral studies and antimicrobial activities of some aryl hydrazine Schiff’s bases

, 2016
Some aryl hydrazide derivatives have been synthesized including 1-(3-chloro-4-nitrophenyl)-2-(3-substituted benzylidene) hydrazines by  FeCl3/Bentonite catalyzed solvent-free  condensation of  substituted phenyl hydrazine and aldehydes under microwave ...
Ananthi, Vadamalai, Rajalakshmi, Kaliyaraj, Muthuvel, Inbasekaran, Thirunarayanan, Ganesamoorthy   +3 more
core   +1 more source

Toward Chromoselective Transformations in Biological Systems: Perspectives and Challenges

Angewandte Chemie International Edition, EarlyView.
Controlling biological systems with small‐molecule chromophores has evolved into a powerful strategy and is applied from chemical biology to medicine. However, the complexity of in vivo systems cannot be matched by a single wavelength of light. Developing methods to combine and individually control multiple chromophores is crucial.
Nadja A. Simeth
wiley   +1 more source

Novel biodegradable protonic ionic liquid for the Fischer indole synthesis reaction

Green Chemistry Letters and Reviews, 2016
Novel eco-friendly tetramethylguanidinium propanesulfonic acid trifluoromethylacetate ([TMGHPS][TFA]) ionic liquid was developed as catalyst and medium for the Fischer indole synthesis of a wide variety of hydrazines and ketones. The indole products were
William C. Neuhaus, Ian J. Bakanas, Joseph R. Lizza, Charles T. Boon, Gustavo Moura-Letts   +4 more
doaj   +1 more source

Microwave-Assisted Synthesis of Some 3,5-Arylated 2-Pyrazolines

Molecules, 2003
Condensation of 2-acetylnaphthalene with benzaldehydes under microwave irradiation affords chalcones which undergo facile and clean cyclizations with hydrazines RNHNH2 (R= H, Ph, Ac) to afford 3,5-arylated 2-pyrazolines in quantitative yields, also under
Hassan Ghasemnejad, Davood Azarifar
doaj   +1 more source