Synthesis and anti-microbial activity of some new fluorinated 1H-pyrazoles
摘要:
Several new trifluoromethyl-1H-pyrazoles were prepared by reaction of hydrazine monohydrate with 1,3-diketones. Their structures were confirmed by elemental analysis, IR, H-1 NMR and EI-MS spectroscopy. The anti-microbial activities of the newly synthesized compounds were examined by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. All the trifluoromethyl-1H-pyrazoles exhibited a certain degree of anti-bacterial and anti-fungal activities. (C) 2010 Elsevier B.V. All rights reserved.
A highlyregioselectivesynthesis of 1-aryl-3,4,5-substituted pyrazoles based on the condensation of 1,3-diketones with arylhydrazines is described. The reaction proceeds at room temperature in N,N-dimethylacetamide and furnishes pyrazoles in 59-98% yields.
First synthesis of functionalized 5-aryl-3-(trifluoromethyl)phenols by regioselective [3+3] cyclocondensations of 1,3-bis(silyloxy)-1,3-butadienes with 3-aryl-3-silyloxy-1-trifluoromethyl-2-en-1-ones
A variety of functionalized 5-aryl-3-(trifluoromethyl)phenols were prepared by the first TiCl4-mediated [3+3] cyclocondensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-aryl-3-trimethylsilyloxy-1-trifluoromethyl-2-en-1-ones.
CO2 and water are the only byproducts of this process, and the reaction conditions can scale up to gram quantities. The transformation involves an unprecedented tBuOK-catalyzed domino process, and features Michael addition/6π-electrocyclic ring opening/[1,5]-H shift/carba-6π-electrocyclic ring closure/decarboxylative aromatization reactions.
The reaction of hydroxylamine with aryl trifluoromethyl-β-diketones: Synthesis of 5-hydroxy-5-trifluoromethyl-Δ2-isoxazolines and their dehydration to 5-trifluoromethylisoxazoles
作者:Vinod Kumar、Ranjana Aggarwal、Shiv P. Singh
DOI:10.1016/j.jfluchem.2006.03.009
日期:2006.7
Reaction of hydroxylamine hydrochloride with aryl trifluoromethyl-β-diketones affords 5-hydroxy-5-trifluoromethyl-Δ2-isoxazolines rather than the reported 3-trifluoromethylisoxazoles. The structural assignment is based on the analysis of their NMR (1H, 13C and 19F) spectral data and of their dehydration products, 5-trifluoromethylisoxazoles.
An Integrated Continuous Flow Micro-Total Ultrafast Process System (μ-TUFPS) for the Synthesis of Celecoxib and Other Cyclooxygenase Inhibitors
作者:Vinay Kumar Sthalam、Ajay K. Singh、Srihari Pabbaraja
DOI:10.1021/acs.oprd.9b00212
日期:2019.9.20
Integrated continuous manufacturing has emerged as a promising device for the rapid manufacturing of active pharmaceutical ingredients (APIs). We herein report a newly designed continuous flow micro-total process system platform for the rapid manufacturing of celecoxib, a selective nonsteroidal anti-inflammatory drug. This approach has been proven generally for the synthesis of several alkyl and aryl