A Unified Continuous Flow Assembly-Line Synthesis of Highly Substituted Pyrazoles and Pyrazolines
作者:Joshua Britton、Timothy F. Jamison
DOI:10.1002/anie.201704529
日期:2017.7.17
molecular diversity in short order. Continuous flowsynthesis enables the safe handling of diazoalkanes at elevated temperatures, and the use of aryl alkyne dipolarphiles under catalyst-free conditions. This assembly-line synthesis provides a flexible approach for the synthesis of agrochemicals and pharmaceuticals, as demonstrated by a four-step, telescoped synthesis of measles therapeutic, AS-136A, in a total
Fluoroalkyl-Substituted Diazomethanes and Their Application in a General Synthesis of Pyrazoles and Pyrazolines
作者:Lucas Mertens、Katharina J. Hock、Rene M. Koenigs
DOI:10.1002/chem.201601707
日期:2016.7.4
A novel continuous‐flow approach for the synthesis of fluoroalkyl‐substituted diazomethanes has been developed. Utilizing a cheap, self‐made microreactor fluoroalkyl‐substituted amines were transformed into the corresponding diazomethanes using tert‐butyl nitrite and acetic acid as catalyst. These diazomethanes were employed in [2+3] cycloaddition reactions with olefins and alkynes, yielding valuable
In Situ Generation of Difluoromethyl Diazomethane for [3+2] Cycloadditions with Alkynes
作者:Pavel K. Mykhailiuk
DOI:10.1002/anie.201501529
日期:2015.5.26
A novel approach to agrochemically important difluoromethyl‐substituted pyrazoles has been developed based on the elusive reagent CF2HCHN2, which was synthesized (generated in situ) for the first time and employed in [3+2] cycloaddition reactions with alkynes. The reaction is extremely practical as it is a one‐pot process, does not require a catalyst or the isolation of the potentially toxic and explosive
Synthesis of <i>N</i>
-Nitroso CHF<sub>2</sub>
-Pyrazolines and Their Transformation into CHF<sub>2</sub>
-Isoxazolines and -Pyrazoles
作者:Pavlo S. Lebed、Johan Fenneteau、Yong Wu、Janine Cossy、Pavel K. Mykhailiuk
DOI:10.1002/ejoc.201700803
日期:2017.11.9
N-Nitroso CHF2-pyrazolines were synthesized from in situ generated difluoromethyldiazomethane (CF2HCHN2), tert-butyl isonitrite (tBuONO), and alkenes. The synthesis of representative CHF2-pyrazoles and CHF2-oxazolines was also performed.
Synthesis of Celecoxib, Mavacoxib, SC-560, Fluxapyroxad, and Bixafen Enabled by Continuous Flow Reaction Modules
作者:Joshua Britton、Timothy F. Jamison
DOI:10.1002/ejoc.201700992
日期:2017.12.1
Multi-step continuousflowsynthesisenables a parallel approach to obtain agrochemicals and pharmaceuticals containing 3-fluoroalkyl pyrazole cores. In this system, fluorinated amines are transformed into pyrazole cores through a telescoped in situ generation and consumption of diazoalkanes. Once synthesized, additional continuousflow and batch reactions add complexity to the pyrazole core via C–N