Exploiting Synergistic Catalysis for an Ambient Temperature Photocycloaddition to Pyrazoles
Sydnone-based cycloaddition reactions are a versatile platform for pyrazole synthesis, however they operate under harsh conditions (high temperature and long reaction times). Herein we report a strategy that addresses this limitation utilizing the synergistic combination of organocatalysis and visible-light photocatalysis. This new approach proceeds under ambient conditions and with excellent levels of regiocontrol. Mechanistic studies suggest that photoactivation of sydnones, rather than enamines, is key to the successful implementation of this process.
Lakeland, Christopher P.,Watson, David W.,Harrity, Joseph P. A.
supporting information
p. 155 - 159
(2019/12/11)
Synthesis and evaluation of phenyl substituted sydnones as potential DPPH-radical scavengers
A series of phenyl substituted sydnones has been synthesized and their radical-scavenging activity has been studied on DPPH free radical. Out of eighteen compounds screened, nine compounds show interesting activity. A mechanism is presented whereby sydnones scavenge DPPH radical through donating H-atom at 4th-position. Its strong radical-scavenging activity mainly arises from 1, 2, 3-oxadiazolium-5-olate ring. Different substituents and their positions on the phenyl ring differently influence DPPH scavenging activity and therefore, may provide clues to design and develop better free-radical scavenging sydnones with multiple activities.
Mallur, Shanta G.,Tiwari,Raju, B. China,Babu, K. Suresh,Ali, A. Zehra,Sastry,Rao, J. Madhusudana
p. 1686 - 1689
(2008/09/19)
Pyrimidin derivatives
The invention relates to new pharmaceutically active compounds which are are P2-purinoceptor 7-transmembrane (TM) G-protein coupled receptor antagonists, compositions containing them and processes for their preparation.
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(2008/06/13)
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