63009-74-5Relevant articles and documents
General Cyclopropane Assembly by Enantioselective Transfer of a Redox-Active Carbene to Aliphatic Olefins
Montesinos-Magraner, Marc,Costantini, Matteo,Ramírez-Contreras, Rodrigo,Muratore, Michael E.,Johansson, Magnus J.,Mendoza, Abraham
, p. 5930 - 5935 (2019/02/24)
Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates, and reagents, even when targeting similar compounds. This approach slows down discovery and limits available chemical space. Introduced herein is a practical and versatile diazocompound and its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. The redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect allowed the asymmetric cyclopropanation of various olefins, including unfunctionalized aliphatic alkenes, that enables the three-step total synthesis of (?)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons.
Synthesis, characterization and in vitro evaluation of substituted N-(2-phenylcyclopropyl)carbamates as acetyl- and butyrylcholinesterase inhibitors
Horáková, Eva,Drabina, Pavel,Bro?, B?etislav,?těpánková, ?árka,Vor?áková, Katarína,Královec, Karel,Havelek, Radim,Sedlák, Milo?
, p. 173 - 179 (2016/12/16)
A serie of O-substituted N-2-phenylcyclopropylcarbamates was prepared and characterized. These carbamates were tested as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). It was found, that these compounds exhibit moderate inhibition activity with values of IC50 in the range of 54.8–94.4 μM (for AChE) and up to 5.8 μM (for BChE). The AChE/BChE selectivity for each carbamate was calculated. These values varied from 0.50 to 9.46, two carbamate derivatives inhibited only AChE selectively. The most promising derivative was prepared in all optically pure forms (four isomers). It was found that individual stereoisomers differed only slightly in the inhibition ability. The cytotoxicity of all carbamates was evaluated using the standard in vitro test with Jurkat cells. With regard to their inhibition activity and cytotoxicity as well as easy preparation, O-substituted N-2-phenylcyclopropylcarbamates can be considered as promising compounds for potential medicinal applications.
An exploratory study of ring closures of aryl radicals onto cyclopropyl- and oxiranyl-isocyanate acceptors
Minin, Patricia L.,Walton, John C.
, p. 2471 - 2475 (2007/10/03)
The idea that ring closures of C-centred radicals onto isocyanates could be made permanent by designing the cyclised radical to undergo a rapid onward β-scission, was investigated for the 2-(2-isocyanato)cyclopropylphenyl and 2-(2-isocyanato)oxiranylphenyl radicals. The radical precursors, trans- and cis-l-bromo-(2-isocyanatocyclopropyl)benzene and (2-bromophenyl)-3- isocyanatooxirane, were prepared from the corresponding bromophenylcyclopropane and bromophenyloxirane carboxylic acids via Curtius rearrangements of the derived azides. The structure of the trans-2-(2-isocyanato)cyclopropylphenyl radical prevents cyclization, however, it was shown that isomerisation to the analogous cis-radical occurred, probably by scission of the disubstituted cyclopropane bond followed by internal rotation of the resulting resonance stabilised diradical. It was found, however, that the main product from homolytic reactions of both trans- and cis-isocyanatocyclopropyl compounds, with tributyltin hydride and tris(trimethylsilyl)silane, was the direct reduction product, trans-(2-isocyanatocyclopropyl)benzene. Only traces of cyclised products, that were probably 4,5-dihydrobenzo[c]azepin-1-one from the cyclopropane precursor and 5H-6-oxa-8-azabenzocyclohepten-9-one from the oxirane precursor, were detected. We conclude, therefore, that the rate of cyclization onto isocyanate acceptor groups must be slower in these systems than hex-5-enyl cyclization or that the reverse ring-opening process must be faster than for analogous radicals.
Catalytic cyclopropanation of alkenes using diazo compounds generated in situ. A novel route to 2-arylcyclopropylamines
Aggarwal, Varinder K.,De Vicente, Javier,Bonnert, Roger V.
, p. 2785 - 2788 (2007/10/03)
(Equation presented) A user-friendly, one-pot process for catalytic cyclopropanation of alkenes from tosylhydrazones is described. The cyclopropanation of N-vinylphthalimide provides a new route to 2-arylcyclopropylamines, and this is exemplified in the efficient synthesis of the HIV-1 reverse transcriptase inhibitor 6.
