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Vicarious Nucleophilic Substitution (vicarious + nucleophilic_substitution)
Selected AbstractsVicarious Nucleophilic Substitution of (Chloroalkyl)oxazolines with Nitroarenes: Synthesis of (Nitrobenzyl)oxazolinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2003Saverio Florio Abstract 2-Chloroalkyloxazolines 1a and 1b react with nitroarenes in the presence of tBuOK in DMSO to give, upon acidic quenching, substituted nitroaryloxazolines 2a, 2b, 3a, 9, 10, 11a,d, 12,19, and 21,22, probably by vicarious nucleophilic substitution (VNS). The reaction of 1a is poorly regioselective, while that of 1b is completely para regioselective, thus showing that the coupling is sterically controlled. Trapping of the carbanionic intermediate B of the VNS reaction with electrophiles furnished ,,,-disubstituted (nitrobenzyl)oxazolines 4,7. Attempts to trap B with PhCHO failed: the [(p -nitrophenyl)oxazolinyl]ethanol 8 was obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Application of Vicarious Nucleophilic Substitution to the Total Synthesis of dl-Physostigmine.CHEMINFORM, Issue 49 2003Pankaj D. Rege Abstract For Abstract see ChemInform Abstract in Full Text. [source] Vicarious Nucleophilic Substitution of (Chloroalkyl)oxazolines with Nitroarenes: Synthesis of (Nitrobenzyl)oxazolinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2003Saverio Florio Abstract 2-Chloroalkyloxazolines 1a and 1b react with nitroarenes in the presence of tBuOK in DMSO to give, upon acidic quenching, substituted nitroaryloxazolines 2a, 2b, 3a, 9, 10, 11a,d, 12,19, and 21,22, probably by vicarious nucleophilic substitution (VNS). The reaction of 1a is poorly regioselective, while that of 1b is completely para regioselective, thus showing that the coupling is sterically controlled. Trapping of the carbanionic intermediate B of the VNS reaction with electrophiles furnished ,,,-disubstituted (nitrobenzyl)oxazolines 4,7. Attempts to trap B with PhCHO failed: the [(p -nitrophenyl)oxazolinyl]ethanol 8 was obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Vicarious nucleophilic amination of nitroquinolines by 1,1,1-trimethylhydrazinium iodideJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2008Maria Grzego The amination of 3-, 5-, 6-, 7- and 8-nitroquinoline via the vicarious nucleophilic substitution of hydrogen (VNS) with 1,1,1-trimethylhydrazinium iodide (TMHI) in the presence of t -BuOK in DMSO was studied. The amination occurs regioselectively giving ortho or ortho and para isomers relative to the nitro group with a high yield (95-86%). 2-Nitroquinoline does not undergo vicarious amination but displacement of the labile nitro group by an amino group occurs and then transformation to an imine compound and hydrolysis gives2(1H)-quinolinone. [source] | ||||||||||