Synthesis and dynamic NMR study of ketenimines derived from tert-butyl isocyanide, alkyl 2-arylamino-2-oxo-acetates, and dialkyl acetylenedicarboxylates.
The adduct produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by alkyl 2-arylamino-2-oxo-acetates. When the aryl group is 2-methyl-6-nitrophenyl or 2,6-di-isopropylphenyl, the product exists as two stable rotamers at room temperature as a result of restricted rotation around the Ar-N single bond. When the aryl group is 1-naphthyl or 8-quinolinyl, dynamic NMR effects are observed in the 1H NMR spectra. The calculated free-energy of activation for interconversion of the rotational isomers in 1-naphthyl and 8-quinolinyl derivatives amounts to about 99+/-2 and 68.5+/-2 kJ mol(-1), respectively.
Yavari
Issa
I
Department of Chemistry, University of Tarbiat Modarres, Tehran, Iran. isayavar@yahoo.com
Nasiri
Farough
F
Djahaniani
Horieh
H
D000085:Acetates / Q000737:chemistry*; D007097:Imines / Q000138:chemical synthesis* / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008962:Models, Theoretical; D009570:Nitriles / Q000737:chemistry*; D013053:Spectrophotometry; D013816:Thermodynamics; D013997:Time Factors
D000085:Acetates; D007097:Imines; D009570:Nitriles; C099535:tert-butyl isocyanide