142942-63-0Relevant articles and documents
An investigation of the rotational isomers of N-acetyl-2,2-dimethyloxazolidine and related compounds by nuclear magnetic resonance spectroscopy and molecular mechanics
Taylor, Wesley G.,Hall, Tse Wai,Schreck, Carl E.
, p. 165 - 172 (2007/10/02)
The 15 2,2-dimethyloxazolidines described here were found to exist in solution predominantly as a single rotational isomer, unlike N-acetyloxazolidine (1), N-acetyl-2-methyloxazolidine (2), N-acetyl-2-(n-octyl)oxazolidine (3), and other known 2-substituted N-acyloxazolidines.Using 13C NMR spectroscopy, activation energies for interconversion of the E (minor) and Z (major) rotational isomers of 1-3 were determined from coalescence temperature measurements in pyridine-d5.A sample of N-acetyl-2,2-dimethyloxazolidine (4) was isolated for comparison.The rotational isomer of 4 was found by two-dimensional nuclear Overhauser effect spectroscopy (NOESY) to possess the Z (or trans) stereochemistry.Molecular mechanics (MMX) calculations on the E and Z isomers of 1-4 helped to account for these findings.The conformation of the energy-minimized structures resemble a C-5 envelope.Samples of N-aroyl-2,2-dimethyloxazolidines (5a-5n) were isolated and the rotational isomers were assigned the Z stereochemistry by NOESY and 13C NMR experiments.Most of these 2,2-dimethyloxazolidines were ineffective in a bioassay for mosquito repellent activity. Key words: N-acyloxazolidines, N-aroyloxazolidines, NMR spectroscopy, rotational isomerism, molecular mechanics.
