Conformational Complexity in Seven-Membered Cyclic Triazepinone/Open Hydrazones. 1. 1D and 2D Variable Temperature NMR Study
作者:Kalevi Pihlaja、Mario F. Simeonov、Ferenc Fülöp
DOI:10.1021/jo962322k
日期:1997.7.1
The stereo chemistry and conformational behavior of a series of 22 2-methyl-2-alkyl(phenyl, aryl)-4-N-methyl-1,2,3,4-tetrahydro-5H-1,3,4-bnezotriazepin-5-ones and their open-chain hydrazone tautomers in various solvents were studied by 1D and 2D NMR techniques in the temperature range from 193 K to 410 K. Molecular rearrangements involving interconversions of the ring and open-chain forms (the latter via amide bond and Z/E C=N double bond isomerization), pseudorotation of the ring forms, and N-inversion processes with different rates on the NMR time scale took place, leading to the observation of average and deceptively simple H-1 and C-13 NMR spectra for most of them at room temperature.