Compounds with bridgehead nitrogen. 44—the conformational analysis of perhydropyrido[1,2-c] [1,3]thiazine
摘要:
AbstractThe 270 MHz NMR data on trans‐ and cis‐(H‐4a, H‐7)‐7‐ethylperhydropyrido[1,2‐c][1,3]thiazine show heavy conformational bias to the trans‐ and S‐inside cis‐fused conformations, respectively. Comparison of the 13C NMR spectra of these anancomeric systems with the 13C NMR spectrum of perhydropyrido[1,2‐c][1,3]thiazine indicates a trans‐⇌S‐inside cis‐conformational equilibrium for the latter compound in CDCl3 at 25°C, containing ca 75% trans‐fused conformer. The 13C NMR spectrum of perhydropyrido[1,2‐c][1,3]‐thiazine at −75°C showed 64% trans‐fused conformer and 36% S‐inside cis‐conformer.
Compounds with bridgehead nitrogen. 44—the conformational analysis of perhydropyrido[1,2-c] [1,3]thiazine
作者:Trevor A. Crabb、Philip A. Jupp、Yoshito Takeuchi
DOI:10.1002/mrc.1270200410
日期:1982.12
AbstractThe 270 MHz NMR data on trans‐ and cis‐(H‐4a, H‐7)‐7‐ethylperhydropyrido[1,2‐c][1,3]thiazine show heavy conformational bias to the trans‐ and S‐inside cis‐fused conformations, respectively. Comparison of the 13C NMR spectra of these anancomeric systems with the 13C NMR spectrum of perhydropyrido[1,2‐c][1,3]thiazine indicates a trans‐⇌S‐inside cis‐conformational equilibrium for the latter compound in CDCl3 at 25°C, containing ca 75% trans‐fused conformer. The 13C NMR spectrum of perhydropyrido[1,2‐c][1,3]‐thiazine at −75°C showed 64% trans‐fused conformer and 36% S‐inside cis‐conformer.
CRABB, T. A.;JUPP, P. A.;TAKEUCHI, YOSHITO, ORG. MAGN. RESON., 1982, 20, N 4, 239-241