作者:Frank G. Riddell、Eric S. Turner、Alan R. Katritzky、Ranjan C. Patel、Fernando M.S. Brito-Palma
DOI:10.1016/0040-4020(79)85033-4
日期:1979.1
The synthesis and variable temperature 1H and 13C NMR spectra of three tetrahydro-1,2,4-oxadiazines are reported. The N(4)-Me inversion barriers are 6.8–7.0 (ax→ts) and 7.4–7.9 kcal mol−1 (eq→ts) with ΔG° 0.6–0.9 kcal mol−1. The N(2)-Me inversion barriers are 10.4–11.4 (ax→ts) and 11.6–13.1 kcal mol−1 (eq→ts) with ΔGδ 1.2–1.7 kcal mol−1. The barrier to ring inversion is ca. 12.7 kcal mol−1. “R value”
报道了三种四氢-1,2,4-恶二嗪的合成及1 H和13 C NMR的可变温度光谱。N(4)-Me的反演势垒为6.8–7.0(ax→ts)和7.4–7.9 kcal mol -1(eq→ts),ΔG°为0.6–0.9 kcal mol -1。N(2)-Me反演势垒为10.4–11.4(ax→ts)和11.6–13.1 kcal mol -1(eq→ts),ΔGδ1.2–1.7 kcal mol -1。环反转的障碍大约为。12.7 kcal mol -1。“ R值”分析显示该环在C(5)-(6)键周围具有56.5±2δ二面角,表示预期的椅子构象。