Crystal structures of 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-nitro-cyclohexa-2,4-dienone hydrate and 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-bromo-cyclohexa-2,4-dienone
摘要:
6-[(2-羟基-1,1-双-羟甲基-乙基氨基)-亚甲基]-4-硝基-环六-2,4-二烯酮水合物(I)和6-[(2-羟基-1)的晶体结构,1-双-羟甲基-乙氨基)-亚甲基]-4-溴-环己-2,4-二烯酮(II)已被测定。 I的晶体为单斜晶系,a = 16.957(1) Å,b = 10.729(2) Å,c = 7.240(3) Å; β = 99.56(3)°,空间群 P21/c,Z = 4,R = 0.0492。 II晶体为三斜晶系,a = 10.282(2) Å,b = 7.189(3) Å,c = 16.831(3) Å; α=90.67(3)°,β=100.10(3)°,γ=95.87(3)°;空间群 P-1,Z = 4,R = 0.0591。 I 晶胞的独立部分包含一个独特的分子和结晶水,而 II 中包含两个独特的分子 A 和 B。分子 B 的 C(CH2OH)3 片段体现了醇氧原子的无序性。在 I 和 II 中,分子的水杨基片段均以醌型互变异构形式存在。
Imine or Enamine? Insights and Predictive Guidelines from the Electronic Effect of Substituents in H-Bonded Salicylimines
作者:R. Fernando Martínez、Esther Matamoros、Pedro Cintas、Juan C. Palacios
DOI:10.1021/acs.joc.0c00130
日期:2020.5.1
Imine and enamine bonds decorate the skeleton of numerous reagents, catalysts, and organic materials. However, it is difficult to isolate at will a single tautomer, as dynamic equilibria occur easily, even in the solid state, and are sensitive to electronic and steric effect, including π-conjugation and H-bonding. Here, using as model Schiff bases generated from salicylaldehydes and TRIS in a set of