Reaction of o-phenylenediamine with 2,3-dichloromaleic anhydride: synthesis of N-substituted maleimide derivatives and 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one. X-ray structures of 2,3-dichloro-N-o-C6H4(NH2)maleimide and N, N?-o-C6H4-bis(2,3-dichloromaleimide)
作者:William H. Watson、Guanmin Wu、Michael G. Richmond
DOI:10.1007/s10870-004-7651-2
日期:2004.11
Refluxing equimolar amounts of 2,3-dichloromaleic anhydride and o-phenylenediamine in toluene affords the three compounds 2,3-dichloro-N-o-C6H4(NH2)maleimide (1), N,N′-o-C6H4-bis(2,3-dichloromaleimide) (2), and 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one (3). Under these conditions the former compound is observed as the major product. Repeating the same reaction in the presence of added PTSA furnishes the heterocyclic compound 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one, as the major product. Treatment of compound 1 with PTSA, coupled with water removal, gives compound 3 in near quantitative yield and confirms the intermediacy of 1 en route to 3. The new compounds 1–3 have been isolated by column chromatography and characterized in solution by spectroscopic methods. The molecular structures of the maleimide-substituted compounds 1 and 2 were determined by X-ray crystallography. 2,3-Dichloro-N-o-C6H4(NH2)maleimide crystallizes in the monoclinic space group P21/c, a = 20.693(8) Å, b = 5.712(2) Å, c = 8.787(4) Å, β = 92.819(7)°, V = 1037.3(7) Å3, Z = 4, and dcalc = 1.646 Mg/m3; R = 0.0604, Rw = 0.1140 for 1354 reflections with I > 2 σ (I), with N,N′-o-C6H4-bis(2,3-dichloromaleimide) crystallizing in the triclinic space group P−1, a = 7.9509(4) Å, b = 10.2532(6) Å, c = 12.1126(7) Å, α = 82.637(1)°, β = 87.799(1)°, γ = 71.634(1)°, V = 929.42(9) Å3, Z = 2, and dcalc = 1.651 Mg/m3; R = 0.0499, Rw = 0.1545 for 1977 reflections with I > 2σ (I).
将等摩尔量的 2,3-二氯马来酸酐和邻苯二胺在甲苯中回流,得到三种化合物 2,3-二氯-N-o-C6H4(NH2)马来酰亚胺 (1)、N,N'-o-C6H4-bis(2, 3-二氯马来酰亚胺)(2)和2,3-二氯吡咯并[1,2-a]苯并咪唑-1-酮(3)。在这些条件下,观察到前一种化合物是主要产物。在添加的PTSA存在下重复相同的反应提供杂环化合物2,3-二氯吡咯并[1,2-a]苯并咪唑-1-酮,作为主要产物。用 PTSA 处理化合物 1,再加上除水,以接近定量的收率得到化合物 3,并证实了 1 在生成 3 的过程中的中间体。新化合物 1-3 已通过柱色谱法分离,并通过光谱方法在溶液中进行表征。通过X射线晶体学测定了马来酰亚胺取代的化合物1和2的分子结构。 2,3-二氯-N-o-C6H4(NH2)马来酰亚胺在单斜空间群 P21/c 中结晶,a = 20.693(8) Å, b = 5.712(2) Å, c = 8.787(4) Å, β = 92.819 (7)°,V = 1037.3(7) Å3,Z = 4,dcalc = 1.646 Mg/m3; R = 0.0604,Rw = 0.1140,1354 次反射,I > 2 σ (I),N,N′-o-C6H4-bis(2,3-二氯马来酰亚胺) 在三斜空间群 P−1 中结晶,a = 7.9509 (4) Å, b = 10.2532(6) Å, c = 12.1126(7) Å, α = 82.637(1)°, β = 87.799(1)°, γ = 71.634(1)°, V = 929.42(9) ) Å3,Z = 2,dcalc = 1.651 Mg/m3;对于 1977 年反射,I > 2σ (I),R = 0.0499,Rw = 0.1545。