作者:Li Wen、Seth C. Rasmussen
DOI:10.1007/s10870-006-9160-y
日期:2007.6
Using new nitration protocols, we have been able to efficiently dinitrate 2,5-dihalothiophenes with yields of ∼80–95%. The resulting products 2,5-dibromo-3,4-dinitrothiophene (1), 2,5-dichloro-3,4-dinitrothiophene (2), 2-bromo-5-chloro-3,4-dinitrothiophene (3), as well as the analogous 2-bromo-3,4-dinitrothiophene (4), all crystallize easily allowing their characterization via X-ray crystallography. Crystallization of 1 occurs in the monoclinic space group C2/c with a = 14.547(3) Å, b = 7.3534(15) Å, c = 10.775(2) Å, β = 128.89(3)°, and Z = 4. Crystallization of 2 occurs in the tetragonal space group I-42d with a = 9.9398(14) Å, b = 9.9398(14) Å, c = 16.866(3) Å, and Z = 8. Crystallization of 3 occurs as a pseudo-merohedral twin in the triclinic space group P-1 with a = 7.340(5) Å, b = 8.094(5) Å, c = 9.112(5) Å, α = 82.059(5)°, β = 66.232(5)°, γ = 63.021(5)°, and Z = 2. Crystallization of 4 occurs in the triclinic space group P-1 with a = 7.1787(14) Å, b = 7.4092(15) Å, c = 8.3151(17) Å, α = 101.67(3)°, β = 96.00(3)°, γ = 116.13(3)°, and Z = 2. The structures of all compounds exhibit the formation of interesting solid-state assemblies due to halogen-bonding interactions between the halogen and nitro groups.
通过使用新的硝化方案,我们能够高效地对 2,5-二卤噻吩进行二硝化反应,产率可达 ∼ 80-95%。所得产物 2,5-二溴-3,4-二硝基噻吩 (1)、2,5-二氯-3,4-二硝基噻吩 (2)、2-溴-5-氯-3,4-二硝基噻吩 (3) 以及类似的 2-溴-3,4-二硝基噻吩 (4),都很容易结晶,可以通过 X 射线晶体学进行表征。1 结晶于单斜空间群 C2/c,a = 14.547(3) 埃,b = 7.3534(15) 埃,c = 10.775(2) 埃,β = 128.89(3)°,Z = 4。2 在 I-42d 四方空间群中结晶,a = 9.9398(14) 埃,b = 9.9398(14) 埃,c = 16.866(3) 埃,Z = 8。3 在三菱空间群 P-1 中结晶为假正四面体孪晶,a = 7.340(5) 埃,b = 8.094(5) 埃,c = 9。4 在三菱空间群 P-1 中结晶,a = 7。1787(14) 埃,b = 7.4092(15) 埃,c = 8.3151(17) 埃,α = 101.67(3)°,β = 96.00(3)°,γ = 116.13(3)°,Z = 2。由于卤素和硝基之间的卤键相互作用,所有化合物的结构都显示出形成了有趣的固态组合体。