Crystal and Molecular Structure of 2,3,5,6-Bis(ortho-1,10-decylidene)dihydropyrazine  

作　　者：WANG Ming-An ZHANG Ning HOU Xue-Tai WANG Dao-Quan 

机构地区：[1]Department of Applied Chemistry, China Agricultural University, Beijing 100094, China

出　　处：《Chinese Journal of Structural Chemistry》2005年第11期1254-1258,共5页结构化学（英文）

基　　金：This project was supported by the National Natural Science Foundation of China (No. 20072053)

摘　　要：The SnCl2 reduction of 2-nitrocyclododecanone or 2-bromo-12-nitrocyclododecanone gave a colorless compound 2,3,5,6-bis（ortho-1,10-decylidene）dihydropyrazine 1a characterized by IR, NMR and X-ray diffraction analysis. Crystal data for 1a： Mr = 358.60, monoclinic, space group P2 1/n, α = 0.48028（3）, b = 2.8646（4）, c = 0.77097（6） nm, β = 98.432（12）°, V = 1.04924（19） nm^3, Dc = 1.135 g/cm^3, Z = 2, F（000） = 400 and μ（MoKa） = 0.065 mm^-1. All ^1H- and ^13C-NMR resonance lines of 1a were assigned by DEPT, COSY, HMQC and HMBC technology. In the crystal, the dihydropyrazine ring has a planar structure, two twelve-membered tings adopt [lene2333] conformation, their double bonds have cis-configuration, and the whole molecule has a center of symmetry. In solution, the symmetric ^1H- and ^13C-NMR signals suggest that two twelve-membered rings of 1a may adopt enantiomorphous [ lene2333] conformation existing in a dynamic equilibrium.The SnCl2 reduction of 2-nitrocyclododecanone or 2-bromo-12-nitrocyclododecanone gave a colorless compound 2,3,5,6-bis（ortho-1,10-decylidene）dihydropyrazine 1a characterized by IR, NMR and X-ray diffraction analysis. Crystal data for 1a： Mr = 358.60, monoclinic, space group P2 1/n, α = 0.48028（3）, b = 2.8646（4）, c = 0.77097（6） nm, β = 98.432（12）°, V = 1.04924（19） nm^3, Dc = 1.135 g/cm^3, Z = 2, F（000） = 400 and μ（MoKa） = 0.065 mm^-1. All ^1H- and ^13C-NMR resonance lines of 1a were assigned by DEPT, COSY, HMQC and HMBC technology. In the crystal, the dihydropyrazine ring has a planar structure, two twelve-membered tings adopt [lene2333] conformation, their double bonds have cis-configuration, and the whole molecule has a center of symmetry. In solution, the symmetric ^1H- and ^13C-NMR signals suggest that two twelve-membered rings of 1a may adopt enantiomorphous [ lene2333] conformation existing in a dynamic equilibrium.

关 键 词：2 3 5 6-bis（ortho-1 10-decylidene）dihydropyrazine crystal structure NMR 

分 类 号：O626.4[理学—有机化学]