摘要
通过α-单取代环十二酮与亚硝酰氯反应合成了一系列α-单取代-1,2-环十二二酮单肟,它们的结构经1H NMR,13C NMR,ESI-MS和元素分析确证.X射线衍射和量子力学计算结果表明,α-单取代环十二酮与亚硝酰氯反应生成α-单取代-1,2-环十二二酮单肟时,生成产物具有[4233]-3-酮和[3333]-2-酮两种不同类型的优势构象,α-取代基位于边碳外向位或角碳反向位,两种构象中C=N双键和羰基均处在边碳上,位于环的两侧,它们的二面角介于162°～174°之间,肟的C=N双键均为E式,两种不同的低能构象在溶液中可以通过C2-假旋相互转化,在形成晶体的过程中则分别采取能量最低的优势构象.结构特征分析表明,p-π和π-π相互作用可能是导致α-取代-1,2-环十二二酮单肟的十二元环骨架构象改变的主要因素.
A series of-monosubstituted cyclododecan-1,2-dione monooxime were prepared by the reac-tion of-monosubstituted cyclododecanone and nitrosyl chloride,and their structures were confirmed by the 1H NMR,13C NMR,ESI-MS and elemental analysis data.X-ray diffraction and quantum mechanics calcula-tion results showed that the products take two different -3-one and -2-one conformation,-substituted groups present at-side-exo or-corner-anti position,the C=N and C=O double bonds pre-sent at side chain with the torsion angles in the range of 162°～174,and the C=N double bond of oximes have E-configuration when they are synthesized with the reaction of-monosubstituted cyclododecanone and nitrosyl chloride.These two different conformations exist in a dynamic equilibrium with the C2-pseudorotation transferring pathway in the solution,and the preferred conformation was taken when it crystallized from the solution.The analysis of structure characteristics indicated that p-and-interaction may be the main factor which makes the skeleton conformation change of the twelve-membered ring of-monosubstituted cyclododecan-1,2-dione monooxime.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2011年第11期1354-1360,共7页
Acta Chimica Sinica
基金
国家自然科学基金(Nos.20772150
20072053)
教育部留学回国基金资助项目
关键词
α-单取代-1
2-环十二二酮单肟
X射线衍射
量子力学计算
构象分析
-monosubstituted cyclododecan-1
2-dione monooxime
X-ray diffraction
quantum mechanics calculation
conformation analysis
