1. Studies on the NMR Spectra and the X-ray Single Crystal Structure of Sydnone Compound

• Main Author: 何桂華
• Other Authors: 葉茂榮
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/63847607238034770531

碩士 === 國立成功大學 === 化學學系 === 83 === 　　This paper study the 13C, 15N and 17O NMR specta of sydnone, The X-ray structure of different sydnone were also examed, A novel synthesis of sydnone nitrile oxides was discovered. The peaction of sydnone nitrile oxides with unsaturated C-C bond to prepare 23 kinds of new conmpounds. The detail was showed as following. 　　First, Base on the bserved incorporation of13C, 15N and 17O NMR, sydnones were showed the different chemical shifts which were caused by the effect of electron density on the different functional groups at 3,4- and 4- positions. From 15N NMR, the chemical shift of sydnones at N(2) and N(3) positions were discussed. 3(p-methylphenyl)sydnone with various solvents was also showed the different chemical shifts by using 15N and 17O NMR determination. 　　Second, A series of the single crystal of 3, 4-and 4-substitutions of sydnone was described by X-ray diffraction. The bond-lengths of sydnones were showed the different distances because of the subsitution groups of sydnone. The ability of election withdrawing substitution groups could be mesured from bond-strength of C(4)X bond. The effect of H-bonding of each bond length of sydnone ring was illustrated by the X-ray molecular structure. 　　Third, It is known that nitrile oxide is very useful as an precursor. For 3-arylsydonoe-4-carbonitrile oxide, it was not easy to synthesize because of the exceptional structure of sydnone ring. According to the reaction of NBS and 3-arylsydnone-4-carboxaldehyed oxime, the nitrile oxide was oxidized. Therefore, this compound first was determined by only IR spectrum. In this study, the novel method was found out by using 3-arylsydnone-4-carboxamide oximes reacting under the mixture of dilute acid and NaNO2 to give a high yield of very stable sydnone nitrile oxide. Thus, all spectra were first collected to confirm this sydonone nitrile oxide. 　　Finally, The reaction of nitrile oxides with the unsaturated C-C bond showed the mechanism of 1, 3-dipolar cycloaddition to form a 5-member hetrocyclic isoazoline. Base on the results of this study, the reaction could be considered a potential in organic synthesis. Therefore, this objective was concentrated on the reaction of sydnone nitrile oxide with various cycloalkenes to produce the 23 new compounds.