物理化学学报 >> 1986, Vol. 2 >> Issue (06): 484-492.doi: 10.3866/PKU.WHXB19860602

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1,3-甲基-6-氮杂胸腺嘧啶和它与CH2=CH-Z(Z=CN, COCH)光环合加成产物晶体结构及光环合加成机理

王洪辉; 竺迺珏; 傅亨; 樊美公; 刘晓云   

  1. 中国科学院化学研究所; 中国科学院感光化学研究所
  • 收稿日期:1985-03-06 修回日期:1985-06-25 发布日期:1986-12-15

THE STRUCTURES OF 1,3-DIMETHYL-6-AZATHYMINE AND ITS PHOTOCYCLOADDUCTS OF CH2CH-Z(Z=CN, COCH3) AND PHOTOCYLOADDITION MECHANISM

Wang Honghui; Zhu Naijue; Fu Heng; Fan Meigong; Liu Xiaoyun   

  1. nstitute of Chemistry, Academia Sinica, Beijing; Institute of Photographic Chemistry, Beijing
  • Received:1985-03-06 Revised:1985-06-25 Published:1986-12-15

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摘要： 本文报导1,3一二甲基-6-6氮杂胸腺嘧啶和它与CH_2=CH—Z(Z=CH, COCH_3)光环合加成产物共5个晶体结构。结合EHMO计算结果, 确定光环合加成反应为三线态的双自由基机理, 自由基的稳定性决定区域选择性。自由基的旋转使反应没有立体选择性。利用晶体结构数据, 解释了>C=N一双键的高反应活性及加合物中NMR δH_8的差异的现象。

Abstract: The crystal structure of 1,3—dimethyl-6-azathymine and its four photocycloadducts of CH_2CH-Z(Z=CN, COCH_3) were determined by X-Ray diffraction. The main crystallographic data are listed in Tabie 1. The absolute configurations of the compounds(Ⅱ) and (Ⅳ) were not determined.
The molecular structure of 1,3-dimethy-6-azathymine is shown in Fig.1. Its six-membered ring is roughly planar. The C-N single bond lengths which are nearly equivalent in the six-membered ring are shorter than that in the photocycloadducts (see ...