介绍了对化学取代基 (R 基团 )进行相似性比较的工作 .每个R 基团主要依赖一些对反应影响较为明显 ,同时又便于计算的结构描述符来进行描述 ,例如电负性、氢键受体、氢键给体等参数 .由于与反应核心相距过远的环境对反应的影响较小 ,R 基团相似性比较对象 ,就由每个R 基团截取从它与母体连接的位点出发向外扩展 6层的子结构组成 .在确立了对R 基团描述和距离限制的基础上 ,提出了用一个 45维向量表示一个R 基团 ,并由化学结构的比较 ,转化为向量比较来实现R 基团相似性比较的方法 .采用这一方法 ,成功地对大量的R 基团进行了相似性的区分 ,并实现了对未知化合物进行相似性预测的目标 The work on the similarity comparison of chemical substituents (R groups) is introduced.Each R group mainly relies on some structure descriptors that have obvious effect on the reaction and are easy to calculate at the same time, such as electronegativity, hydrogen Bond acceptors, hydrogen bond donors and other parameters.Because the environment far from the reaction core has little effect on the reaction, the similarity of R group is compared with that of each R group from the position where it is connected to the parent Point out to expand the structure of the sub-structure of 6. Based on the description of the R group and the distance limit established, we propose to use a 45-dimensional vector to represent a R group, and the chemical structure of the comparison, into a vector Comparison of R groups to compare the similarity method.Using this method, a large number of R groups were successfully carried out the similarity of the distinction, and to achieve the unknown compound for the prediction of the similarity of the target