呋喃[3,2-b]吲哚类化合物碱性条件下扩环重排反应

吲哚类化合物的重排扩环反应通常是在酸性条件下完成.研究发展了一种吲哚类化合物在碱性条件下的扩环重排反应.通过在1 ∶ 1(体积比)的乙二醇和水的混合溶剂中回流呋喃[3,2-b]吲哚类化合物和氢氧化钾的混合物可以将呋喃[3,2-b]吲哚类化合物高产率地转化成喹啉酮类化合物.     

氢氰酸与水的异构化反应密度泛函理论研究

采用电子结构理论中的B3LYP密度泛函方法(DFT),在B3LYP/6-311 G(3df,2pd)水平上,在气相和水相中分别研究了异氰酸与水通过分子间氢键首尾相连,形成五元环过渡态,再转换成氢氰酸的异构化反应.计算结果表明,在水相中异构化过程的活化能比在气相中低,无论在气相还是在水相中异氢氰酸通过水氢键转化成氢氰酸容易些,而氢氰酸由水氢键转化成异氢氰酸相对要困难些,分子间氢键和溶剂化效应在异构化反应过程中起到重要的作用.     

企业资产重组中的若干问题

我国企业的主体是国有企业，通过对锦州万得工业集团资产重组历程的分析，指出企业在资产重组过程中出现的常见问题，并提出了解决办法。     

环烯并[b]吡咯衍生物的质谱研究

环烯并吡咯衍生物在ＥＩ和ＦＡＢ条件下,可以发生游离基引发的氢重排失去一个中性的烯酮型分子,生成３－羟基－２－甲酰乙酯环烯并吡咯,后者由于邻位效应,又失去一分子乙醇、ＣＯ及发生缩环和一系列吡咯环的裂解反应。一些环己烯并吡咯衍生物的离子可以发生ＲＤＡ反应。     

HCN对合成氨生产的影响

本文较系统地提出了HCN在合成氨生产中的生成、危害、脱除方法及分析方法。     

Variation induced by DNA rearrangement in a transgenicBt+CpTI cotton strain

In the development of transgenicBt + CpTI cotton cultivars, one male and female sterile mutant has been found in a homozygous T₄ strain in our laboratory. The mutant plant, as well as its leaves, buds and flowers, is only 1/2–1/3 as large as that of the wild transgenicBt + CpTI bivalant cotton plants. Cytological observation found that the chromosome number of the mutant is 2n = 52; however, there are 4–8 univalents observed in meiosis I of pollen mother cells. Laboratory bioassay indicated that the mutant was highly resistant to bollworm as the wild plants. PCR amplification revealed thatBt andCpTI genes in the mutant were still intactly inserted. However, small deletion of flanked area had been observed in the mutant by Southern blotting analysis. So it is proposed that the mutant phenotype might result from either the DNA deletion or T-DNA transferring in plant genome. No such report has been presented that the rearrangement of chromosome structure in a homozygous transgenic line occurred. Further analysis is ongoing.     

硝酸铵催化的2,10-环氧蒎烷液相重排反应规律研究

研究了硝酸铵催化剂体系和溶剂对2,10-环氧蒎烷液相重排反应的影响．重点考察了催化剂分散状态、溶剂性质及溶剂用量对重排产物分布的影响．实验结果表明：用硅胶吸附的硝酸铵具有较好的活性,强极性的硝基甲烷溶剂中对于紫苏醇的选择性最好,而弱极性的氯仿和1,1,1-三氯乙烷则有利于桃金娘烯醇的生成．     

合成芳香异氰酸酯的一种新方法

在固－液相转移催化下，采用Curtius重排反应合成了一系列芳香异氰酸酯。该法具有反应条件温和，操作简便，产率高等优点。     

狄里克莱级数的精确级

研究了狄里克莱级数引入精确级后系数经过重排的增长性,得到了有限级狄里克莱级数的系数经过重排后级和型保持不变的充要条件。     

An Improved Genetic Algorithm for Problem of Genome Rearrangement

In view of the fact that the problem of sorting unsigned permutation by reversal is NP-hard, while the problem of sorting signed permutation by reversal can be solved easily, in this paper, we first transform an unsigned permutation of length n,π （π1 ,… ,πn）, into a set S（π） containing 2^n signed permutations, so that the reversal distance of π is equal to the reversal distance of the optimal signed permutation in S（π）. Then analyze the structural features of S（π） by creating a directed graph and induce a new computing model of this question. Finally, an improved genetic algorithm for solving the new model is proposed. Experimental results show that the proposed model and algorithm is very efficient in practice.