取代

Thioureas have been attached great importance because of their special biological activities. A series of novel thiourea derivatives 4a~ 4e and thiosemicarbazide derivatives 5a~ 5e were synthesized by addition reaction of 2-phenyl-1,2,3-triazole-4-formyl isothiocyanate ( 1) with substituted 2-amino benzothiazole and 2-hydrazino benzothiazole respectively.

利用2-苯基-1,2,3-三唑-4-甲酰基异硫氰酸酯与2-氨基取代苯并噻唑和2-肼基取代苯并噻唑的加成反应合成了一系列二取代硫脲和氨基硫脲衍生物。

Is there a credible alternative to the nuclear deterrent?

是否有可以取代核威慑力量的可靠办法?

Twelve 20-hydroxyl ester analogues of camptothecin were prepared and evaluated in vitro antitumor activity.

为了改善取代喜树碱的溶解性、抗肿瘤活性和毒副作用,设计合成了十二个新的取代喜树碱20-位羟基酯衍生物.

Gradually factory workers have been displaced by machines.

工厂的工人已逐渐被机器取代。

These amine substituted acid may polymenze in an analogous manner to unsubst ituted oxo-anions.

这些氨取代酸可以与未取代的氧络阴离子相类似方式聚合.

The class consciousness replaced the religious family consciousness. The master consciousness replaced the dependence consciousness. The political participation took the place of political indifference.

阶级意识代替了宗法家庭意识，主人翁意识替代了依附意识，政治参与取代了政治冷漠，创新精神取代安贫知命，健康文明的生活方式取代了陈规陋习。

Optimism was gradually taking the place of pessimism.

乐观情绪逐渐取代了悲观主义。

The substitution of a purine for a pyrimidine, or vice versa is a transversion.

嘌呤为嘧啶取代或嘧啶为嘌呤所取代,叫做颠换.

He builds furniture using wooden pegs instead of nails.

他用木楔子取代钉子制作家具。

New laws will soon replace existing legislation.

新法律即将取代现行法规。

Around 1910 motorized carriages were beginning to replace horse-drawn cabs.

大约从1910年起，机动车开始取代马车。

One fireboat will replace the existing Fireboat No.3 and the other the Fireboat Alexander Grantham.

其中一艘灭火轮将取代现时的三号灭火轮,另一艘则取代葛量洪号灭火轮.

This paper reports the synthesis of nine N-( 4-carbethoxy-4-substituted butyryl)-N-substituted glycines and their corresponding t-butyl esters. The former were expected to have inhibitory activity of angiotensin-converting enzyme. All of the compounds mentioned above were unreported in the literature.

本文报道9个估计具有血管紧张素转化酶抑制活性的N-（4-乙氧羰基-4-取代丁酰基）-N-取代甘氨酸及其相应叔丁酯的合成和鉴定。

In this paper is reported for the first time a new nucleophilic substitution reaction; substituting a secondary nitramino group on the aromatic ring with an azido group.

本文首次报告了叠氮基取代芳环上仲硝胺基的新亲核取代反应。

The activities of palladium catalysed cross coupling reactions of substituted bromobenzenes were studied.

分析了温度、化剂、同取代基团对取代溴苯发生钯催化偶联反应活性的影响.

By the 1930s the wristwatch had almost completely supplanted the pocket watch.

到了20世纪30年代，手表几乎完全取代了怀表。

The stuffy "50s gave way to the swinging "60s.

古板乏味的50年代被多姿多彩的60年代所取代。

Tour buses have replaced railway cars.

观光巴士已经取代了火车。

Then the telegram was replaced by the telex machine, which was followed by the facsimile.

后来电报被电传机取代, 后者又被传真机所取代.

Nucleophilic Aromatic Substitution . Strategies in the Synthesis of Multisubstituted Benzene Derivatives.

亲核性芳香取代. 多取代苯衍生物合成的策略.

Conclusions: The alkanes substituted phenolshigher antioxidant activity than that of electron-withdrawing groups substituted phenols.

结论: 烷烃基类取代物易于抗氧化,卤代烃基或硝基类取代物抗氧化活性差.

Use poly8.5unsaturated spread instead of butter.

用多不饱和抹酱取代黄油。

The fluorescence intensity of porphyrin also relates to the substituent positions on the phenyl groups.

此外,荧光强度还与卟啉的苯环上取代基的取代位置有关.

The theory has been superseded by more recent research.

这一理论已为新近的研究所取代。

Their indecision has been replaced by confidence and steely determination.

他们的优柔寡断已经被自信和钢铁般的决心所取代。

Directing Effects in Aromatic Substitution . Nucleophilic Aromatic Substitution . Strategies in the Synthesis of Multisubstituted Benzene Derivatives.

亲电芳香取代反应的定位效应. 亲核芳香取代反应. 合成多取代苯衍生物的策略.

Did she usurp his place in his mother's heart?

她取代了他在他母亲心目中的地位吗？

The new design will eventually replace all existing models.

新的设计最终将会取代所有现有的型号。

The chloromethylation reaction consists of electrophilic substitution reaction and nucleophilic substitution reaction, the nucleophilic substitution is the rate-controlling step and the hydroxymethyl cation (+ CH20H) is the really effective electrophile.

氯甲基化反应由亲电取代反应和亲核取代反应组成，亲核取代反应是反应的速率控制步骤，羟甲基碳正离子（+CH2OH）；是真正有效的亲电试剂。

Designer beers and trendy wines have replaced the good old British pint.

时尚的啤酒和流行的葡萄酒已经取代了老牌的英国啤酒。