查询词典 membered

The Nazarov cyclization, a powerful tool for the construction of five-membered carbocycles from divinyl ketones and related compounds, has attracted increasing attention in recent years due to its wide applications in the synthesis of complex natural and unnatural products.

Nazarov环合反应是通过二烯酮类物质和类似化合物构建五元碳环的有效方法。由于该方法广泛地应用于复杂天然和非天然产物的合成，近年来引起人们的广泛关注。

The first part reports some new reactions of BNAH, especially the reductive cyclizations of some activated ethylenic compounds to five-membered carbocycles and a sevenmembered enolic ether ring, both of which may be useful in related areas.

详细论文的研究对象是重要的辅酶NADH的化学模型1-苄基-1，4-二氢烟酰胺。论文包括一个对近期该领域进展的综述和三部分工作。

The synthesis of DPEP and ETIOP were investigated, and our studies was focused on the porphyrins with five-membered exocyclic rings.

石油卟啉DPEP和ETIOP的全合成：合成石油卟啉可以为天然石油卟啉的结构鉴定提供标准样品。

The sodium ions located in the 12-membered ring main channel (with Q〓〓0.2 MHz) of zeolite omega are fully hydrated and so mobile to average out the 〓H-〓Na dipolar interaction, while those in the gmelinite cage (Q〓=2.3 MHz) are less hydrated and closely bonded to the lattice oxygen.

3〓Na MAS及〓Na二维四极章动实验的研究表明，在NaΩ分子筛中存在两类不同水合状态的钠离子：一类处于12-圆环主孔道中(四极作用常数Qcc＝0.2MHz)，另一类处于菱钾沸石笼里(Qcc＝2.3MHz)。

But the six-membered α-hydroxylactone of CPTs can hydrolyzed to its inactive carboxylate form readily at physiological pH.

但是，喜树碱的六元α—羟基内酯环在体内易水解，且存在毒性较大、具有种属差异等不足。

Toxicity and species difference are the other problems of CPTs. Homocamptothecins , a novel CPT analog which contain an expanded seven-membered β-hydroxylactone, have shown elevated antitumor activity and improved stability without species difference.

高喜树碱是近年来刚刚出现的一类CPT类似物，其特征是将α—羟基内酯环改造成七元的β—羟基内酯环，不仅活性明显提升，而且体内代谢稳定性也大大提高，并且不存在种属差异现象。

It is worthwhile to note that only the α-amino acids, could be activated into the five-membered cyclic imino acetoxyphosphoranes, while the β-ones not.

实验表明，仅α-氨基酸能发生这种自组装成肽反应，而β-氨基酸却不能进行，这是由磷的五元环特性决定的。

A series of five-membered lactams containing 1, 3-diene moity were prepared by RCEM reaction, the scope of this reacrion was expanded.

在上述研究的基础上，我们利用烯炔关环复分解反应合成了一系列含 1， 3-二烯结构单元的五元内酰胺化合物，从而进一步拓展了关环复分解反应的应用范围。

The absorption maxima and emission maxima didnt change obviously between the five-membered compounds when N-methyl as the bridge atom. The value of extinction coefficient was increased obviusly compared naphthalimide with naphthalic anhydride.

甲基化氮为桥原子的五元化合物之间最大吸收和发射波长相差不大，萘酰亚胺的消光系数比萘酐增加明显，loge最大相差可达0.45，荧光强度也略有增加，相差0.1左右。

Avermectin are 16-membered pentacyclic lactone compounds produced by Strephomyces avermitilis, which have extensive and high effect on many kinds of insect and mite.

阿维菌素是从阿维链霉菌的发酵产物中分离出来的16元大环内酯类抗生素，对多种动物寄生虫及农业害虫害螨有很高的杀虫活性，但是该药剂光照易降解而持效期短。

If you are unfortunate enough to the lovelorn, please tell me, I will help you out, really, please contact me!

如果你不幸失恋了，请告诉我，我会帮助你摆脱困境，真的，请联系我啦！

China's plan to cut energy intensity by 20 percent and pollutant discharges by 10 percent between 2006 and 2010 is a case in point.

中国计划在2006年到2010间降低20%的能源强度和减少10%的主要污染物排放，就是一个这样的例子。