查询词典 alder

After prolonged heating 15h, 120° of the origina lly isolated stereoisomer B (melting C point mp: 157° Diels and Alder obtained two new stereoisomers E (mp: 153° and F C), C (mp: 163° Equilibration of B with a catalytic amount of a strong base at 25° ga ve a C).

在比原始分离异构体 B (熔点： 157°C)的方法延长加热时间之后(15h， 120°C)， Diels and Alder 获得了两个新的异构体 E(熔点：153°C)和 F(熔点：163°C)。

1 Piece OLD Solid Alder, Carved top!!!! Cherry Sunburst with Natural wood linings.

一整块Alder老木，樱桃渐变色，可以看到自然木纹。

So, by the Diels-Alder reaction of tetraphenylcyclopentadienone, acenaphthenecyclone and benzophenanthrenecyclone with the vinyl groups in C gum, three kinds of polymethylvinylsilicone oil with condensed aromatics are synthesized respectively: polymethylvinylsilicone oil with tetraphenylphenyl groups (called C_1 gum for short), polymethylvinylsilicone oil with acenaphthenyl groups (C_2 gum) and polymethylvinylsilicone oil with benzophenanthrene groups (C3 gum).

根据此原则，利用四苯基环戊二烯酮、苊式环戊二烯酮和菲式环戊二烯酮与C胶上的乙烯基进行Diels—Alder反应，分别合成了三种含稠环基团的乙烯基硅油：四苯基苯基乙烯基硅油(C_1胶)，苊式多苯基苯基乙烯基硅油(C_2胶)和菲式多苯基苯基乙烯基硅油(C_3胶)，并根据~1HNMR谱图上不同氢原子的积分面积计算了三种胶中稠环基团和乙烯基的含量。

Vanillin 58 was used as starting material, which underwent methylation, bromination, acetalization, lithiation followed by nucleophlic addition to aldehyde, Diels-Alder reaction, selective reduction and lactonization to produce diphyllin in an overall yield of 38%(7 steps).

这个方法从香兰素58开始，经过甲基化、溴化、成乙二醇缩醛反应、锂化而后对醛亲核加成、Diels-Alder反应、选择性还原反应和内酯化反应共7步，最后得到diphyllin，总产率38％。

Quinone methides, generated in situ from the reaction of 4-hydroxycoumarin with benzaldehyde, formaldehyde and pentanal, underwent the Diels-Alder reaction with silyl enol ethers to give a series of 3,4-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran derivatives in high yields.

通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应，以较高产率合成了一系列含有硅氧基的3，4-二氢-2H，5H-吡喃并[3，2-c][1]苯并吡喃-5-酮衍生物。

Accordingly, in the original reaction (formation of B from cyclopentadiene and benzoquinone) Diels and Alder found only one of the following six conceivable stereoisomers of B.

因此，在该原始反应中(即通过P-苯醌和过量的环戊二烯生成B)，Diels and Alder发现在他们推测的六个立体异构中，只有一个出现。

Methyl Sartortuoate and Methyl isosartortuoate are two tetracyclic tetraterpenoids isolated from the sarcophyton tortuosum tixier-durivalt by Chinese scientists. Biogenetically, it could be regarded as a Diels-Alder combination of two cembrenoids, i.

扭曲肉芝甲酯和异扭曲肉芝甲酯是中国科学家从南中国海扭曲肉芝软珊瑚中分离到的一种四环四萜化合物，从生源角度考虑，可能由两个西松烷型二萜化合物经Diels-Alder反应组装而成。

The latest applications of boronic acids as catalyst to organic synthesis are reviewed, focusing on the catalytic activities and reaction mechanism of different catalysts discovered in condensation reaction, carboxylic acid reduction reaction, and Diels-Alder reaction.

吴记勇 ；方浩*；徐文方摘要：综述了有机硼酸类作为催化剂应用于有机合成反应中的最新研究进展，重点介绍了所发现的各种有机硼酸催化剂在缩合反应、羧酸还原反应、Diels-Alder反应中的催化活性以及反应机理。

Cyclopentadiene monomer is not stable and undergoes spontaneous Diels-Alder addition to produce the dimer and higher polymers.

环茂二烯单体是不稳定的，它会自发进行Diels-Alder加成反应，产生二聚体和更高的多聚体。

In addition to cyclopropanation, the typical Diels-Alder reaction between cyclopentadiene and N-acryloyl-l,3-oxazolidinine-2-one with Ll-L8/metal complexes have also been studied.

对于新配体在Diels-Alder反应中的对映选择性的研究，我们采用环戊二烯与3-丙烯酰基-2-噁唑啉酮的反应。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷