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Reaction of 5'-O-p-methoxytrityl-thymidine with 1, 1'-carbonyl-diimidazole gave the 3'-O-carbonylimidazolide, which was condensed in high yield with 3'-O-protected thymidine to give a dithymidine carbonate. In the same way, we obtained the protected trithymidine dicarbonate. After deprotection, we obtained quantatively the trithymidine dicarbonate.By the same stratagy, we completed the synthesis of dithymidine sulfite.It was shown that allyl can be used as a good protection group for hydroxyl of ribose in the synthesis of oligonucleotides consisting in some unstable nucleotide analogues.

我们在第一部分工作的基础上,以烯丙基作为3'-OH的保护基合成了保护的三胸苷碳酸酯以及二胸苷亚硫酸酯,用我们所得的脱保护条件进行了脱保护研究,得到了三胸苷碳酸酯以及二胸苷亚硫酸酯,并研究了它们合成中的一些化学问题,结果表明:烯丙基能很好地运用于这两类寡核苷酸类似物的合成中,其脱保护条件为中性,不会影响碳酸酯键及亚硫酸酯键。

Both catalytic activity and selectivity of Ru(PPh_3)_3Cl_2 were improved in ionic liquid BMImPF_6/DME medium.The conversion of hexene and selectivity ofβ-adduct for the hydrosilylation reaction of 1-hexene with triethoxysilane catalyzed by Ru(PPh_3)_3Cl_2 in ionic liquid BMImPF_6DME (V/V=1/4) medium at 90℃were 100% and 89.0%,respectively.

实验结果表明,在乙二醇二甲醚/离子液体1-丁基-3-甲基咪唑六氟磷酸盐(BMImBF_6)(V/V =1/4)介质中,于90℃下,己烯与三乙氧基硅烷反应的转化率为100%,β加成物的选择性可达89.0%,而用Rh(PPh_3)_3Cl作为反应的催化剂,在纯离子液体BMImPF_6中,就可以高效催化烯烃与三乙氧基氢硅烷的加成反应,过渡金属Rh(PPh_3)_3Cl,Ru(PPh_3)_3Cl_2催化剂/离子液体BMImPF_6催化体系,不仅解决了产物与催化剂分离困难这一难题,同时,离子液体BMImPF_6的存在提高了过渡金属Rh(PPh_3)_3Cl,Ru(PPh_3)_3Cl_2催化硅氢加成反应的活性,特别是β加成物的选择性。

Alkylphenol ethoxylates are nonionic surfactants and extensively used in industry. Manufacturers in Taiwan used to import nonene to produce nonylphenol and nonylphenol ethoxylates. They used to import octylphenol directly because it isn't easy to get octenes.

烷基酚聚乙基醚醇是工业上用途非常广泛的非离子性界面活性剂,国内目前有进口壬烯生产壬基酚及壬基酚聚乙基醚醇,而由於受限於辛烯原料取得不易,辛基酚都是直接进口。

As a useful fluorinated product,hexafluoropropene trimers can be prepared from hexafluoropropene oligomerization by gas phase-and liquid phase-methods,and many fluorocarbon surfactants such as full-fluoride nonene oxygen benzene sodium can be derived from perfluorinated nonene.

六氟丙烯可通过气相和液相法进行聚合制得六氟丙烯三聚物,即全氟壬烯,全氟壬烯可以进一步衍生出如全氟壬烯氧基苯磺酸钠等多种氟碳表面活性剂,是一种比较有用的含氟产品。

It is found that the stereochemistry of the reactions of telluronium allylide,crotonylide and trimethylsilyallylide with α,β-unsaturated esters and amides can be tuned by thechoice of reaction conditions.

利用反应条件的变化首次实现了烯丙基、巴豆基、含硅烯丙基碲叶立德与α,β-不饱和酯、酰胺进行环丙烷反应的立体化学调控,能高立体选择性地、高效率地合成两种不同几何异构体中的一个。

A one-step method for the synthesis of aromatic indolizine derivatives byintramolecular 1,5-dipolar cyclization reaction of 2-(2-arylethenyl)pyridinium N-ylidesin the presence of an oxidant has been studied for the first time. In the presence ofelectron-deficient olefins, however, 2-(2-phenylethenyl)pyridinium N-ylides underwent1,3-dipolar cycloadditions and then aromatized in situ by TPCD to produce indolizinederivatives, indicating 1,3-dipolar cycloaddition proceed more readily than 1 ,5-dipolarcyclization in these conditions. Pyridinium disubstituted N-ylides, readily obtainedfrom corresponding pridinium and β-chlorovinyl ketone, underwent thermalintramolecular 1,5-dipolar cyclization to give indolizine derivatives easily.Indolizinecarbaldehyde derivatives were synthesized starting from 2-pyridinecarbaldehyde in four-steps involving 1,3-dipolar cycloaddition reaction.

本文首次研究了2-(2-芳基乙烯基)吡啶N-叶立德在氧化剂存在下的分子内1,5-偶极环化反应,采用一锅法合成了中氮茚衍生物;研究了这些N-叶立德的1,5-偶极环化和1,3-偶极环加成反应的选择性,发现当有缺电子烯烃存在时,优先进行1,3-偶极环加成反应,而不再发生分子内1,5-偶极环化反应;由β-氯乙烯酮方便地得到了烯丙基N-叶立德,他们在加热时进行分子内1,5-偶极环化反应而得到中氮茚衍生物;由2-吡啶甲醛为起始原料,通过1,3-偶极环加成反应等四步反应,得到了重要的中氮茚甲醛衍生物,这些反应都具有条件温和和操作简便的特点,是合成中氮茚衍生物的新方法。

A novel polymeric organic thermal stabilizer for PVC was designed and synthesized by acryloylthiourea grafting on polystyrene which was nitrified by HNO3 and then reducted by Sn powder to amine.

以经部分硝化和还原的低分子量聚苯乙烯为母链,利用其胺基和丙烯酰基异硫氰酸酯加成,合成了一种新型有机高分子型PVC 热稳定剂——丙烯酰基硫脲接枝聚苯乙烯,其结构经IR和元素分析表征。

The algicidal performances of monomer dimethyldiallylammonium chloride and a commercial algicide dodecyldimethylbenzylammonium chloride( 1227 ) were contrasted with that of PDM.

对两种营养化的模拟水体,通过灭藻实验,研究了聚二甲基二烯丙基氯化铵系列样品的静态灭藻性能,考察了加药量、作用时间、特征黏度等因素对灭藻性能的影响规律,并与聚合物单体二甲基二烯丙基氯化铵及市售灭藻剂十二烷基二甲基苄基氯化铵(1227)的灭藻性能进行了对比。

A new monomer,4-hexanoxyl-4′-undecylene-[10]-acyloxyazobenzene was synthesized using the main materials:phenol,underlenic acid,1-bromo- n -hexane, p -nitrophenol,thionyl chloride,by the substitution,reduction,couping and diazotization methods.A new polymer was prepared by hydrosilation reaction of poly (methylhy-drosiloxane) with the monomer.

以苯酚、十一烯酸、正溴己烷、对硝基苯酚和二氯亚砜为主要原料,通过取代、还原、重氮化和偶合等反应,合成了一种新的液晶单体 4-己氧基-4′-十一烯-[10]-酰氧基偶氮苯,并与聚通过硅氢加成生成一种新的高分子液晶。

The results indicated the ally1 carbon of cyclohexene was catalytically oxidized by molecular oxygen at atmospheric pressure in the presence of the polymer complex and a trace of HOAc at 70℃, which afforded corresponding alcohol, ketone and hydroperoxide acting as intermediate.

结果表明,70℃时,以微量醋酸为添加剂,在催化剂的催化作用下,以常压氧气氧化环己烯,得到烯丙基位的氧化产物环己烯醇、环己烯酮和中间产物环己烯过氧化氢。

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推荐网络例句

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里,举止就文雅一些,因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计,这件高贵的制服是香港本土制造,是我们第一套不配帽子的制服。

Do not 'inflate' your achievements and/or qualifications or skills .

不要 '夸大' 你的业绩或成果,条件或者技能。