中间体

The second synthetic strategy commenced from butane-1,4-diol 50, which underwent monobenzylation, Swern oxidation, enolization followed by acetylation and debenzylation to yield an intermediate 46 in an overall yield of 54% in a 4-step procedure.

第二条路线从1，4-丁二醇50开始，这个化合物经过单苄基化、Swern氧化、烯醇化随后乙酰化和脱苄基化共4步反应得到中间体46，总产率54％。

Then sodium ethoxide was used as base,the nucleophilic substitution of 2-pyrrolidone with the intermediate provided nefiracetam.

以碳酸钠为缚酸剂，摩尔比为1︰1的2，6-二甲基苯胺与氯乙酰氯反应合成了中间体2-氯-N-(2，6-二甲基苯基)乙酰胺；在强碱乙醇钠作用下，2-吡咯烷酮再与2-氯-N-(2，6-二甲基苯基)乙酰胺经亲核取代合成了目标化合物奈非西坦。

For the stepwise mechanism, the ethylene molecule was firstly adsorbed at the Brnsted acid site via π-hydrogen bonding to form a stable complex, which then went through the protonation, leading to the formation of the ethoxide intermediate. Furthermore, the ethoxide reacted with the second ethylene molecule to form the butoxide product.

对于分步反应机理，乙烯分子首先通过π-氢键作用在酸性位形成稳定的吸附络合物，再进一步发生质子化并生成乙醇盐中间体，随后乙醇盐与第二个乙烯分子发生碳－碳键结合形成丁醇盐产物。

The main products are as follows: Pharmaceutical Intermediate, Trimethyl Orthoformate , Triethyl Orthoformate, Sodium Methoxide, Power and solution Ethoxide,α-Chloropropionyl Chloride, Acetyl Chloride. Shandong Xinhua Junli Chemical Co.,Ltd.

公司主要产品为医药中间体，原甲酸三甲酯、原甲酸三乙酯、甲醇钠、乙醇钠、α-氯代丙酰氯、乙酰氯，其中原甲酸三甲酯、原甲酸三乙酯是国内唯一采用金属钠法工艺生产的企业。

Experiment results indicate that both the ethylenic derivative of benzophenone and the new synthesized polysiloxane are characteristic of three typical intensive and broad absorption bands in ultraviolet region at about 240nm, 288nm and 326nm, and show effective ultraviolet absorptive ability in wavelengths between 240nm and 400nm.

结果表明：中间体和聚硅氧烷在紫外光区均具有二苯甲酮衍生物特有的三条吸收谱带，对波长240~400nm的紫外光有良好的吸收作用。

In the presence of alkalinity and tetraethyl ammonium bromide, 2,4-dihydroxy benzophenone reacts with allyl glycidyl ether to form an ethylenic derivative of benzophenone, 2-hydroxy-4-(β-hydroxy-γ-allyloxy) propyloxy benzophenone, which can further undergo hydrosilylation with polyhydromethylsiloxane.

在相转移催化剂四乙基溴化按作用下，利用2，4-二羟基二苯甲酮与烯丙基缩水甘油醚在碱性水溶液中的开环加成反应，合成了中间体4-丙氧基－2-羟基二苯甲酮，将其进一步与聚甲基氢硅氧烷进行硅氢化加成反应。

The key intermediate 3-methylaminopiperidine was synthesized from 3-methylaminopyridine by two methods,formylation and lithium aluminium hydride reduction or condensation with triethyl orthoformate and sodium borohydride reduction,and then hydr...

以3-氨基吡啶为原料，分别通过甲酰化反应、氢化铝锂还原和原甲酸三乙酯缩合、硼氢化钠还原两种方法得到3-甲胺基吡啶，最后经催化氢化得到中间体3-甲胺基哌啶。

The key intermediate 3- methylaminopiperidine was synthesized from 3-methylaminopyridine by two methods, formylation and lithium aluminium hydride reduction or condensation with triethyl orthoformate and sodium borohydride reduction, and then hydrolysis.

以3-氨基吡啶为原料，分别通过甲酰化反应、氢化铝锂还原和原甲酸三乙酯缩合、硼氢化钠还原两种方法得到3-甲胺基吡啶，最后经催化氢化得到中间体3-甲胺基哌啶。

Glyoxylic acid is an important basic material or organic intermediate, widely used in the fields of perfume, medicine and pesticide, etc.

乙醛酸是一种重要的基本原料或有机中间体，广泛应用于香料、医药、农药等领域。

As an intermediate for preparing vanillin derived from glyoxylic acid, 3, 4-dihydroxymandelic acid is synthesized based on condensation of catechol and glyoxylic acid in alkaline aqueous solution.

以邻苯二酚和乙醛酸为原料，在碱性条件下发生缩合反应，合成了3， 4-二羟基扁桃酸，此物质是多种香料和药物合成的重要中间体。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。