不对称

In a similar way, using N,N\'-dibenzyl tartamide as auxiliary,-(2-methyl)allyl-2-chloro-phenyl-methyl azide, a vital intermediate of Repaglinide, can be prepared via asymmetric allylation of o-chlorobenzaldehyde in

产物经氧化和碘加成内酯化反应得到阿伐他汀中间体(3R，5S)-3-羟基-5-碘甲基戊内酯(10)；将N-苄基酒石酸二酰胺用于邻氯苯甲醛的不对称烯丙基化反应以较高光学收率得-甲基烯丙基-2-氯苯基-甲基醇

Dimethyl dicarboxylate biphenyl and β-dimethyl dicarboxylate biphenyl have anti-hepatitis activity. The modification to them gave twelve asymmetry biphenyl compounds.

对保肝药物联苯双酯进行了修饰改造，得到12种不对称的联苯化合物，期望能够改变其药效及溶解性。

The first asymmetric total synthesis of coumarinolignoids Daphneticin and it's enantiomer was accomplished starting from 7-hydroxycoumarin and 3, 4, 5-trimethoxybenzaldehyde, in which Sharpless asymmetric dihydroxy reaction was used to construct chiral center, and Mitsunobu reaction was used to obtain desired configuration.

并以7-羟基香豆素和3，4，5-三甲氧基苯甲醛为起始原料，用Sharpless不对称双羟化反应构筑手性中心，用Mitsunobu偶联反应作为关键步骤，合成了手性的香豆素木脂素Daphneticin及其异构体。

We succeeded in synthesizing two different segments: C〓-C〓 and C〓-C〓, employing Sharpless dihydroxylation reaction, Julia coupling and samarium diiodide mediated reaction as the key steps.

我们从单保护的1，3-丙二醇出发，以Sharpless不对称双羟化反应，Julia偶联反应以及SmI〓参与的反应为关键步骤，经过艰苦的多条合成路线的尝试与探索，成功的得到了Phorboxazole A B的两个不同的边链部分C〓-C〓和C〓-C〓。

Studing on samarium diiodide promoted asymmetric intramolecular reducing coupling reactions, we have made the resolution of the racemic biaryl dials by using enantiomeric N-tert-butanesulfinamine as the resolving reagent successfully and thus obtained a series of axially chiral biaryl dials with high enantiomeric excess.

中文摘要在二碘化钐促进的分子内不对称还原偶联反应中，我们不仅对联芳基二醛底物的合成路线进行了优化，还发现N-叔丁基亚磺酰胺辅基可以作为手性试剂，成功地对联芳基骨架二醛化合物进行拆分，得到高对映体过量的轴手性二醛类化合物。

The academic circle of our country regards the dissymmetric information as the fundamental reason of counterfeiting, and this point of view is widespread.

对于假冒伪劣的综合成因，我国学术界将信息不对称视为根本原因的观点广为流传。

In order to adapt the rural electricity system which has the character load fluctuate frequentand the range of fluctuate is large, this paper apply instantaneous reactive power theory to detectreactive current of the system, this method enhance the speed of detection, at the same time, it canassure the detection precision when the load of rural electricity system is dissymmetric.

为了适应农电系统负荷波动频繁且波动范围大的特点，本文应用瞬时无功功率理论检测系统的无功电流，这种检测方法即提高了检测的速度，同时在农电系统负荷不对称的情况下也能保证检测精度。

The simulation results show that the die swell rate of height direction is greater than that of width direction. Due to the difference of material characteristic of the two polymers, the end section shape of coextrusion is dissymmetric drum. The coextrusion interface would be change during the extrusion swell process.

有限元模拟结果显示：聚合物在离开方形口模后，熔体高度方向的挤出胀大率明显大于宽度方向的胀大率，且两种熔体的挤出胀大率不同，熔体术端截面形状为不对称的鼓形；在挤出胀大段，共挤出界面的形状和位置会发生变化。

ANSYS is a finite element simulation software used to simulate the temperature field in selective laser sintering.By using the ANSYS parameter design language,the density of the thermal flow,the velocity and the path of scanning can be controlled.The effect of the scanning path on the temperature field in the SLS process is studied. Balling,which occurs at the end of the scanning line,is caused by the dissymmetric temperature field and the great temperature gradient.

利用有限元分析软件AN SY S，对激光烧结温度场进行了数值模拟，建立了激光烧结薄板的温度模型；运用APDL语言控制热源的热流密度、移动速度以及扫描轨迹；研究了激光行程对烧结温度场的影响，扫描端点温度场的不对称及较大的温度梯度造成了端点球化现象；激光扫描线间的耦合作用使端点球化现象随扫描线的增加而逐渐显著。

A series of dissymmetric Gemini surfactants with the structure ofC_(12H_(25)CH_(3_(2)N~CH_(2_(4)N~CH_(3_(2)C_mH_(2m+1),denoted as C_(12)-4-C_m(m is 14,16,18),have been synthesized with N,N-dimethylalkylamine and 1,4-dibromobutane as the initial reagents.

以N，N-二甲基脂肪胺和1，4-二溴丁烷为原料，合成了一系列具有不同疏水链的不对称Gemini表面活性剂C12H25(CH3)2N+(CH2)4N+(CH3)2CmH2m+1(C12-4-Cm，m=12，14，16，18)，并通过1H NMR、MS和元素分析等方法鉴定其结构。

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％。