查询词典 tris nitro-methane

The first synthetic route uses 1,2,4-trimethoxybenzene and chloroacetonitrile in forming 2,4,5-trimethoxy-a-chlor-acetophenone under the anhydrous condition, then the intermediate condensates with papaverine forming the core pyrro[2,l-a]isoquinoline, followed by formation and lactonization to form the lactone ring. The second synthetic route uses prepared aldehyde with prepared ethyl nitroacetate by Knoevenagel condensation to obtain 2-Nitro-3-(2,4,5-tris-methoxy-phenyl)-acrylic acid ethyl ester and 2-Nitro-3-(2,4,5-tris-benzyloxy -phenyl)-acrylic acid ethyl ester etal intermediates. The lamellarin skeleton could arise from condensation of the papaverine and these intermediates by Michael reaction, the ester group is provided for subsequent lactonization. The third synthetic route uses coumarin or indan-l,3-dione derivatives and papaverine to form lamellarin under basic conditions.

第一条路线首先从1，2，4-三甲氧基苯出发与卤乙腈作用合成卤代芳酮中间体，然后与罂粟碱反应合成开链片螺素，最后经乙酰化、去保护、成内酯环得到片螺素；第二条路线由制备的芳醛和制备的硝基乙酸乙酯经缩合得到2-硝基-3-芳基丙烯酸乙酯，然后由该中间体与罂粟碱反应，在完成关环的同时也引入酯基，最后去保护、成内酯环得到片螺素；第三条路线是由香豆素或茚二酮出发，经溴代后的中间体与罂粟碱反应，得到片螺素的基本框架。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。