查询词典 pentacyclic

Avermectin, produced by Streptomyces avermitilis, is a group of pentacyclic lactone antibiotics which have been widely used as antiparasitic drugs in veterinary and agricultural fields.

阿维菌素是由阿维链霉菌产生的一种具有杀虫活性的大环内酯类抗生素，在农业和畜牧业中应用广泛。

Belgium imports of selected fabrics and Japan 75 # high-carbon stainless steel, pentacyclic spring as a strong core, can provide more load bearing capacity.

选用比利时进口面料及日本75#高碳精钢，五环弹簧作为坚强核心，能提供更强承托力。

In some cases, its epimer 4 was also obtained. 22 compounds were synthesized, among them 18 were new.3. Using the intramolecular Pictet-Spengler reaction to form the pentacyclic skeleton of Et-743, the byproducts 25 were obtained under various conditions. The structures of them were determined to be 1, 2-dihydro-isoquinoline compounds, and the mechanism of the reaction was proposed.B. The synthesis of the analogs of Et-743Because of the failure of removing the protective groups in compounds 14, the synthetic strategy was adjusted.

对于苄基保护的羟基化合物13a，顺利得到化合物30，然后与不同的羧酸反应得到18个酯化合物33-50；对于苄氧羰基保护的氨基化合物13b，由于脱除保护基的化合物31在空气中不稳定，所以我们采取不经分离纯化，直接与羧酸反应得到酰胺化合物53-62，然后再分别对其C-21位的羰基进行还原氰基化，得到10个酰胺目标化合物63-72，另外，我们还对羟基转化为氨基的反应进行了探索。3。

We will be together with the people of the world and unceasing practical action, so that the Olympic flame burning forever, forever pentacyclic flag standing firm and let the Olympic spirit immortal Inverness

我们将会和世界人民一起用永不停息的实际行动，使奥林匹克之火永远燃烧，让五环旗永远屹立不倒，让奥林匹克精神永世不朽

Based on theoretical calculation of electronegativity of groups offlotation-reagent and method of infra-red adsorption spectroscopy, the collection andadsorption of α-nitroso-β-naphthol in hematite flotation have been studied. The chemicaladsorption seems to be predominant owing to formation of pentacyclic nitrosyl chelate com-pound by atoms of nitrosyl bond in α-nitroso-β-naphthol together with Fe~(3+) on hematitesurface.

研究了α-亚硝基β-萘酚对赤铁矿的捕收性能及吸附规律，导出了吸附方程和吸附速率方程用药剂基团电负性理论计算以及红外吸收光谱法论述了其作用机理α-亚硝基β—萘酚主要是以N O键合原子与赤铁矿表面的Fe形成N O五元环螯合物而化学吸附。

The synthesis of the pentacyclic skeleton of Et-743 and the construction of the five chiral centers thereof.1. The core pentacyclic skeleton of phthalascidin was constructed with L-dopa as the starting material via thirteen steps. First, two basic synthons, the C-1 functionalized tetrahydroisoquinoline compounds 8 and N-protected Z-dopa derivative 9, were prepared from L-dopa. They were coupled via amide bond to form the dipeptide compounds 10, which were the first key intermediates. Then the primary hydroxyl groups were transformed into the corresponding amino aldehydes 11 via Swern oxidation. Followed by the intramolecular Pictet-Spengler cyclization, the pentacyclic compounds 12 were synthesized.

五环骨架的构建及五个正确手性中心的确立：1.1我们以L-多巴为起始原料，经过多步官能团保护和转化合成了基本结构单元8然后和苯丙氨酸衍生物9，通过缩合反应生成酰胺中间体10，经Swern氧化得到醛化合物11，然后再次利用分子内改良的Pictet-Spengler反应一步构建c，d两环，得到五环骨架化合物12，最后，实现了21-位羰基向氰基的转化，得到了C-1位官能化的化合物14，化合物14不但具有和Et-743一致的五环骨架，而且分子中五个手性中心立体构型也与其完全相同：其中，3，位和13，位的手性中心由原料L-多巴带入，而1，位，11，位和21，位手性中心则通过不对称诱导而确立。

Pentacyclic spandex office, a person in charge told reporters.

五环氨纶办公室一位负责人告诉记者。

Betulinic acid, a pentacyclic triterpene, has recently been reported to possess antitumor activity against cultured human melanoma cells.

1995年，人们首次发现了白桦酯酸的抗黑色素瘤活性以及作用的选择性，被称为是很有前景的抗肿瘤候选药物。

Results showed that during the carbonization of furfuralcohol resin C-O bond rupture of pentacyclic ring, took place firstly, bringine C-H bond rupture.

结果表明：糠醇树脂炭化裂解过程首先是五员杂环内的碳氧键发生断裂，引起碳氢键断裂。

ATA was found to exhibit more distinctive cytotoxicity toward human cervical squamous carcinoma HeLa cells than oleanolic acid, which suggested that the position of the carboxyl group significantly affects the cytotoxicity of oleanane-type pentacyclic triterpenes with a carboxyl group.

周晓华被发现展品更为鲜明的细胞毒性，对人体颈部鳞癌Hela细胞比齐墩果酸，这表明的立场与羧基显着影响细胞毒性的齐墩果烷型pentacyclic三萜类化合物与羧基。

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。