三尖的

Cephalotaxine ester of 2-oxo-6-methylheptanoic acid was treated with lithium diisopropylamide and Me O-(1-methoxyisopropyl)glycolate to give a mixture of homoisoharringtonine and its stereoisomers with 56% yield. The four stereoisomers separated by TLC showed identical mass spectra and almost superimposed IR but with different 1H NMR spectra. The configuration of the 2'-C and 3'-C of the four isomers were postulated based upon their 1H NMR spectra as compared with the 1H NMR spectra of isoharringtonine and its stereoisomers.

2-氧代-6-甲基庚酰基三尖杉碱(3)与0-(1-甲氧基异丙基)羟基乙酸甲酯(4)在强碱性试剂二异丙胺锂存在下，起亲核加成反应，反应中间体5在室温用酸性丙酮水解，得到一种新的三尖杉酯类生物碱一一高异三尖杉酯碱(6c)及其立体异构体(6a、6b、6d)的混合物，产率56%、通过制备薄层层析分得这四个立体异构体，它们的1H NMR和异三尖杉酯碱及其立体异构体的1H NMR类似，推定了它们的绝对构型。

Starting from piperonal, the initial total synthesis of CET involved BischlerNapieralski reaction, 3, 2-sigmatropic rearrangement, unusual Nazarov-type electrocyclization, and autoxidative dehydrogenation of desmethylcephalotaxine to desmethylcephalotaxinone etc.

第一条路线我们以胡椒醛为起始原料，经Bischler-Napieralski反应，[3，2]-σ重排，6-6环系到7-5环系的还原重排，Nazarov氧化环化；碱性条件下脱甲基三尖杉碱到脱甲基三尖杉酮碱的氧化脱氢等20步反应，完成了三尖杉碱的全合成。

Furthermore, a biogenesis-based synthesis of CET was developed, which realized the plausible biogenetic transformation by a transannular reductive skeletal rearrangement of cyclic amino enone 45 to key ring skeleton of CET under mild condition directly.

化合物17经Wacker氧化、环化得到重排前体不饱和酮45，45在温和的还原条件下重排得到三尖杉碱五环骨架化合物34，从而实现了三尖杉碱的全合成。第二条路线较前一条步骤更短，合成更方便，收率更高（从二酯化合物8计合成三尖杉碱的总收率可达10％）。

Three patients died 109, 180, and 659 days after surgery, respectively, the first patient after tricuspid valve replacement and the latter 2 after tricuspid valvuloplasty.

术后分别有三个病人在109天、180天和659天死亡，他们是第一例行三尖瓣置换术和最后两个行三尖瓣成形术的患者。

ABSTRACT This thesis is aimming at the synthetic study of Cephalotaxine, and consists of the following three parts: Charpter 1 reviews the isolation, chemical structure identification, biological activities, and synthetic studies of structurally unique antileukemia Cephalotaxus alkaloids.

本论文以三尖杉碱的全合成新方法为研究的核心，共分以下三部分内容：第一章简要地概述了天然三尖杉生物碱的分离、结构及生理活性，三尖杉碱的全合成研究。

Considering the slow growth rate of Cephalotaxus furtunei, field trials were conducted including seedling fostering, plantation cultivation as well as harvesting mode to establish systematic technique including nursing of super seedlings, cultivation of short-period, high-yield officinal plantation of C.

针对三尖杉生长缓慢的生物学特性，设置了有关苗木培育、幼林栽培和采收利用等试验，并结合生产经验，研究了三尖杉优质苗木培育、短周期药用林高产栽培和采收利用技术体系。

Mathematical model of the cavity of three-tipped cycloidal pump was established, and the structure and characteristics of the novel three-tipped cycloidal pump were analyzed.

论述了三尖摆线的形成及其参数方程，并付其特性进行了研究，建立了三尖摆线泵型腔的数学模型，分析了新型三尖摆线泵的结构和特性。

Her chest x-ray films Panels A and showed a cardiothoracic ratio of 1, splaying of the carina, and cardiac enlargement posterior to the ertebral bodies.

经胸超声示：左室小，紧挨着巨大的右心，三尖瓣前叶及隔叶下移，房化右室及重度三尖瓣返流。

An insect resembling a member of the order Coleoptera.

三尖一种有三尖的器官或部分，尤指三尖齿

Results In univariate analysis, atrial fibrillation, huge left atrium, long course of left-sided valve diease, degradation of left heart function （LVEF 〈0.50）, tricuspid rheumatic pathological change, enlarged right atrium and single mitral valvar disease were significant risk factors of TR devdopment.

结果单因素分析显示心房纤颤、巨大左房、左心瓣膜病病程长、左心功能低下（LVEF〈0.50）、右房增大（≥50mm）、三尖瓣风湿性病变及单纯二尖瓣病变是继发性TR进行性加重的危险因素；多因素分析显示心房纤颤、巨大左房、左心瓣膜病病程长及三尖瓣风湿性病变是继发性TR进行性加重的危险因素；远期随访显示，B组心功能改善明显优于A组，TR程度明显低于A组，C组术后无1例发生TR。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。