胆红素与胆汁酸盐作用时的构象变化

利用PPP-SCF-CI-DV量子化学程序拟合胆红素以及胆汁酸盐-胆红素水溶液的UV和CD谱, 借以研究胆红素及其与胆汁酸盐复合物的构象性质。发现胆红素与胆汁酸盐作用时, 两个双吡咯生色团的扭角由104°变成112°, 仍保持形成分子内氢键的状态, 其UV及CD谱两个吸收峰间隔的增宽, 主要是胆红素的一侧双吡咯生色团与胆汁酸盐呈疏水性结合的原故; 二羟基和三羟基胆汁酸盐所形成的二元复合物园二色谱的差别, 是胆红素的对映选择性结合造成的。     

STUDIES ON STEROIDAL PLANT-GROWTH REGULATORS (ⅩⅦ)——A NEW SYNTHESIS OF HOMOBRASSINOLIDE AND (22S,23S)-22,23-EPI-HOMOBRASSINOLIDE

Homobrassinolide (2) and (22S, 23S)-22,23-epi-homobrassinolide (4) were synthesized fromstigmasterol in seven steps respectively in 4.7% and 24.1% overall yields. The ratio of 2 to 4is 1:5. The key step is the highly regioselective formation of the B--homo-7-oxa-lactone ringby oxidation of an enol silyl ether with 3--chloro-peroxybenzoic acid.     

雷公藤内脂四醇的晶体结构

雷公藤系卫矛科植物( Tripterygium wlfordii Hook. f) , 1972) 年,Kupechan从分得三种环二萜内酯类化合物,显示出较强的抗白血压病活性。为了寻找低毒有效的类似物,本文从雷公藤根皮乙醇提取物的氯仿溶出部分,反复经硅胶柱层析分理,得到一种新的环氧二萜酯;雷共藤内酯四醇(Tripletraolide)。在乙酸乙酯重结晶,得无色长极状晶体,m.p.258~260℃。经高分辩质谱确定其分子为C~0H~26O~8,M~r=394.2。     

人体体液中游离脂肪酸的GC-MS定量测定

从人血清、血浆、乳汁等体液中萃取出游离脂肪酸与酯化态脂肪酸混合物,经薄层层析分离、甲酸化后,以十五(烷)酸作内标进行GC-MS(Gas Chromatography-Mass Spectrometry)定量测定,获得游离脂肪酸含量。     

亚磷酸三乙酯硫化反应历程的GC/MS研究

用气相色谱-质谱联用技术研究了亚磷酸三乙酯和亚磷酸三苯酯与硫反应的机理.研究证明,硫与三价磷化合物的反应只发生在液相状态.     

高效液相色谱法快速,灵敏测定尿中3—甲基组氨酸含量

本文报道用柱前衍生高液相色谱法快速，灵敏地测定尿中３－甲基组氨酸（３ＭＨ）。采用含３０％乙腈的１０ｍｍｏｌ／Ｌ磷酸钠缓冲液（ｐＨ＝７．５）为流动相，等梯度洗脱，１０ｍｉｎ内即可分析一个样品；在２０－３０００ｐｍｏｌ范围内，３ＭＨ线性相关系数为０．９９８６，相对标准偏差为２．３％（批内）和４．５％（批间）；并测定了１０名正常人尿中的３ＭＨ含量。     

A New Deoxygenation Method for Taxanes Using Hypophosphorous Acid

An efficient and practical radical chain deoxygenation method by phosphorus centered radicals generated from hypophosphorous acid was developed in the synthesis of analogues of paclitaxel.     

Synthesis of thiourea derivatives as CCR4 antagonists

A series of thiourea derivatives have been synthesized. Their structures were confirmed by MS and 1H NMR. Several compounds showed potent activities as antagonists of CCR4 receptor.     

A Novel Ursane Triterpene from Rubus swinhoei

As a part of investigation on the plant of Rubus, we studied the chemical constituents of the roots of R. swinhoei. A novel ursane triterpene, named swinhoeic acid, was isolated and converted into its methyl-ester with CH2N2. This paper deals with its structure elucidation.Figure 1 The structure of 1 and 1a Figure 2 The key HMBC correlationsCompound 1a, was obtained as white powder, [?] - 66 (c 0.1, CHCl3). Its molecular formula was assigned as C31H48O5 by HR-EIMS ([M]+ m/z 500.3487…     

Gnetupendin C, a New Stilbene Dimer from the Lianas of Gnetum Pendulum

Continuous investigation on stilbenoids from the lianas of Gnetum pendulum1 resulted in the isolation of a new dimer, Gnetupendin C (1), a cis-2, 3-dihydrobenzofuran dimer of resveratrol and oxyresveratrol.Gnetupendin C (1) was obtained as yellowish amorphous power, [(] -220.0 (c 0.100, MeOH). UV (c 0.02, MeOH) (max (log (): 222 (4.5), 288 (sh), 310 (sh), 327 (4.4) nm. The high resolution EIMS, m/z 470.1344, agreed with a molecular formula of C28H22O7 (requires 470.1366) and the 1H NM…