土槿皮新二萜成分的研究Ⅰ.土槿甲酸和土槿乙酸的化学结构测定

土槿皮是松科植物金钱松的树皮,具有抗真菌作用.自土槿皮中分得两种成分土槿甲酸和土槿乙酸,均系新的二萜化合物.经化学、谱学以及X射线衍射等方法证明其结构分别为1和2.     

利用质子COSY-45来确定土槿皮酸类衍生物偶合常数的相对符号

报导了用2D-COSY-45谱确定土槿皮酸B(2)及其衍生物(1)中具有AMX自旋体系的偶合常数相对符号, 从(1)获得的结果与以Pseudo-INDOR技术获得的结果一致, 因此COS6-45不仅可用来观察质子基团间的偶合关系, 而且还可判断三核自旋偶合体系偶合常数的相对符号, 并可推广到ABX自旋体系中去.     

土槿皮新二萜成分的研究 Ⅳ.土槿丁酸和土槿戊酸的分离和结构测定

从土槿皮(Pseudolarix kaempferi,Gord.)中分离到两个新二萜酸,命名为土槿丁酸(1)和土槿戊酸(2).经理化性质和对它们的IR、~1HNMR和~(13)CNMR、MS数据的分析,鉴定1为18-羟-对映-贝壳衫-15-烯-17-羧酸;2为对映-贝壳杉-15-烯-17,18-二羧酸.1的结构经X衍射得到了证实.     

薄层色谱法测定癣可净中的水杨酸和苯甲酸

癣可净是治疗癣疾的常用药之一,由土槿皮酊加苯甲酸和水杨酸制成。地方标准和制剂手册采用中和法仅可测定癣可净的总酸量。本文提出的薄层色谱法可测定癣可净中苯甲酸和水杨酸的含量。 实验部分 (一)仪器和药品 Shimadzu CS-930双波长薄层扫描仪(日本Shimadzu),毛细管(美国Druammond Sci.Co.),所用试剂除硅胶G为化学纯外均为分析纯。 (二)标准溶液的配制 精确称取30.00mg苯甲酸,15.00mg水杨酸,以10ml无水乙醇溶解并定     

土槿皮新二萜成分的研究 IV: 土槿丁酸和土槿戊酸的分离和结构测定

从土槿皮(Pseudolarix kaempferi, Gord.)中分离到两个新二萜酸, 命名为土槿丁酸(1)和土槿戊酸(2), 经理化性质和对它们的IR、^1H NMR、^1^3C NMR、MS数据的分析, 鉴定1为 18-羟-对映-贝壳杉-15-烯-17-羧酸; 2为对映-贝壳杉-15-烯-17, 18-二羧酸. 1的结构经X衍射得到了证实.     

土槿皮三萜成分的研究

从土槿皮(Pseudolarix kaempferi, Gord.)中分到两个三萜成分, 经化学和光谱方法证明, 其一为具有羊毛甾烷母核的新三萜-3氧代-羊毛甾-7,23,25-三烯-23,26-环氧-27-羧酸, 命名为金钱松呋喃酸(1), 另一个为白桦脂酸(2), 此外, 还分到β-谷甾醇和β-谷甾醇-β-D-葡萄糖苷。     

土槿皮酸类化合物的质谱研究

本文系统地研究了土槿皮甲酸、乙酸和丙酸及其衍生物的质谱.通过质谱-结构关系的分析、高分辨质谱及亚稳数据的测定,阐明了它们在电子轰击下的裂解反应机制.     

土槿皮新二萜成分的研究 Ⅲ.土槿甲酸苷和土槿乙酸苷的分离及结构测定

前报报道了土槿皮(Pseudolarix kaempferi,Gord.)中抗真菌有效成分新二萜酸——土槿甲、乙、丙和丙_2酸的结构研究。现自土槿皮中继续分离得苷1和苷2,经化学和物理方法证明1为土槿甲酸-β-D-葡萄糖苷,2为土槿乙酸-β-D-葡萄糖苷。 1为白色粉末状固体,难溶于乙醚等低极性溶剂中,亦难溶于水和碳酸氢钠水溶液中,易溶于乙酸乙酯和醇中。IR示有羟基、酯基及双键,但无羧基吸收峰。~1H NMR与土槿甲酸的相似,但明显出现了糖的质子信号。糖端基质子信号δ5.66(d,J=7.5Hz),其位移值比糖接在醇羟基上的低。结合IR测知无羧基及在碳酸氢钠水溶液中不溶解,推测糖接在羧基上。质     

土槿皮新二萜成分研究——Ⅱ.土槿丙2酸的结构证明和土槿甲酸、土槿乙酸、土槿丙酸和土槿丙2酸的结构沟通

前报报道了土槿甲酸(1)和土槿乙酸(2)的化学结构.土槿皮中的另一成分土槿丙酸(3)已证明为去乙酰基土槿乙酸.我们将柱层析分去1,2后的洗脱流分,重复进行硅胶柱层析,除获得3外,还得到一个R_f值与3相近但具有双熔点的成分,定名土槿丙₂酸,经鉴定为去甲基土槿乙酸(4).前报1和2的碳架系通过土槿甲酸结晶的X射线衍射分析确定.本文通过沟通1～4的结构关系,即由1经数步氧化反应,分别证明产物为2,3和去乙酰基去甲基土槿乙酸     

土槿甲酸的分子结构及晶体结构的研究

土槿甲酸是抗真菌土槿皮酸的成分之一.晶体属四方晶系,空间群P422晶胞参数a=b=8.956Å,c=51.834Å,α=β=γ=90°,z=∑a_n=4564.土槿甲酸的粗结构模型和化学结构式通过直接法测定.     

狭叶百部中新生物碱的结构研究

狭叶百部(Stemona mairei Lévl)为百部科植物,产于我国云南省西北部金沙江沿岸的山坡上,民间用于止咳与润肺等。作者从云南省     

环氧乙烷-环氧丙烷无规共聚醚链结构的核磁共振研究

本文用NMR波谱方法研究了无规共聚醚(EPO)的链结构。首先对EPO的~1H和~(13)CNMR谱进行了讨论。并从序列结构随环氧丙烷(PO)含量的改变,分析了EPO的二元组序列和三元组序列结构,从~(13)C实验谱中归纳出EPO的取代基参数(SCS),清楚地揭示了EPO的~(13)C谱,SCS参数和序列结构之间的关系,在此基础上计算了EPO系列共聚物的序列分布和数均序列长度。     

镧系金属有机配合物的研究——ⅩⅠⅩ.二茂型氯化钇和镥的~1H和~(13)C核磁共振谱

核磁共振法已深入了金属有机化学领域的研究。其中,对于二茂夹心化合物,已用~1H和~(13)C 核磁共振方法研究了取代基影响环戊二烯基配位体的屏蔽效应。而用于研究稀土环     

二维接力HOHAHA和—维多重接力COSY研究苷类化合物的结构

苷类化合物的糖体质子大多相互有自旋偶合作用,构成一个复杂的自旋系统。糖体端基质子(H-1)NMR 信号大多为双峰,出现在较     

Synthesis and Characterization of 2,6-Bis(imino)phenoxy Cobalt Complexes

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Characterisation of uniformly 13C, 15N labelled bacteriochlorophyll a and bacteriopheophytin a in solution and in solid state: complete assignment of the 13C, 1H and 15N chemical shifts

In this investigation we report a complete assignment of (13)C, (1)H and (15)N solution and solid state chemical shifts of two bacterial photosynthetic pigments, bacteriochlorophyll (BChl) a and bacteriopheophytin (BPheo) a. Uniform stable-isotope labelling strategies were developed and applied to biosynthetic preparation of photosynthetic pigments, namely uniformly (13)C, (15)N labelled BChl a and BPheo a. Uniform stable-isotope labelling with (13)C, (15)N allowed performing the assignment of the (13)C, (15)N and (1)H resonances. The photosynthetic pigments were isolated from the biomass of photosynthetic bacteria Rhodopseudomonas palustris 17001 grown in uniformly (13)C (99%) and (15)N (98%) enriched medium. Both pigments were characterised by NMR in solution (acetone-d(6)) and by MAS NMR in solid state and their NMR resonances were recorded and assigned through standard liquid 2D (13)C-(13)C COSY, (1)H-(13)C HMQC, (1)H-(15)N HMBC and solid 2D (13)C-(13)C RFDR, (1)H-(13)C FSLG HETCOR and (1)H-(15)N HETCOR correlation techniques at 600 MHz and 750 MHz. The characterisation of pigments is of interest from biochemical to pharmaceutical industries, photosynthesis and food research.     

1H and 13C NMR spectra of N-substituted morpholines

(1)H and (13)C NMR data for N-substituted morpholines 1-20 were measured using 1D (DEPT, 1D NOE difference) and 2D NMR spectroscopic methods including (1)H-(1)H COSY, long-range (1)H-(1)H COSY, NOESY, gHMBC and gHMQC experiments. At room temperature the (1)H NMR spectra of protonated compounds 2 and 9 show the chair conformation for the morpholine ring. Spin-spin coupling constants were deduced from the resolution-enhanced proton spectra.     

Detailed assignments of 1H and 13C NMR spectral data of 13 beta-substituted cycloenones

Detailed assignments of (1)H and (13)C NMR spectral data for 13 beta-substituted cycloenones are reported. The assignments are based on 1D (1)H and (13)C NMR and on 2D shift-correlated ((1)H,(13)C-HMQC and HMBC), J-resolved and COSY and double irradiation experiments.     

Unambiguous NMR spectral assignments of salvinorin A

The complete assignments of the (1)H and (13)C NMR spectra of the hallucinogenic neoclerodane diterpenoid salvinorin A were determined in three different NMR solvents using HSQC, HMBC and COSY. Solvent systems are described that allow the resolution of all (1)H signals. Virtual coupling was observed for the protons at C-2, C-3 and C-4 in the 600 MHz (1)H spectrum in CDCl(3). The complete assignments of the (1)H and (13)C NMR spectra of salvinorin B are also reported.     

Synthesis and complete assignment of the 1H and 13C NMR signals of some oxopyrancoumarin and oxofuropyrancoumarin derivatives

The synthesis of four pyranocoumarins starting from phloroglucinol and the complete (1)H and (13)C NMR assignment of seven pyranocoumarins has been performed using 1D and 2D NMR techniques including COSY, HMQC and HMBC experiments.