5-氟尿嘧啶短肽的合成及其抗肿瘤活性研究

5-氟尿嘧啶乙酸对-硝基苯酯和5-氟尿嘧啶丙酸对-硝基苯酯分别与三种二肽反应,制备了五个5-氟尿嘧啶二肽(4 a-e)。以5-氟尿嘧啶的氨基酸对-硝基苯酯(2 a-c)分别和三种二肽反应,制得四个5-氟尿嘧啶三肽(5 a-d)。产物经元素分析、NMR、IR和UV鉴定。初步动物试验表明:5-氟尿嘧啶丙酰甘-苯丙二肽,5-氟尿嘧啶乙酰甘-甘-苯丙三肽和5-氟尿嘧啶乙酰缬-亮-甘三肽对小白鼠移植性艾氏腹水癌有一定的抑制作用。     

5-氟尿嘧啶短钛的合成及其抗肿瘤活性研究

5-氟尿嘧啶乙酸对-硝基苯酯和5-氟尿嘧啶丙酸对-硝基苯酯分别与三种二肽反应,制备了五个5-氟尿嘧啶二肽(4aα-e).以5-氟尿嘧啶的氨基酸对-硝基苯酯(2a-c)分别和三种二肽反应,制得四个5-氟尿嘧啶三肽(5A-d).产物经元素分析,NMR,IR和UV鉴定.初步动物试验表明:5-氟尿嘧啶丙酰甘-苯丙二肽,5-氟尿嘧啶乙酰甘-甘-苯丙三肽和5-氟尿嘧啶乙酰缬-亮-甘三肽对小白鼠移植性艾氏腹水癌有一定的抑制作用.     

固相合成法制备组氨酸-苯丙二肽及其自组装研究

本文以组装性能良好的苯丙氨酸二肽(FF)为母体分子,用组氨酸对其进行化学修饰,通过多肽固相合成法合成了组氨酸-苯丙二肽(HisFF)凝胶因子。合成的HisFF分子通过质谱(MS)、核磁共振(NMR)和液相色谱(HPLC)方法测试确定精确的结构和纯度。HisFF聚集体的形貌结构通过透射电子显微镜(TEM)和扫描电子显微镜(SEM)观察。HisFF分子在甲苯、氯仿和乙酸乙酯溶剂中形成凝胶强度不同,TEM实验结果表明纤维强度和聚集形态影响其凝胶的强度。组氨酸-苯丙二肽在多种溶剂中,通过不同组装方法可以组装成各种各样的纳米结构。例如,HisFF在丙酮、甲醇和乙酸乙酯溶剂中可组装成纳米颗粒、纳米管和螺旋状纳米纤维;组氨酸-苯丙二肽先经HFIP溶解再通过溶剂稀释后,可得到不同直径的纳米纤维。但是在四氢呋喃、乙醇和乙腈溶剂中,两种方法组装的形貌几乎无变化。     

N-烷氧基苯丙-脯环二肽的一种新合成法

环二肽如L-组-L-脯环二肽、L-脯-L-羟脯环二肽等广泛存在于自然界,同时发现这些环肽显示出不同的生理活性.自然界存在的环肽中,常常包含一些非核糖体氨基酸,而这些结构往往是产生活性的重要结构单元.本研究应用脯氨酸为主要原料,在与α-烷氧亚氨苯丙酰氯反应生成N-α-烷氧亚氨苯丙酰脯氨酸后,再用氯化亚砜处理,得到对应的酰氯,E-构型肟N作为亲核试剂进攻酰氯环合得到N-烷氧基的盐,随后重排得到N-烷氧环二肽.其结构均通过IR,1H NMR,13C NMR,1H-1HNMR,MS和元素分析予以确认.研究发现,环化用有机碱如三乙胺催化时,所得环肽常常是消旋体,在没有碱存在时,得到的环肽具有旋光性.可能的原因是,前者是按烯酮机理环合的,后者是按加成-消去机理环合的.     

高效液相色谱/电喷雾-离子阱-飞行时间质谱分析鉴定中药虎杖中的主要化学成分

建立了快速、准确鉴别中药虎杖中化学成分的液相色谱-质谱法。采用高效液相色谱/电喷雾-离子阱-飞行时间质谱(HPLC/ESI-IT-TOF MS)对蒽醌类以及羟基二苯乙烯类对照品,包括大黄素、大黄酚、大黄素甲醚、大黄酸、芦荟大黄素和虎杖苷进行了分析,总结其多级裂解规律。建立了虎杖甲醇提取物的液相色谱分离条件及质谱检测条件,根据负离子模式下获得的各组分多级质谱数据,对比对照品碎裂特征并参考文献,对主要色谱峰进行指认,共鉴别了10个化合物,包括白藜芦醇-4′-O-葡萄糖苷、虎杖苷、大黄素-8-O-葡萄糖苷、白藜芦醇、决明松-8-O-葡萄糖苷、大黄素-1-O-葡萄糖苷、决明松-8-O-(6′-乙酰基)葡萄糖苷、大黄素甲醚-8-O-葡萄糖苷、大黄素甲醚-8-O-(6′-乙酰基)葡萄糖苷和大黄素,其中决明松-8-O-(6′-乙酰基)葡萄糖苷和大黄素甲醚-8-O-(6′-乙酰基)葡萄糖苷为虎杖中新发现的成分。研究结果表明,在中药化学成分研究工作中,采用电喷雾-离子阱-飞行时间质谱可提高中药化学成分的分析效率并有利于新化合物的发现和鉴别。     

环二肽合酶生物合成途径研究进展

二酮哌嗪类化合物(DKPs)的特征结构是由两个α-氨基酸通过肽键缩合而成的环二肽(CDPs),稳定的六元环骨架结构使DKPs在药物化学中成为一个重要的药效团,表现出丰富的生物活性.合成可作为药物先导物的DKPs已日益引起人们的关注,其中,开展生物合成研究是拓宽其化学结构多样性的一个有效途径.与早期阐明的非核糖体肽合成酶(NRPSs)生物合成途径不同,环二肽合酶(CDPSs)以氨酰-t RNAs(aa-t RNAs)作为底物合成环二肽,其后修饰过程发生在环二肽形成之后.目前国内外已研究的经CDPS途径合成的二酮哌嗪类化合物报道了6例.对近年来环二肽合酶(CDPSs)生物合成途径相关研究进展进行了综述.     

配体间相互作用研究: 氨基酸与二肽配体形成 质子复合物的稳定性

用pH电位滴定法测定了苯丙氨酰亮氨酸(PL)与甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、亮氨酸(Leu)、异亮氨酸(Ile)、苯丙氨酸(Phe)在离子强度为0.1mol/L(NaNO~3),(25.0±0.1)℃时形成质子复合物的稳定常数,并对苯丙氨酰亮氨酸与六种氨基酸相互作用体系进行了量子化学和分子力学计算。从配体间弱相互作用的观点,讨论了二肽配体对氨基酸分子的识别。结果表明,二肽与氨基酸配体间的结合主要受到配体间静电、氢键作用的控制,同时受到范德华力和键间排斥能等弱相互作用的影响。     

配体间相互作用研究: 氨基酸与二肽配体形成 质子复合物的稳定性

用pH电位滴定法测定了苯丙氨酰亮氨酸(PL)与甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、亮氨酸(Leu)、异亮氨酸(Ile)、苯丙氨酸(Phe)在离子强度为0.1mol/L(NaNO~3),(25.0±0.1)℃时形成质子复合物的稳定常数,并对苯丙氨酰亮氨酸与六种氨基酸相互作用体系进行了量子化学和分子力学计算。从配体间弱相互作用的观点,讨论了二肽配体对氨基酸分子的识别。结果表明,二肽与氨基酸配体间的结合主要受到配体间静电、氢键作用的控制,同时受到范德华力和键间排斥能等弱相互作用的影响。     

新型桥连双锌配合物的合成和结构

合成了二(2-苯并咪唑亚甲基)胺及其副产物[2，5-二(苯并咪唑亚甲基)环二肽 ]的混合配体与助Zn(Ⅱ)的双核超氧化物歧化酶模型化合物．进行了元素分析、紫 外和红外表征；对配合物采用X射线衍射方法测定了晶体结构，并采用G94W程序对 副产物[2，5—二(苯并咪唑亚甲基)环二肽]进行了量子化学计算．     

海洋放线菌Streptomyces sp. V5产生的一个新的八元环内酯

海洋放线菌Streptomyces sp. V5分离自南中国海红树根部土壤, 从其培养液分离获得一个新的八元环内酯octalactin C (A), 以及四个已知化合物2-甲基-3-呋喃甲酸(B)、环(脯-亮)二肽(C)、环(丙-缬)二肽(D)和尿嘧啶(E). 通过完整的波谱数据解析了它们的结构.     

南海红树林内生真菌No．ZZF71代谢产物研究

由于海洋环境的特殊性和微生物在生态系统的功能,海洋微生物已经发展出独特的代谢方式,提供了在陆地微生物中未遇到过的代谢产物。研究海洋微生物的活性物质,不但能发现结构新颖的化合物,丰富和发展有机化学理论,而且为寻找新的强效活性药物及其它有用物质提供了一个重要途径[1     

Growth format, electronic architecture, magnetic, and optical properties of aromatic cyclo-Cu3Au3 homotops

Bimetallic Cu(3)Au(3) clusters have been investigated using electronic structure calculation techniques (DFT) to understand their electronic, magnetic, and optical properties as well as the geometrical structures. The most stable homotop is the planar cyclo-[Cu(3)(micro-Au)(3)] form consisting of a triangular positively charged Cu(3) structural core with negatively charged Au atoms occupying exposed positions. This structure is characterized by the maximum number of heterobonds and peripheral positions of Au atoms. Possible growth formats of the cyclo-[Cu(3)(micro-Au)(3)] homotops have been explored following both the edge-capping and the stepwise metal atom substitution mechanism. The bonding pattern along with the density of states (DOS) plots of the cyclo-[Cu(3)(micro-Au)(3)] homotop are thoroughly analyzed and compared with those of the pure cyclo-[Cu(3)(micro-Cu)(3)] and cyclo-[Au(3)(micro-Au)(3)] clusters. Particular attention was paid on the stability of these bimetallic clusters in relation with the ring-shaped electron density distribution (aromaticity). It was found that all 3-membered metal rings exhibit significant aromatic character, which was verified by a number of established criteria of aromaticity, such as structural, energetic, magnetic (NICS profiles), and out-of-plane ring deformability criteria. The NICS (1) values correlate well with the out-of-plane ring deformation energy. Finally, a comprehensive analysis of the optical spectra of the CuAu, Cu(2), and Au(2) diatomics and the cyclo-[Cu(3)(micro-Au)(3)], cyclo-[Cu(3)(micro-Cu)(3)], and cyclo-[Au(3)(micro-Au)(3)] clusters placed the electronic assignments of the optical transitions on a firm footing.     

The versatile reactivity of cyclo-(P5tBu4)- with complexes of the nickel triad

Na[cyclo-(P(5)tBu(4))] (1) reacts with [NiCl(2)(PEt(3))(2)] and [PdCl(2)(PMe(2)Ph)(2)] with elimination of tBuCl and formation of the corresponding metal(0) cyclopentaphosphene complexes [Ni{cyclo-(P(5)tBu(3))}(PEt(3))(2)] (2) and [Pd{cyclo-(P(5)tBu(3))}(PMe(2)Ph)(2)] (3). In contrast, complexes with the more labile triphenylphosphane ligand, such as [MCl(2)(PPh(3))(2)] (M=Ni, Pd), react with 1 with formation of [NiCl{cyclo-(P(5)tBu(4))}(PPh(3))] (4) and [Pd{cyclo-(P(5)tBu(4))}(2)] (5), respectively, in which the cyclo-(P(5)tBu(4)) ligand is intact. In the case of palladium, the cyclopentaphosphene complex [Pd{cyclo-(P(5)tBu(3))}(PPh(3))(2)] (6) in trace amounts is also formed. However, [Ni{cyclo-(P(5)tBu(4))}(2)] (7) is easily obtained by reaction of two equivalents of 1 and one equivalent of [NiCl(2)(bipy)] at room temperature. Complex 7 rearranges on heating in n-hexane or toluene to the previously unknown [Ni{cyclo-(P(5)tBu(4))PtBu}{cyclo-(P(4)tBu(3))}] (8), which presumably is formed via the intermediate [Ni{cyclo-(P(5)tBu(4))}{cyclo-(P(4)tBu(3))PtBu}], which, after an unexpected and unprecedented phosphanediide migration, gives 8, but always as an inseparable mixture with 7. In the reaction of 1 with [PtCl(2)(PPh(3))(2)], ring contraction and formation of [PtCl{cyclo-(P(4)tBu(3))PtBu}(PMe(2)Ph)] (9) is observed. Complexes 3-5 and 7-9 were characterised by (31)P NMR spectroscopy, and X-ray structures were obtained for 5-9.     

Syntheses and chemistry of hypervalent cyclo-R4Sb4, cyclo-(RSbE)n[R = 2-(Me2NCH2)C6H4, E = O, S] and precursors

The cyclostibane R(4)Sb(4)(1)(R = 2-(Me(2)NCH(2))C(6)H(4)) was synthesized by reduction of RSbCl(2) with Mg in THF or with Na in liquid NH(3). The reaction of 1 with [W(CO)(5)(THF)] gives the stibinidene complex RSb[W(CO)(5)](2)(2). RSbCl(2) and (RSbCl)(2)E [E = O (6), E = S (8)] react with KOH or Na(2)S in toluene/water to give the heterocycles (RSbE)(n)[E = O, n= 3 (3); E = S, n= 2 (4)]. The chalcogeno-bridged compounds of the type (RSbCl)(2)E [E = O (6), E = S (8)] were synthesized by reaction of RSbCl(2) with KOH or Na(2)S in toluene/water, but also by reaction of RSbCl(2) with the heterocycles (RSbE)(n). The compounds (RSbI)(2)O (7) and (RSbBr)(2)S (9) were prepared via halogen-exchange reactions between (RSbCl)(2)E and NaI (E = O) or KBr (E = S) or by reactions between RSbI(2) and KOH or RSbBr(2) and Na(2)S. The reaction of cyclo-(RSbS)(2) with W(CO)(5)(THF) in THF results in trapping of the cis isomer in cyclo-(RSbS)(2)[W(CO)(5)](5). The solution behaviour of the compounds was investigated by (1)H and (13)C NMR spectroscopy. The molecular structures of compounds 1-7 and 9 were determined by single-crystal X-ray diffraction.     

In situ synthesis of nickel tiara-like clusters with two different thiolate bridges

Four nickel clusters, cyclo-[{Ni(μ-S(i)Pr)(μ-SMe)}(6)] (1), cyclo-[{Ni(μ-StBu)(μ-SMe)}(6)] (2), cyclo-[{Ni(μ-S(i)Pr)(μ-SEt)}(6)] (3) and cyclo-[{Ni(μ-StBu)(μ-SEt)}(10)] (4), based on thiolate ligands have been successfully synthesized and characterized by elemental analysis, FT-IR spectra, UV-vis-NIR spectra, powder X-ray diffraction and single-crystal X-ray diffraction. Intriguingly, the SMe and SEt ligands are generated from solvothermal in situ ligand synthesis through the cleavage of the S-S bond respectively. The four nickel thiolate clusters exhibit tiara-like frameworks consisting of two different types of thiolate ligands.     

南海红树内生真菌1947号次级代谢产物的研究

红树植物是一类生长于潮间带的乔灌木的通称。近年来,国内外对红树内生真菌代谢产物的研究呈快速发展趋势。本课题组自上世纪90年代以来开始研究南海红树内生真菌代谢产物,迄今已从南海红树内生真菌分离得到许多有意义的代谢产物[1-5]。编号为1947号的内生真菌分离自香港江口红     

Linear and cyclic polysilanes containing the bis(trimethylsilyl)amino group: synthesis,reactions, and spectroscopic characterization

The reaction of linear (Si(n)Cl(2)(n)(+2); n = 3-5) and cyclic (Si(5)Cl(10)) perchloropolysilanes with 1 or 2 equiv of LiN(SiMe(3))(2) results in the formation of the bis(trimethylsilyl)amino derivatives (Me(3)Si)(2)NSi(3)Cl(7) (1), (Me(3)Si)(2)NSi(4)Cl(9) (2), (Me(3)Si)(2)N(SiCl(2))(n)N(SiMe(3))(2) (n = 3, 4; n = 4, 5; n = 5, 6), cyclo-(Me(3)Si)(2)NSi(5)Cl(9) (7), and cyclo-[(Me(3)Si)(2)N](2)Si(5)Cl(8) (8). 1-8 easily can be hydrogenated with LiAlH(4) to give the corresponding amino and diamino polysilanyl hydrides. The monosubstituted and cyclic compounds 1, 2, 7, and 8 additionally afford Si-Si bond scission products, which cannot be separated in all cases. Chloro- and dichloro derivatives of Si(3)H(8), n-Si(4)H(10), and n-Si(5)H(12) are obtained from the corresponding aminosilanes and dry HCl. All compounds were characterized by standard spectroscopic techniques. For Si-H derivatives the coupled (29)Si NMR spectra were analyzed to obtain an unequivocal structural proof.     

Studies on the Constituents of Ganoderma Lucidum

The methanolic extract of fruit bodies of cultivated Ganoderma lucidum was separated by silica gel column chromatography and preparative thin-layer chromatography to give ten compounds. On the basis of spectral analysis, chemical procedures and gas chromatography, d-mannitol (1), ergosta-7, 22-dien-3β-yl palmitate (2), ergosterol (3), ergosta-7, 22-dien-3β-ol (4), 5α-lanosta-7,9(11),24-trien-3β,26-diol (5), ergosterol peroxide (6), 24,25,26-trihydroxy-5α-lanosta-7,9(11)-dien-3-one (7), 5α-lanosta-7,9(11)-dien-3β,24,25,26-tetraol (8) and 8,9-epoxyergosta-5,22-dien-3β,15-diol (9) were identified. Among these compounds, 8,9-epoxyergosta-5,22-dien-3β,15-diol was first separated from Ganoderma lucidum.     

An antimicrobial diketopiperazine alkaloid and co-metabolites from an endophytic strain of Gliocladium isolated from Strychnos cf. toxifera

From an endophytic strain of Gliocladium sp. isolated from the Amazonian plant Strychnos cf. toxifera, we obtained the diketopiperazine alkaloid cyclo-(glycyl-L-tyrosyl)-4,4-dimethylallyl ether (1), the steroids ergosterol (2), ergosterol peroxide (3), cerevisterol (4) and the citric acid (5). The AcOEt extract of the fermented broth by Gliocladium sp. showed potent activity against the cancer cell lines MDA-MB435 (human breast cancer cells), HCT-8 (human colorectal cancer cells) and SF-295 (human glioblastoma cancer cells). Compound 1 exhibited a strong antimicrobial activity against Micrococcus luteus at a concentration of 43.4?μM.