莲子草假隔链格孢毒素的分离纯化与结构鉴定

从莲子草假隔链格孢(Nimbya alternantherae)中分离纯化了一种毒素物质, 并对其进行了结构鉴定, 为研究其致病机理及进一步的化学合成奠定了基础.     

纳米金-钛酸纳米管复合材料的合成与表征

以氯金酸和钛酸钠米管(NTA)为原料,柠檬酸三钠为稳定剂,硼氢化钠为还原剂,于室温条件下合成了一种金纳米颗粒-钛酸纳米管(GNPs-NTA)复合纳米材料;利用红外光谱仪、透射电镜、X射线粉末衍射仪等分析了产物的化学键合特征、微结构及相组成,并考察了产物对辣根过氧化酶(HRP)结构和生理活性的影响.结果表明,合成的纳米金颗粒粒径(平均5.3nm)分布窄,且均匀分布于钛酸纳米管表面.此外,HRP与GNPs-NTA复合纳米材料充分振荡混合后仍能保持其二级结构不变,有利于保持其生理活性.     

苔色醛甲酸甲酯的合成

间苯二酚大环内酯是一类具有多种生理活性的天然产物,药理实验表明,此类天然产物具有抗肿瘤、抗菌、抗疟疾以及抗动物体内P388白血病等活性[1].20世纪80年代Nair等从海洋生物红树上的子囊菌类(Aigialus parvus)草中提取了具有抗疟疾活性的化合物Hypothemycin(IC50 80μg/mL)[2].2002年,在Aigialusparvus BCC5311的主要二次代谢物中又分离出五个新的天然产物Aigiacomycin A～E,是一类具有十四元环的间苯二酚类大环内酯,并进行了相应的生物药理活性试验[3].苔色醛甲酸酯(1)是合成Aigiacomycin A～E的重要中间体.本文对Vlattas[4]方法作了改进,以乙酰乙酸甲酯为原料,经芳环化、羟基酯化、氧化、水解、甲醚化等五步反应,合成了苔色醛甲酸甲酯(1)(4,6-二甲氧基-2-甲酰基苯甲酸甲酯).具有操作简便,产率较高等优点.     

二环己酮草酰二腙桥联的双核铜(Ⅱ)配合物的合成、表征及杀菌活性

合成了三种新的二环己酮草酰二腙 (BCO)桥联的双核铜 (Ⅱ )配合物 [Cu2 (BCO)L2 ](ClO4 ) 4;其中L代表乙二胺 (en) ,1,2 -丙二胺 (ap)和 1,3-丙二胺 (pn) .经元素分析、摩尔电导以及红外光谱和电子光谱等方法对这些配合物进行了表征 ,推定了配合物的组成和结构 ,研究了三种配合物的杀菌活性 .     

E-橙皮素肟类化合物的合成及对SGC-7901的细胞活性

以天然橙皮素(1)为原料,经选择性甲基化和异戊烯基化半合成得到了桃皮素(2)和7-O-异戊烯基橙皮素(3).1~3分别与盐酸羟胺、盐酸甲氧胺、盐酸苄氧胺反应合成了9个E构型的橙皮素肟类化合物.所合成产物通过NMR,HR-ESI-MS方法进行了结构确证.噻唑蓝(MTT)蛋白染色法体外抑制肿瘤增值活性测试发现部分化合物对胃癌细胞SGC-7901有明显的抑制活性.     

(±)-3,5-二羟基-7,4′-二甲氧基二氢黄酮醇和(±)-3,5,7-三羟基-4′- 甲氧基二氢黄酮醇全合成

二氢黄酮醇是植物界所产生的次生代谢产物[1],除抗菌活性外,它们被广泛应用于医药化工领域[2].3,5-二羟基-7,4′-二甲氧基二氢黄酮醇和3,5,7-三羟基-4′-甲氧基二氢黄酮醇从多种药用植物中分离得到[3,4].本文利用以2,4,6-三羟基苯乙酮和茴草醛为起始原料,经选择性保护、缩合、环氧化、关环首次完成了(±)1和(±)2的全合成.合成路线如图示1所示:     

基于天然产物Mevalocidin手性中心的结构类似物的设计与合成（英文）

Mevalocidin是从Rosellinia DA092917和Fusarium DA056446菌株中分离到的一种天然产物,在4 kg/ha的高剂量下具有苗后除草活性.希望对其手性中心进行改造以提高除草活性,通过设计不同合成路线,合成了2个类似物,通过~1H NMR、~(13)C NMR及HRMS对所合成化合物的结构进行了确认.活性筛选结果表明,所合成的目标化合物不具有除草活性,说明天然产物手性中心上的甲基和羟基对其活性保持至关重要,为进一步结构修饰提供了指导.     

5′位羟基异戊烯基查尔酮类天然产物的合成及其抗菌活性研究

首次合成了Bartericin A (1), 2’,6’-二羟基-5’-(2’’-羟基-3’’-甲基-3’’-丁烯基)-4’-甲氧基查尔酮(2), Xanthohumol D (3)和Angusticornin B (4) 4个羟基异戊烯基查尔酮类天然产物.为了探讨天然产物中不同官能团对其核心骨架结构抗菌活性的影响,设计合成了衍生物6.所合成的目标产物和未知中间体化合物经过1H NMR、13C NMR、IR、HRMS进行了确证.选取大肠杆菌[CMCC(B)44102]、绿脓杆菌[CMCC(B)10104]、金黄色葡萄球菌[CMCC(B)260003]和枯草芽孢杆菌[CMCC(B)63 501],采用稀释点样法对所合成的4个天然产物及1个新型衍生物进行了抗菌活性评估.结果显示,天然产物1、4和衍生物6对革兰氏阳性菌金黄色葡萄球菌和枯草芽孢杆菌表现出了一定的抑制活性.天然产物3对枯草芽孢杆菌表现出了较为明显的抑制活性,但对其他3种菌株无抑制活性(最小抑菌浓度>200μg/mL).     

3-(噁唑-5-基)吲哚类天然产物生物活性及其衍生物的合成研究进展

3-(噁唑-5-基)吲哚类天然产物如Pimprinine,Streptochlorin等,广泛存在于海洋微生物中,因其具有多样的生物活性,在医药和农药领域中很有研究潜力.3-(噁唑-5-基)吲哚类天然产物的合成方法有很多研究报道,在吲哚结构上构建噁唑环是合成此类天然产物的关键.总结了已报道的3-(噁唑-5-基)吲哚类天然产物的生物活性,并对构建3-(噁唑-5-基)吲哚骨架的合成方法及部分主要反应机理进行了综述,探讨了3-(噁唑-5-基)吲哚类骨架作为一种优势活性结构在未来的应用前景.     

(S)-甘油醛缩丙酮的新合成方法

(S)-甘油醛缩丙酮是一种用来合成一些手性药物和具有光学活性的天然产物的重要前体,本文以L-抗坏血酸为原料,经高压氢化还原、缩合反应、氧化剂氧化等步骤合成(S)-甘油醛缩丙酮.同时考察了不同的反应条件对产品收率的影响.     

Herbarumin Ⅲ的立体选择性全合成

以正丁醛和1,5-戊二醇为起始原料, 以不对称烯丙基化、改良的Julia成烯反应和Yamaguchi内酯化为关键步骤, 通过13步反应, 立体选择性地合成了具有植物毒性的天然十元内酯化合物Herbarumin Ⅲ(3)及其差向异构体22.     

The main phytotoxic metabolite produced by a strain of Fusarium oxysporum inducing grapevine plant declining in Italy

A strain of Fusarium oxysporum was isolated from grapevine showing heavy decline disease in a vineyard of Veneto region in Italy. The fungus showed to produce phytotoxic metabolites when grown in liquid culture. The main metabolite was identified as fusaric acid produced for the first time as a phytotoxin by a strain of F. oxysporom isolated from diseased grapevine plants. Its quantification in the fungus cultures filtrates was accomplished by HPLC. When tested on tobacco by leaf-puncture assay fusaric acid at 0.5 mg/mL induced the formation of extensive necrosis.     

Expedient stereoselective synthesis of coronafacic acid through intramolecular Diels-Alder cyclization

A stereoselective synthesis of coronafacic acid, a natural component of the phytotoxin coronatin, was achieved using an intramolecular Diels-Alder reaction as the key step. The triene precursor bearing a substituted diene and a vinylketone as dienophile was synthesized and then tested in the thermal intramolecular cyclization. We have devised a new strategy to assemble the E,Z-diene through the stereoselective aldol reaction of an ester enolate followed by a stereoselective dehydration. Following the thermal cyclization, the corresponding hydrindanone thereby obtained with the desired relative stereochemistry could easily be converted into the natural product. The synthesis of the coronafacic acid was accomplished in six steps in 29% overall yield.     

Synthesis to determine the absolute configuration of (−)-pyricuol, a phytotoxin isolated from rice blast disease fungus Magnaporthe grisea

The absolute configuration of (−)-pyricuol, a phytotoxin isolated from rice blast disease fungus Magnaporthe grisea, was determined to be R by synthetic studies.     

The first synthesis of (-)-asperpentyn and efficient syntheses of (+)-harveynone, (+)-epiepoformin and (-)-theobroxide

A generally applicable strategy for the synthesis of a range of polyoxygenated cyclohexane natural products has been developed. The enantioselective syntheses of (-)-theobroxide, a polyoxygenated cyclohexane natural compound with potent growth inducing properties in potato microtubers has been achieved via a 1,2 O-silyl migration between trans-hydroxyl groups and a remote hydroxyl directed epoxidation of an enone derived from quinic acid. A thus derived alpha-iodoenone was subjected to Stille coupling with tetramethylstannane to afford the first title compound. A similar strategy enabled a route to the complete asymmetric synthesis of the acetylenic phytotoxin (+)-harveynone. By selective reduction of (-)-theobroxide, (+)-epiepoformin was also prepared in enantiopure form and similarly, stereoselective reduction of (+)-harveynone completed the first enantioselective synthesis of (-)-asperpentyn, another natural compound with antimicrobial activity.     

Pestalotiopens A and B: Stereochemically Challenging Flexible Sesquiterpene‐Cyclopaldic Acid Hybrids from Pestalotiopsis sp.

From the endophytic fungus Pestalotiopsis sp. isolated from the leaves of the Chinese mangrove, Rhizophora mucronata, two novel hybrid sesquiterpene‐cyclopaldic acid metabolites with an unusual carbon skeleton, named pestalotiopens A and B, were obtained, together with the already known phytotoxin altiloxin B. Pestalotiopen B even contains a third, triketide‐derived module. The constitutions and the absolute configurations of the new metabolites and of altiloxin B were unambiguously determined by a combination of spectroscopic methods and quantum‐chemical optical‐rotatory dispersion (ORD) and circular dichroism (CD) calculations. A biosynthetic pathway to pestalotiopens A and B is proposed with altiloxin B as one of the suggested precursors. Pestalotiopen A shows moderate antimicrobial activity against Enterococcus faecalis.     

Direct Isocoumarin Synthesis Through LDA-Promoted Addition of Acetaldehyde on Orsellinate. An Abrupt Synthesis of 6-Hydroxymellein,a Fungal Phytotoxin

The LDA-promoted addition of acetaldehyde on orsellinate gives (±) 6 -hydroxymellein, a fungal phytotoxin, with a 51% yield.     

A new total synthesis of porritoxin

A concise and efficient total synthesis of the phytotoxin porritoxin is described. The key step of the synthesis is based upon a Parham cyclization methodology which enables the creation of the lactam unit embedded in the title compound framework with the concomitant formation of the tethered hydroxyakyl chain.     

Structure of phaseolinone,a novel phytotoxin from macrophomina phaseolina

Structure of phaseolinone, a phytotoxin isolated from the fungus $\text{Macrophima phaseolina}$ (Tassi) Gold, has been established as $\text{1}$.