5α,11-二羟基-2-氧代桉烷-3-烯的全合成

5α，11-二羟基-2-氧代桉烷-3-(5α-Hydroxy—isopterocarpolone，1)是由贾忠建等于1996年从中药南牡蒿中首次分离得到的一种桉烷型倍半萜类天然产物．桉烷型倍半萜类化合物广泛分布于天然植物中，具有较好的昆虫拒食、抑制细胞繁殖和植物生长调节等多种生理活性．天然产物1的合成研究尚未见报道．     

7-表-γ-桉叶油醇的不对称全合成

桉烷型倍半萜类化合物广泛分布于自然界中, 普遍具有昆虫拒食、植物生长调节、细胞生长抑制等生物活性[1～3], 因此, 近年来越来越受到有机化学家的重视. 最近, 法国学者Ramanoelina等[4]从传统药用植物Laggera alata var. Alata Sch. Bip. Ex oliv.中分离得到的两个新的此类化合物: 7-表-γ-桉叶油醇(1)和7-表-β-桉叶油醇(2), 它们的合成均未见报道, 其结构如下式.     

3β-羟基-4,11-二烯桉烷酸甲酯的不对称全合成

近年来 ,从传统药用植物里分离出了很多桉烷酸类天然产物 ,它们绝大多数具有很好的杀菌、拒食等活性[1 ,2 ] .因此 ,对这一类天然产物的全合成研究成为当前的研究热点课题 .Ｓｃｈｅｍｅ 1　Ｔｈｅｓｔｒｕｃｔｕｒｅｏｆｃｏｍｐｏｕｎｄ 13β 羟基 4,1 1 二烯桉烷酸 (1 ,结构如Ｓｃｈｅｍｅ 1所示 )是德国化学家Ｂｏｈｌｍａｎｎ等[3] 从一种阿根廷的药用植物Ｓｔｅｖｉａａｃｈａｌｅｎｓｉｓ中分离得到的一个桉烷酸类天然产物 ,它的结构非常具有代表性 ,在反式十氢萘上共有 3个手性中心 ,其不对称全合成尚未见报道 .因此 ,如何高立体选…     

9-氧代桉烷-4-烯-3-酮类似物的DDQ脱氢重排反应机理研究

我们在研究 9-氧代桉烷 - 4-烯 - 3 -酮类化合物的 2 ,3 -二氯 - 5 ,6 -二腈基 - 1 ,4-苯醌 (DDQ)脱氢反应时[1] ,发现 1 4-降桉烷 - 4,1 1 -二烯 - 3 ,9-二酮及其 1 0 - Epimer在 DDQ脱氢条件下发生迁移重排反应 ,生成酚类化合物 .反应式如下 :DDQ脱氢反应已被详细研究 ,并被广泛地用于有机合成中 [2～ 5] ,但这种脱氢重排反应尚未见文献报道 .为了深入研究该反应 ,提出可能的重排机理 .我们参照文献 [6～ 1 0 ]方法 ,用 MVK和 EVK与相应的 2 -甲基 - 1 ,3 -二酮进行 Robinson成环反应 ,合成了一系列具有类似结构的化合物 ,并与 DD…     

桉烷-4(15)-烯-1β,7α-二醇的不对称全合成

天然产物桉烷-4(15)-烯-1β,7α-二醇(Y019)从植物中间锦鸡儿中分离得到,初步的药理活性研究中发现具有抗稻瘟霉活性.我们从原料1,3-环己二酮出发以线性步骤11步反应9.4%的总产率,首次完成了天然产物桉烷-4(15)-烯-1β,7α-二醇的不对称全合成,为进一步的药理活性研究奠定了基础.     

3,11(13)-二烯-12-桉烷酸的立体选择性全合成

桉烷型倍半萜类化合物广泛分布于天然植物中 ,此类化合物多具有较好的生理活性 ,其中桉烷酸类化合物因具有广泛的生物活性而受到重视 .例如 ,3,1 1 ( 1 3) -二烯 - 1 2 -桉烷酸 ( 1 )呈现较好的抗菌活性[1] ,桉烷酸 ( 2 )具有消炎退热的活性[2 ] . 3,1 1 ( 1 3) -二烯 - 1 2 -桉烷酸 ( 1 )是 Shtacher等 [1] 从地中海草药Inula viscosa Ait中分离得到的 .其合成工作尚未见文献报道 .化合物 ( 1 )和 ( 2 )的结构式见 Scheme1 .Scheme1　The structures of compouds1 and2首先以烯丙基氯化为关键反应 ,在桉烷骨架的 C- 1 2位上引入一个羟基…     

9-乙酰氧基乙基-6-烷氨基-2-烷硫基嘌呤的合成及抗血小板凝集活性评估

以2-氨基-6-氯嘌呤(1)为原料,与2-溴乙基乙酸酯反应得到9-乙酰氧基乙基-2-氨基-6-氯嘌呤(2);2经重氮-烷硫化得到9-乙酰氧基乙基-2-烷硫基-6-氯嘌呤(3);3经胺解反应得到14个未见报道的9-乙酰氧基乙基-6-烷氨基-2-烷硫基嘌呤化合物4.这些化合物的结构经IR,1H NMR,13C NMR及HRMS得到表征,同时进行了抗血小板凝集活性测试.     

12,6-桉烷内酯类天然产物的合成研究

综述了12,6-桉烷内酯类天然产物的化学合成方法.     

利用Pummerer反应合成2-(2,6-二卤苯基)-3-(4,5,6-三甲基-2-嘧啶基)-5-酯酰氧基-1,3-噻唑烷-4-酮衍生物

利用Pummerer反应,以有机酸为反应原料、溶剂和催化剂,简便、高效地合成了一系列2-(2,6-二卤苯基)-3-(4,5,6-三甲基-2-嘧啶基)-5-酯酰氧基-1,3-噻唑烷-4-酮(7a～7g和8a～8g),产率为62%～85%.X衍射确证化合物主要异构体的构型为噻唑烷-4-酮环C-5与C-2位取代基处于反式构型,顺反异构体比例通过1H NMR确定.化合物7a和8a具有中等强度的抗HIV-RT活性.     

无溶剂超声辐射下磷钨酸铈催化合成5-亚烃基-2,2-亚戊基-1,3-二噁烷-4,6-二酮

在CePW12O40催化下,芳香醛和2,2-亚戊基-1,3-二噁烷-4,6-二酮在无溶剂条件下经超声辐射合成了8种5-亚烃基-2,2-亚戊基-1,3-二噁烷-4,6-二酮.当催化剂的用量为5%(摩尔分数)时,室温反应20～35 min,收率为87.6%～94.1%.此外,还探讨了CePW12O40的可能催化机理.该方法具有条件温和,反应时间短且收率高的优点.催化剂CePW12O40对环境友好且可循环利用.     

First Total Synthesis of A New 5-Deoxyflavone

A novel 5-deoxyflavone compound, 7, 8-dimethoxy-3′, 4′-methylene-dioxyflavone (1), was in 2002 isolated from the root bark of Albizia Odoratissima. [1] The compound 1 was preparaed from pyrogallic acid (2) and piperonal(5) in four steps (Scheme 1). [2] The spectroscopic data (1H NMR, 13C NMR, MS and IR) of 1 were in good agreement with those of natural product. [ 1]     

1H and 13C NMR signal assignments of a novel Baeyer-Villiger originated diterpene lactone

A highly rearranged novel dilactone was the single product isolated from Baeyer-Villiger oxidation of a norketone prepared from grandiflorenic acid, a natural kaurane diterpene. The complete 1H and 13C NMR assignment is presented for this novel compound that showed discrete in vitro antibacterial activity.     

一种天然产物Wangzaozin A的细胞毒活性

从总序香茶菜Isodon racemosa (Hemsl) Hara植物中分离得到一个对人类肿瘤细胞Bel-7402和HD-8910具有毒活性的对映-贝壳衫烷型二萜Wangzaozin A化合物(1). 应用密度泛函理论(DFT)B3LYP方法, 对该分子的几何构型进行优化, 结果表明用B3LYP/6-31G(d)优化的几何参数与它的X射线衍射结构参数基本一致. 在优化的几何构型基础上, 采用规范不变原子轨道(GIAO)法, 在B3LYP理论水平分别用6-31G(d), 6-31G(d,p), 6-31+G(d,p)和6-31++G(d,p)基组进行核磁共振(NMR)化学位移值计算, 预测的1H和13CNMR化学位移值与实验值吻合; 统计误差分析表明, 用B3LYP/6-31G(d)优化的分子构型接近实际的分子构型. 因此, DFT方法适用这一类型化合物的构型和NMR参数进行预测. 在几何优化的基础上, 在B3LYP/6-31G(d)水平上, 对Wangzaozin A分子的静电位(MEP)进行理论计算. MEP三维图表明, 在Wangzaozin A分子中α-亚甲基环戊酮的羰基和羟基附近出现富电子区域(负电位), 起着供电子作用, 与受体的正电子区域结合. 这些结果从理论上支持了α-亚甲基环戊酮结构是一种抗肿瘤活性中心的看法.     

1H and 13C NMR assignments for two oxaphenalenones bacillosporin C and D from the mangrove endophytic fungus SBE-14

The complete (1)H and (13)C NMR assignments are reported for the novel natural product Bacillosporin D together with the known compound Bacillosporin C. These compounds containing seven rings were isolated from the mangrove endophytic fungus SBE-14 from the South China Sea. 1D and 2D NMR experiments, including COSY, HMQC and HMBC were used to the determination of the structures and NMR assignments. It is proposed that 1 was biogenetically produced by transforming 2. Transforming a lactone to an anhydride is unusual in nature.     

Two Eremophilane-type Sesquiterpenoids from the Rhizomes of Ligularia veitchiana（Hemsl.） Greenm

Two eremophilane-type sesquiterpenoids from the rhizomes of Ligularia veitchiana(Hemsl.) Greenm were isolated and determined as 10α,11-endoperoxide-1(2)-en-7α-hydroeremophilane(1) and 1(10)-en-2-oxo-7α-isopropanol-eremophilane(2).Compound 1 was a new compound and compound 2 was a new natural product.The structures of the two compounds were established by means of spectral methods including 1H NMR,13C NMR,2D NMR and MS.     

New bioactive natural products from Coprinus micaceus

Chemical studies on the crude methanolic extract of Coprinus micaceus, collected from the Canadian Prairie region, have resulted in the isolation of two new natural products, micaceol (1), a sterol and (Z,Z)-4-oxo-2,5-hetpadienedioic acid (2). Compound 2 was isolated for the first time as a natural product. Structures of these new compounds were established with the aid of extensive NMR spectroscopic studies. Compound 1 has shown anti-bacterial activity against Corynebacterium xerosis and Staphylococcus aureus, whereas compound 2 exhibited glutathione S-transferase inhibition.     

大萼香茶菜中的新二萜化合物

报道从大萼香茶菜叶的乙醇提取物中分离得到一种新的二萜类化合物, 并命名为大萼香茶菜癸素(1). 其药理活性实验结果证明, 该化合物对体外培养的Hela细胞有较强的抑制作用.     

新型瑞香酮类似物的合成及杀菌活性

以瑞香狼毒中分离的天然产物(E)-1,5-二苯基-2-烯-1-戊酮(A)为先导, 引入色酮片段设计合成了15个新型的瑞香酮类似物, 其结构均经IR, ¹H NMR, ¹³C NMR及元素分析或HRMS确证. 杀菌活性测试结果表明, 在100 mg/mL浓度下, 部分化合物的杀菌活性优于先导化合物A, 其中化合物6d对水稻纹枯病菌和黄瓜灰霉病菌的抑制率分别为87%和86%, 与对照药剂苯醚甲环唑相当, 值得进一步优化研究.     

Xylocarpins A and B, two new mexicanolides from the seeds of a Chinese mangrove Xylocarpus granatum: NMR investigation in mixture

Xylocarpins A and B, two new mexicanolides with a tiglate group at C-3, have been identified in the mixture using NMR spectroscopy. Both compounds were isolated in the mixture from the seeds of a Chinese mangrove Xylocarpus granatum. The first complete assignments of 1H and 13C NMR data for these mexicanolides were achieved by means of 2D NMR techniques, including 1H-1H COSY, HSQC, HMBC and NOESY spectra. In order to separate xylocarpins A (1) and B (2) by chemical method, the mixture of two compounds was reduced with sodium borohydride in anhydrous methanol. However, the reduction led to the opening of the delta-lactone ring in xylocarpin B and afforded compound 3 as the main product. The complete NMR assignments of compound 3 were also achieved by means of the above 2D NMR techniques. Moreover, xylocarpin A was easily transformed into xylocarpin B during our normal liquid column chromatography. From this point of view, xylocarpin A was deemed to be the genuine natural product and xylocarpin B might be an artifact.