南蛇藤倍半萜成分研究

从南蛇藤(Celastrus gemmatus)的根皮中分得两个新的倍半萜化合物(1和2), 经高场核磁和高分辨质谱分析, 推定1为1β, 6α, 8β-三乙酰氧基-2β, 12-二异丁酰氧基-9α-(β-呋喃甲酰氧基)-4α-羟基-β-二氢沉各呋喃, 2为1β, 8α-二乙酰氧基-2β,12-二异丁酰氧基-9β-苯甲酰氧基-4α, 6α-二羟基β-二氢沉香呋喃。     

南蛇藤倍半萜成分研究

从南蛇藤(Celastrus angulatus)的种子中分得三个新的倍半萜化合物(1～3)。它们的结构经紫外、红外、质谱及二维核磁谱确定为1β-乙酰氧基-8α-苯甲酰氧基-9β, 13-二(β-吡啶甲酰氧基)-β-二氢沉香呋喃(1)-1β, 2β-二羟基-6α-乙酰氧基-8β, 9β-二苯甲酰氧基-β-二氢沉香呋喃(2)和1β, 2β, 8β, 9β-四苯甲酰氧基-6α-乙酰氧基-β-二氢沉香呋喃(3)。     

黑紫橐吾化学成分的分离与鉴定

利用各种色谱技术对黑紫橐吾的乙酸乙酯萃取部位进行分离纯化, 并且根据一维和二维波谱数据进行结构鉴定. 共分离得到4个呋喃雅槛蓝型倍半萜: 1α-氯-6β-异丁酰基-9-酮-10β-羟基-呋喃雅槛蓝烷(1), 1α-羟基-6β-异丁酰基-9-酮-10β-氢-呋喃雅槛蓝烷(2), 1α-羟基-6β-异丁酰基-9-酮-10α-氢-呋喃雅槛蓝烷(3)和1α,10β-二羟基-6β-当归酰基-9-酮-呋喃雅槛蓝烷(4). 其中化合物1为新化合物, 并且通过X射线单晶衍射确定了绝对构型; 化合物2~4为首次从该植物中分离得到.     

6-烷氨基-2-乙硫基嘌呤核苷化合物的合成及抗血小板聚集活性研究

以鸟苷(1)为原料,与乙酸酐经过糖环羟基保护反应,得到2',3',5'-三-O-乙酰基鸟苷(2);2与对甲苯磺酰氯反应,得到9-(2',3',5'-三-O-乙酰基-β-D-呋喃核糖)-2-氨基-6-对甲苯磺酰氧基嘌呤(3);3与亚硝酸异戊酯和二乙基二硫醚反应,得到9-(2',3',5'-三-O-乙酰基-β-D-呋喃核糖)-6-对甲苯磺酰氧基-2-乙硫基嘌呤(4);4经过胺解和脱糖环羟基保护反应得到10个未见报道的6-烷氨基-2-乙硫基嘌呤核苷化合物(5).化合物结构经1H NMR、13C NMR、IR和HRMS进行了表征,并对它们进行了抗血小板聚集活性测试,结果表明对抗血小板聚集显示一定的活性.     

自制氢化松香主要化学组成的GC-MS法测定

利用自行改进的DEAE－Sephadex离子交换色谱从以玉米松香为原料制备的氢化松香中分离出主要化学组成部分－酸性部分，然后采用DB－5毛细管柱和GC－MS技术对酸性部分进行定性和相对含量测定；共鉴定出6种二氢枞酸型树脂酸，4种二氢海松酸／异海松酸型树脂酸，1种四氢枞酸型树脂酸，2种四氢海松酸／异海松酸型树脂酸；其主要成分为13－二氢枞酸、8－二氢枞酸、13β－7－二氢枞酸、8α，13β－四氢枞酸及8（14）－二氢海松酸等。     

3-羟基氧杂环丁烷的合成及其对甲苯磺酸酯与碘化钠的交换

以两条不同路线合成了3-苄氧基氧杂环丁烷(4).2-O-苄基甘油(2)分步酰化为1-O-对甲苯磺酰-3-O-苯甲酰-2-O-苄基甘油(3)后,在甲醇钠作用下环化为4,总产率约30％.另一途径包括烯丙醇与苄醇在氢氧化钠存在下通氯气加成为3-氯-2-苄氧基丙醇(8),继以氢氧化钠环化为4,总产率13％.4经催化氢解生成3-羟基氧杂环丁烷(1).1的对甲苯磺酸酯(9)在沸丁酮中与碘化钠的交换甚至比1,3-二-O-甲基甘油对甲苯磺酸酯(10)还慢,可能是环氧原子的吸电子诱导效应和场效应的综合结果.     

新型芳基修饰的尿苷型荧光探针的合成及其性能

4-氟苯乙酮经二氧化硒氧化得到4-氟苯甲酰甲酸(1);1与盐酸氨基脲在碱性条件下经环合反应制得5-(4-氟苯基)-6-氮杂嘧啶(2);2与1-乙酰氧基-2,3,5-三苯甲酰氧基-1-β-D-呋喃核糖在无水乙腈中反应得2',3',5'-三苯甲酰氧基-5-(4-氟苯基)-6-氮杂尿苷(3);3在甲醇中水解合成了一种新型荧光核苷探针——5-(4-氟苯基)-6-氮杂尿苷(4),其结构经1H NMR,13C NMR和MS(ESI)表征。并研究了4的性能。结果表明:4在水中的量子产率高达0.81,对极性变化敏感;4可选择性识别Pd2+,在5.0×10-7~5.0×10-6mol·L-1能定量检测Pd2+。     

南鹤虱中两个新的倍半萜类化合物（英文）

从中药南鹤虱(Fructus carotae)中分离纯化得到7个倍半萜类化合物,分别鉴定为7-ethoxy-4(15)-oppositen-1β-ol(1),11-乙酰氧基-8β-当归酰氧基-15-甲氧基-4α,5α-环氧愈创木烷-3-酮(2),11-乙酰氧基-8β-丙酰氧基-4-愈创木烯-3-酮(3),1-oxo-5α,7αH-eudesma-3-en-15-al(4),1β-hydroxy-4(15),7-eudesmadiene(5),1β-hydroxy-4(15),5E,10(14)-germacratriene(6),1β-hydroxy-4(15),5-eudesmadiene(7).其中化合物1和2为新的化合物,新化合物的结构进一步通过HR-ESIMS,1D NMR和2D NMR等光谱技术确定.     

萘并呋喃类化合物的染料化光氧化及其杂环衍生物的合成与表征

萘并呋喃类化合物1、7在四苯基卟啉存在与氧低温反应给出相应的二氧杂环丁烷类产物2、8，室温下分别全部分解成乙酰基乙酰氧基化合物4、9。2和盐酸作用可给出呋喃3-位甲基及所在萘半环β位的二氯代产物6。4与盐酸反应通过失去萘α位的酰基，形成羟基呋喃化合物3，1在三溴化硼酸解下亦可得同一产物。4在醋酸钠/酸酐中环构生成3-乙酰基吡喃酮(5)。     

多羟基取代二氢沉香呋喃倍半萜的合成方法

二氢沉香呋喃倍半萜是一类具有杀虫、抑菌等多种活性的天然化合物.由于重要的生物活性和结构的复杂性,从而吸引了有机合成化学家的关注.最近,我们小组从桉烷倍半萜α-(-)-山道年出发,经过NBS促进的四氢呋喃环成环、OsO4双羟基化、环氧化合物的碱重排等一系列官能团转化,合成了七羟基取代的二氢沉香呋喃倍半萜化合物1,进而开拓了一种新颖、简洁的合成多羟基取代二氢沉香呋喃倍半萜的方法,其合成路线如下所示.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.