齐墩果酸的结构修饰和α-葡萄糖苷酶抑制活性

以天然五环三萜类化合物齐墩果酸为原料, 通过氧化、酯化、环合和曼尼希等反应, 对A环2, 3位和28位进行结构修饰, 设计合成了16个衍生物; 通过理化性质、质谱和核磁数据确定了化合物结构. 对合成的衍生物进行了体外α-葡萄糖苷酶抑制活性筛选, 结果表明, 受试化合物在200 μg/mL浓度下显示出不同程度的酶抑制活性. 初步构效关系分析表明, 28位游离羧基是活性必需基团, 3位羟基或相应的氢键供体取代基有利于提高活性.     

Synthesis and Anti-tumor Activity of Novel Glycyrrhetinic Acid Derivatives

Twenty-five derivatives of glycyrrhetinic acid(GA)modified on the A-ring,at C30 and C11 positions were synthesized.Their in vitro cytotoxicity against various cancer cell lines[henrietta lacks strain o...     

Synthesis of 14-deoxy-benzylidene-8,17-epoxy-diene-andrographolide derivatives and evaluation of their anticancer activities

Synthesis of 14-deoxy-benzylidene-8,17-epoxy-diene-andrographolide derivatives from andrographolide and evaluation of their anticancer activities were described herein. 3,19 hydroxy groups of andrographolide were protected by benzylidene which undergo m-chloroperbenzoic acid mediated epoxydation in moderate yield to form corresponding epoxy derivatives. Thereafter mild basic condition was applied to perform de-hydroxylation at C-14 which resulted in conjugated diene derivatives of benzylidene epoxy andrographolide. These compounds were examined against different human cancer cell lines and were found to inhibit their proliferation at IC₅₀ in the range of 3–20 μM in order to elucidated the role of allylic hydroxyl group at C-14.     

槲皮素-3-O-丙基衍生物的合成及生物活性研究

槲皮素是具有丰富生物活性的黄酮类化合物,药理活性显著。本文以槲皮素为先导物,选择性对C环3位羟基进行修饰,以廉价的芦丁为原料,经苄基保护、Williamson成醚反应,再经Pd/C催化加氢脱苄基得到28个未见文献报道的槲皮素-3-O-丙基衍生物,其结构经¹H NMR、¹³C NMR、ESI-MS进行确证。采用MTT法考察了所合成化合物对人食管鳞癌（EC109）、人胃癌（HGC27）、人乳腺癌（MCF-7）、小鼠黑色素瘤（B16-F10）的增殖抑制作用。结果显示,通过化学方法对槲皮素结构进行修饰后,其体外抗肿瘤活性增强。其中,化合物F3(IC₅₀=5.23±0.37μmol/L)、F5(IC₅₀=2.63±0.09μmol/L)对小鼠黑色素瘤（B16-F10）抑制作用比5-氟尿嘧啶(IC₅₀=14.38±0.27μmol/L)好,值得进一步研究。     

Antiallergic Activity of 6-Deoxy-2-O-methyl-6-(N-hexadecanoyl)amino-l-ascorbic Acid

Allergy is an excessive immune response to a specific antigen. Type I allergies, such as hay fever and food allergies, have increased significantly in recent years and have become a worldwide problem. We previously reported that an ascorbic acid derivative having palmitoyl and glucosyl groups, 2-O-α-d-glucopyranosyl-6-O-hexadecanoyl-l-ascorbic acid (6-sPalm-AA-2G), showed inhibitory effects on degranulation in vitro and on the passive cutaneous anaphylaxis (PCA) reaction in mice. In this study, several palmitoyl derivatives of ascorbic acid were synthesized and a structure–activity relationship study was performed to discover more potent ascorbic acid derivatives with degranulation inhibitory activity. 6-Deoxy-2-O-methyl-6-(N-hexadecanoyl)amino-l-ascorbic acid (2-Me-6-N-Palm-AA), in which a methyl group was introduced into the hydroxyl group at the C-2 position of ascorbic acid and in which the hydroxyl group at the C-6 position was substituted with an N-palmitoyl group, exhibited much higher inhibitory activity for degranulation in vitro than did 6-sPalm-AA-2G. 2-Me-6-N-Palm-AA strongly inhibit the PCA reaction in mice at lower doses than those of 6-sPalm-AA-2G. These findings suggest that 2-Me-6-N-Palm-AA may be a promising therapeutic candidate for allergic diseases.     

Experimental and Molecular Mechanical Studies of Complexation of Some 2H- and 3H- Indole Derivatives with Aqueous β-Cyclodextrin

Phase solubility diagrams (PSDs) at 25 ^∘C and molecular mechanical (MM) modeling were used to study the aqueous complexation of some 2H- and 3H-indole derivatives with β-cyclodextrin (β-CD). Among the 3H-indole derivatives investigated in this work, indole-3H-butyric acid forms the most stable 1:1 complex of the B _s -type PSD, whereas shorter chain derivatives form soluble 1:1 complexes (A _L -type PSDs) with their stability increasing as the chain length increases. Indole-2 carboxylic acid forms highly stable 1:1 and 1:2 complexes, with the lower-order complex reaching saturation first (B _s -type PSD). MM modeling indicates that the stability of the complex is highly correlated with the flexibility of the 3H-indole hydrocarbon chain, which yields a better geometrical fit within the β-CD cavity resulting from different hydrophilic interactions. These interactions are represented in the H-bonding of the carboxyl group with the primary hydroxyl group network that is situated at the narrow rim of the cavity, and also by a favorable interaction of the aromatic ring with the hydroxyl group network at the other rim.     

Pseudoprolines (psiPro) in drug design: direct insertion of psiPro systems into cyclosporin C

The insertion of acetals that exhibit variable structural features into complex peptides such as cyclosporin C (CsC) results in oxazolidine derivatives (pseudoprolines, psiPro) of tailored physico-chemical and biological properties. N,O-Acetalation of the 2-threonine hydroxyl group and the preceding amide nitrogen of CsC is achieved by treating the molecule with a number of both arylated and non-arylated dimethyl acetals. The psiPro-containing CsC derivatives exhibit enhanced conformational backbone rigidity, as suggested by analytical HPLC, NMR spectroscopy and by kinetic measurements on binding with their receptor protein cyclophilin A (CypA) that were not time-dependent. IC50 values for calf-thymus CypA were obtained by kinetic evaluation of its cis-->trans isomerase activity. The choice of the para-substituted aryl dimethyl acetals allows the inhibitory properties of the corresponding derivatives to be modulated to either prodrugs or moderately strongly binding cyclosporin C derivatives.     

Oxidation of 5-hydroxy-2'-deoxyuridine into isodialuric acid, dialuric acid, and hydantoin products

Oxidation products of cytosine, including 5-hydroxycytosine and 5-hydroxyuracil, are highly susceptible to subsequent oxidation. Here, the oxidation products of 5-hydroxy-2'-deoxyuridine have been studied by NMR and MS analyses. The initial products were diastereomers of isodialuric acid nucleoside. These products subsequently decomposed into corresponding dialuric acid derivatives at neutral pH. The position of the carbonyl and hydroxyl groups, at C5 and C6 for isodialuric acid and at C6 and C5 for dialuric acid derivatives, respectively, was determined by 1H- and 13C NMR analyses. In addition, these analyses revealed that the carbonyl groups of both isodaluric and dialuric acid derivatives exist in their fully hydrated form in aqueous solution. Finally, the dialuric acid derivatives were observed to undergo subsequent decomposition into the corresponding 5-hydroxyhydantoin derivatives. Studies of a trinucleotide containing 5-hydroxyuracil suggest that the reactions described herein for the monomer can be extrapolated to DNA.     

Design,synthesis characterization and in vitro biological activity of a series of 3-aryl-6-(bromoarylmethyl)-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives as the novel acetylcholinesterase inhibitors

Bromination is used as a strategy to improve biological activity in medicinal chemistry.In order to study on the structure-activity relationships of the novel acetylcholinesterase inhibitors with 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one scaffold,based on our previous work and molecular modeling,a series of novel 3-aryl-6-(bromoarylrnethyl)-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were designed by molecular docking,synthesized and characterized by mass spectra,infrared spectra,proton NMR and elemental analyses.The study of AChE inhibitory activity was carried out using the Ellman colorimetric assay with huperzine-A as the positive control.Most of all target compounds exhibited more than 45%inhibition at 10μmol/L.The preliminary structureactivity relationship was the bromine atoms and the hydroxyl group at the phenyl ring at the C6 position of the parent nucleus played significant roles in the AChE inhibitory activity of the target compounds.     

新型齐墩果酸糖苷化衍生物的合成及体外抗HCT8活性

为提高齐墩果酸的水溶性和稳定性,以齐墩果酸苷元为起始原料,对其28-COOH进行甲基化修饰后制得齐墩果酸-28-羧甲酯(1)。分别以D-半乳糖、D-葡萄糖、D-氨基葡萄糖为起始原料,通过对糖羟基的保护与去保护,得到一系列的二糖、四糖片段。通过三氯乙酰亚胺酸酯途径和对甲苯硫基途径,利用合成的糖片段对1的3-位羟基进行糖化学结构修饰,合成了4种新型的齐墩果酸糖苷化衍生物(2~5),其结构经1H NMR,13C NMR和MS(ESI)表征。采用MTT法测试了2~5对高表达人结肠癌细胞(HCT8)的体外抑制活性。结果表明:2~5对HCT8有一定的抑制作用,化合物5浓度为1×10^-3 mmol/L时,抑制率达到(98.96±0.10)%。     

熊果酸衍生物的合成、表征及其对癌细胞的抑制活性

以熊果酸为母体化合物,对其3-OH和17-COOH进行结构修饰,设计合成了9个熊果酸衍生物,其结构经IR、¹H NMR和MS测试技术确证;噻唑蓝(MTT)比色法考察了所合成衍生物对体外人肝癌细胞HepG2培养增殖的抑制作用,结果显示受试衍生物均对细胞增殖有一定抑制作用,且呈剂量依赖性,其中衍生物9的抑制作用最强;衍生物9与细胞作用24 h后,经Hoechst 33342/PI双染色,倒置荧光显微镜下观察,出现细胞凋亡所具有的高蓝色/低红色荧光图;流式细胞术检测细胞周期发现：细胞被阻滞于S期,且阻滞作用随药物浓度的增加而增强。     

Eremophilane sesquiterpenes from capsidiol

A series of eremophilane sesquiterpene alcohols and hydrocarbons was prepared from the phytoalexin capsidiol (1) for mechanistic studies with epiaristolochene synthase and epiaristolochene dihydroxylase. Among them, 3-deoxycapsidiol (10) was obtained through selective derivatization and reductive cleavage of the equatorial 3 alpha hydroxyl group. Two novel isomers of aristolochene and eremophilene were accessed from the 1- and 3-deoxycapsidiol isomers. 4-Epieremophilene (17) was obtained by conjugate reduction of epiaristolochen-1-one tosylhydrazone with catecholborane followed by sulfinate elimination and diimide rearrangement. Epimerization of epiaristolochen-3-one (27a) at the C4 methyl followed by reductions led to the previously unknown aristolochene isomer, eremophila-9(10),11(12)-diene (30). Optical rotations and characteristic (1)H NMR data for the related eremophilenols and dienes are collected in Tables 1 and 2. Finally, bioassays were used to assess the antifungal potencies of capsidiol and its synthetic derivatives. The minimum inhibitory concentration for capsidiol (3-10 ng) was at least 1 order of magnitude lower than that of any of the derivatives and considerably lower than those previously reported for ketoconazole, nystatin, and propiconazole.     

Microwave-assisted synthesis and biological evaluation of new thiazolylhydrazone derivatives as tyrosinase inhibitors and antioxidants

In this work, we have synthesized a series of 2-thiazolylhydrazone derivatives ( 1–27 ) and investigated their biological activities as tyrosinase inhibitors and antioxidants. Some compounds showed potent tyrosinase inhibitory activities and 4-(2-(2-(1-(4-Aminophenyl)ethylidene)-hydrazinyl)thiazol-4-yl) phenol ( 26 ) showed more potent inhibitory effect than the standard tyrosinase inhibitor kojic acid (IC₅₀: 9.8 μM vs. 23.6 μM). Compounds 2 , 14 , and 26 exhibited high antioxidant activities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The structure–activity relationship (SAR) indicated that the substitutions of bromine, hydroxyl group, and amino groups cause great effect to the inhibition effect against tyrosinase. The mechanism and kinetic studies demonstrated that the inhibitory effect of compound 26 on the tyrosinase by acting as the reversible and uncompetitive inhibitor. Docking studies suggests that compound 26 interacts strongly with mushroom tyrosinase via hydrogen bonding.     

Investigation of the Effect of Four Organic Acids in Radix Isatidis on E. coli Growth by Microcalorimetry

The inhibitory effects of four organic acids (OAs) in Radix Isatidis, a traditional Chinese medicinal herb, on Escherichia coli (E. coli) growth were investigated by microcalorimetry. The power‐time curves of E. coli growth with and without OAs were acquired, meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k₁, k₂), half inhibitory ratio (IC₅₀), maximum heat output (P_max) and peak time (t_p). The values of k₁ and k₂ of E. coli growth in the presence of the four OAs decreased with the increasing concentrations of OAs. Moreover, P_max was reduced and the value of t_p increased with increasing concentrations of the four drugs. The sequence of anti‐microbial activity of the four OAs was: syringic acid>2‐amino‐benzoic acid>salicylic acid>benzoic acid. IC₅₀ of the four OAs was respectively 56 µg/mL for syringic acid, 75 µg/mL for 2‐amino‐benzoic acid, 86 µg/mL for salicylic acid and 224 µg/mL for benzoic acid. The existence of the functional groups on phenyl ring improves the anti‐microbial activity compared to benzoic acid. The functional groups methoxyl at C(3) and C(5) improve anti‐microbial activity more strongly than the other functional groups, and the functional group amino at C(2) improve anti‐microbial activity more strongly than hydroxyl at C(2) on phenyl ring.     

对苯二酚的氨基酸缀合物的合成、表征及美白活性

以新药设计原理中的拼合原理为指导,将对苯二酚一侧酚羟基与具有生物活性的氨基酸进行偶联,以期得到活性更好、毒性更低的对苯二酚氨基酸缀合物。 将对苯二酚的一侧酚羟基进行保护得到对苄氧基苯酚,将氨基被保护的氨基酸与其酚羟基进行偶联,去掉保护基后得到8种对苯二酚的氨基酸缀合物。 在对苄氧基苯酚的酚羟基上引入乙酸连接片段,与氨基酸甲酯盐酸盐进行偶联,去掉保护基后得到8种对苯二酚的氨基酸缀合物。 通过IR、¹H NMR、¹³C NMR和ESI-MS等技术手段对所合成的16种氨基酸缀合物进行了结构表征。 对目标产物进行了美白活性研究。 结果表明,化合物HQ-3b、HQ-3c、HQ-4a、HQ-4b、HQ-7c和HQ-8a对酪氨酸酶的抑制作用优于阳性对照物α-熊果苷(IC₅₀=3.60),其中HQ-4b的IC₅₀值低至0.15,有望成为新型化妆品美白剂。     

Antineoplastic agents 491. Synthetic conversion of aaptamine to isoaaptamine, 9-demethylaaptamine, and 4-methylaaptamine

Aaptamine (1) was used as starting material for synthetic transformation to isoaaptamine (2), 9-demethylaaptamine (5), and 4-methylaaptamine (6). A general method for the selective O-demethylation of such 1H-benzo[de][1,6]-naphthyridine (1) marine sponge constituents at position C-9 has been developed. Selective O-demethylation of aaptamine (1) and 1-methylaaptamine (11) with 48% hydrobromic acid led to 9-demethylaaptamine (5) and isoaaptamine (2), respectively. A selection of other aaptamine derivatives were synthesized, and their structures were unambiguously determined by X-ray methods. In addition, their cancer cell growth inhibitory properties were evaluated against the murine P388 lymphocytic cell line and a minipanel of human cancer cell lines. Evaluation as inhibitors of the PKC signal transduction pathway and against a selection of microorganisms was also undertaken. Aaptamine derivatives 3 and 5 had broad-spectrum antimicrobial activities.     

Phosphorylated cellulose propionate derivatives as thermoplastic flame resistant/retardant materials: influence of regioselective phosphorylation on their thermal degradation behaviour

Cellulose ester derivatives having phosphoryl side-chains were synthesized by phosphorylation of two types of cellulose propionate (CP); the difference between the two CPs was whether the primary hydroxyl group at C6 had been fully propionylated or not. Dimethyl phosphate, dimethyl thiophosphate, diethyl phosphate, or diethyl thiophosphate was introduced into the residual hydroxyl positions of the CPs. Chemical composition of the respective derivatives was characterized by elemental analysis and a combined use of saponification and HPLC quantification of the released propionic acid. Their thermal properties were investigated by DSC and TGA, and an intermediate residue of the pyrolysis was also examined by FT-IR spectroscopy. From the thermal degradation measurements using TGA, the C6-O phosphorylation was found to noticeably prevent the CP derivatives from weight loss in the pyrolysis process under dynamic air, i.e., providing them with a flame-resistance functionality, whereas the C2-O and C3-O phosphorylation did not give rise to such an appreciable resistance effect. A discussion was focused on the difference in pyrolysis mechanism between the phosphorylated CPs. However, most samples of the CP derivatives showed a clear T _g considerably lower than the onset temperature of the thermal degradation. Thus we suggest that it is possible to design thermoplastic flame resistant/retardant materials based on cellulose, by controlling the substitution distribution of the phosphoryl and propionyl groups introduced.     

新型2-芳氨基嘧啶衍生物的合成

通过间羟基苯硼酸与2,4-二氯嘧啶的Suzuki反应及其后酚羟基的烷基化得到4-芳基-2-氯嘧啶衍生物. 然后, 采用Pd(PPh3)4/dppf催化剂, 在温和的条件下实现了4-芳基-2-氯嘧啶类化合物和芳香胺的偶联. 合成了3个结构新颖的2-芳氨基嘧啶类化合物. 中间体及产物的结构均经由IR, 1H NMR, 13C NMR, MS和元素分析表征而予以证实.     

Potential bile acid metabolites. 25. Synthesis and chemical properties of stereoisomeric 3alpha,7alpha,16- and 3alpha,7alpha,15-trihydroxy-5beta-cholan-24-oic acids

Epimeric 3alpha,7alpha,16- and 3alpha,7alpha,15-trihydroxy-5beta-cholan-24-oic acids and some related compounds were synthesized from chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA), respectively. The key reaction involved one-step remote oxyfunctionalization of unactivated methine carbons at C-17 of CDCA and at C-14 of UDCA as their methyl ester-peracetate derivatives with dimethyldioxirane (DMDO). After dehydration of the resulting 17alpha- and 14alpha-hydroxy derivatives with POCl(3) or conc. H(2)SO(4), the respective Delta(16)- and Delta(14)-unsaturated products were subjected to hydration via hydroboration followed by oxidation to yield the 3,7,16- and 3,7,15-triketones, respectively. Stereoselective reduction of the respective triketones with tert-butylamine-borane complex afforded the epimeric 3alpha,7alpha,16- or 3alpha,7alpha,15-trihydroxy derivatives exclusively. A facile formation of the corresponding epsilon-lactones between the side chain carboxyl group at C-24 and the 16alpha- (or 16beta-) hydroxyl group in bile acids is also clarified.