Synthesis of new 7-aminosterol squalamine analogues with high antimicrobial activities through a stereoselective titanium reductive amination reaction

A series of 7-amino- and polyaminosterol analogues of squalamine and trodusquemine were synthesized involving a new stereoselective titanium reductive amination reaction in high chemical yields of up to 95% in numerous cases. These derivatives were evaluated for their in vitro antimicrobial properties against human pathogens. All the compounds present excellent activities against Gram-positive bacteria exhibiting similar results against Staphylococcus aureus and Streptococcus faecalis with minimum inhibitory concentrations (MICs) varying from 2.5 to 10 μg/mL. Numerous derivatives possess also MICs against Gram-negative Escherichia coli bacteria (MICs varying from 2.5 to 10 μg/mL) suggesting that nature of the amino group attached to the sterol moiety plays an important role on the activities of such products.     

SINGLE MACHINE SCHEDULING WITH CONTROLLABLE PROCESSING TIMES AND COMPRESSION COSTS （PART I：EQUAL TIMES AND COSTS）

Most papers in scheduling research have treated individual job processing times as fixed parameters. However, in many practical situations, a manager may control processing time by realloeating resources. In this paper, authors consider a machine scheduling problemwith controllable processing times. In the first part of this paper, a special case where the pro-cessing times and compression costs are uniform among jobs is discussed. Theoretical results are derived that aid in developing an O（n^2) algorithm to slove the problem optimally. In the second part of this paper, authors generalize the discussion to general case, An effective heuristic to the genera/ problem will be presented.     

2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑的合成

通过对称双酰肼与P_2S_5的缩合反应合成2,5-二-羟苯基-1,3,4-噻二唑,并由此制备了2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑及其相关化合物,同时测定了它们的生物活性。     

α-(1H-1,2,4-三唑-1-基)-β-芳硫基取代苯酮的合成及生物活性研究

利用 2 (1H 1,2 ,4 三唑 1 基 ) 2 丙烯 1 酮 (2 )与取代硫酚或含巯基的杂环化合物进行 1,4 亲核加成 ,得到目标化合物 3,其结构经元素分析、核磁和红外光谱所证实 ,并对其进行了生物活性的测试 ,发现大部分化合物具有很好的抑菌活性 .结构与活性的关系表明不同的R1取代对其生物活性有较大的影响 ,当R1=(CH3 ) 3 C时 ,对小麦锈病的抑制活性要高于R1=Ar的活性 ,而Ar上不同的取代基对其活性影响不大     

New pyranosyl cembranoid diterpenes from Sarcophyton trocheliophorum

During our continual searching programme for novel bioactive metabolites from Sarcophyton trocheliophorum, collected from Red Sea, we describe herein the isolation and structural elucidation of further two new pyrane-based cembranoid diterpenes: 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and 8,9-expoy-sarcotrocheliol acetate (2), along with the well-known sarcotrocheliol acetate (3), (+)-sarcophine (4), (+)-sarcophytoxide (5) and (-)-sarcophytoxide (6). The chemical structures of compounds 1 and 2 were determined on the basis of 1D and 2D NMR (¹H, ¹³C, ¹H–¹H COSY, HMQC, HMBC and NOE), mass spectra (ESI and HR-ESIMS) and by comparison with related structures. The antimicrobial activities of the reported compounds 1–6 were investigated. According to the molecular docking study of compounds 1–6 using 3D structure of α,β tubulin in complex with taxol (PDB code 1JFF) and epothilone A (PDB code 1TVK), sarcophine (4) displayed the highest affinity towards both crystal structures, followed by 5 and 6, meanwhile pyrane-based cembranoid diterpenes (1–3) showed less affinity.     

Biologisch aktive 3,3-Dimethylbicyclo[2.2.2]octane: Synthesen in der Isocamphanreihe, 35. Mitt.

Summary The bicyclo[2.2.1]- and [2.2.2]-systems are part of numerous biological active substances. Continuing our syntheses in the isocamphane series the homologous isocamphanes of mecamylamine (1 a) and of the fungicidal bicyclic compound2 were synthesized. Furthermore the syntheses ofE-homoisosantalene (15) andE,E-homoisosantalol (16) are described.

     

2,4,6—三氧—1,3,5,2—三氮磷杂环己烷衍生物的合成及其抗肿瘤活性

利用Ｎ，Ｎ－二（２－氯乙基）氨基磷酰二异氰酸酯和胺的加成反应，合成了２，４，６三氧－１，３，５，２三氮磷杂环己烷衍生物，它们的结构经＾１ＨＮＭＲ，ＩＲ和元素分析所证实。初步生物活性测试结果表明，部分化合物具有一定的抗肿瘤活性。     

Neosappanone A, a xanthine oxidase (XO) inhibitory dimeric methanodibenzoxocinone with a new carbon skeleton from Caesalpinia sappan

A novel dimeric methanodibenzoxocinone, named neosappanone A (1), possessing a unique unprecedented novel carbon framework, has been isolated from the heartwood of Caesalpinia sappan L. of Vietnam, and its structure was elucidated on the basis of spectroscopic analysis. Neosappanone A (1) competitively inhibited xanthine oxidase in a concentration-dependent manner (IC₅₀, 29.7 μM; K_i, 16.3 μM).     

Structure—activity relationships for <Emphasis Type="Italic">in vitro</Emphasis> oxime reactivation of chlorpyrifos-inhibited acetylcholinesterase

Organophosphorus pesticides parathion, chlorpyrifos, and malathion inhibit the enzyme acetylcholinesterase (AChE; EC 3.1.1.7) via phosphorylation of its active site. AChE reactivators and anticholinergics are compounds used as antidotes in the case of intoxication by these AChE inhibitors. In this work, chlorpyrifos, a representative member of this pesticide family, was used to inhibit the AChE activity of rat brain. The effect of twenty-one structurally different AChE reactivators was tested in vitro and subsequently, the relationship between their chemical structure and biological activity was outlined.