On the synthesis and biological properties of isocombretastatins: a case of ketone homologation during Wittig reaction attempts

The syntheses of combretastatin A-4 from gallic acid and of three combretastatin-based hybrids are described. Starting from commercial gallic acid, the phosphonium salt (3,4,5-trimethoxybenzylphosphonium bromide) is synthesized and coupled, through a Wittig reaction, with several aldehydes, including methoxymethyl-protected isovanillin, the aldehyde γ-bicyclohomofarnesal having a labdane skeleton, 3-(3-pyridyl) propanal, and furfural. The biological properties of the cis-coupled compounds as cytotoxic, antiviral and antifungal agents are also reported. In addition, pyrogallol, gallic and 3,4,5-trimethoxybenzoic acids have been studied biologically.

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On the synthesis and the mechanism of formation of halogenated enol lactones

Canadian Journal of Chemistry ◽

10.1139/v97-158 ◽

1997 ◽

Vol 75 (10) ◽

pp. 1322-1330 ◽

Cited By ~ 5

Author(s):

Margaret M. Kayser ◽

Jun Zhu ◽

Donald L. Hooper

Keyword(s):

Reaction Mechanism ◽

Organic Synthesis ◽

Wittig Reaction ◽

Biological Properties ◽

Mechanism Of Formation ◽

Direct Route ◽

Cyclic Anhydrides ◽

Wittig Reactions

The synthesis of halo enol lactones from cyclic anhydrides via lactonization of the corresponding keto phosphoranes provides a direct route to these interesting compounds, which possess important biological properties and are useful intermediates in organic synthesis. In this paper we outline the syntheses of several halo enol lactones and discuss mechanistic consequences of these reactions on the understanding of Wittig reactions with cyclic anhydrides. Keywords: halolactonization, cyclic anhydrides, halo enol lactones, Wittig reaction mechanism.

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Chemical and biological properties of some oxindolidyl-3-methines

Canadian Journal of Chemistry ◽

10.1139/v68-357 ◽

1968 ◽

Vol 46 (13) ◽

pp. 2189-2194 ◽

Cited By ~ 7

Author(s):

R. Hodges ◽

J. S. Shannon ◽

W. D. Jamieson ◽

A. Taylor

Keyword(s):

Bacillus Subtilis ◽

Absorption Band ◽

Carbonyl Group ◽

Mass Spectrometer ◽

Wittig Reaction ◽

Biological Properties ◽

Residual Fragment ◽

Nitrofuran Derivatives

Several 1-methyloxindohdyl-3-methines have been synthesized, either by condensation of 1-methyloxindole with an aldehyde, or by a Wittig reaction of a chloromethylene compound with a 1-methylisatin When examined m the mass spectrometer the expected ion reactions were observed and, in addition, a reaction involving expulsion of the carbonyl group of the oxindole moiety and rearrangement of the residual fragment, to give a 1-methylbenzo[b]azepinium ion was observed. The anions of the oxindolidyluracilmethines 4 and 5, (R = Me, R′ = OH) had an absorption band near 380 mμ but the corresponding neutral molecules absorbed at 325–350 mμ. The 5-nitrofuran derivatives 3 were the only compounds that inhibited the growth of Bacillus subtilis.

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Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127608 ◽

1987 ◽

Vol 45 ◽

pp. 633-635

Author(s):

David A. Agard ◽

Yasushi Hiraoka ◽

John W. Sedat

Keyword(s):

Dimensional Space ◽

Three Dimensional ◽

Developmental State ◽

Mitotic Cell ◽

Biological Properties ◽

Dimensional Structure ◽

Specific Gene ◽

Three Dimensional Structure ◽

Complementary Techniques ◽

Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

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Membrane–cytoskeleton interactions in cholesterol-dependent domain formation

Essays in Biochemistry ◽

10.1042/bse0570177 ◽

2015 ◽

Vol 57 ◽

pp. 177-187 ◽

Cited By ~ 9

Author(s):

Jennifer N. Byrum ◽

William Rodgers

Keyword(s):

Biological Properties ◽

Membrane Rafts ◽

Membrane Domains ◽

Biological Functions ◽

Membrane Cytoskeleton ◽

Heterogeneous Structures ◽

Integral Role ◽

Model Cell ◽

Actomyosin Cytoskeleton ◽

Dependent Domain

Since the inception of the fluid mosaic model, cell membranes have come to be recognized as heterogeneous structures composed of discrete protein and lipid domains of various dimensions and biological functions. The structural and biological properties of membrane domains are represented by CDM (cholesterol-dependent membrane) domains, frequently referred to as membrane ‘rafts’. Biological functions attributed to CDMs include signal transduction. In T-cells, CDMs function in the regulation of the Src family kinase Lck (p56lck) by sequestering Lck from its activator CD45. Despite evidence of discrete CDM domains with specific functions, the mechanism by which they form and are maintained within a fluid and dynamic lipid bilayer is not completely understood. In the present chapter, we discuss recent advances showing that the actomyosin cytoskeleton has an integral role in the formation of CDM domains. Using Lck as a model, we also discuss recent findings regarding cytoskeleton-dependent CDM domain functions in protein regulation.

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