New long-chain tetrathiafulvalene derivatives with a diacetylene group
摘要:
The multi-stage synthesis of new long-chain tetrathiafulvalene derivatives containing a diacetylene group at different distances from tetrathiafulvalene moiety - 2-(tetracosa-9, 11-diynyle)-, 2-heptadeca-9, 11-diynyle)- and 2-(nonadeca-4,6-diynyle)-6,7-tetrathiafulvalene is described.
Tandem alkyne insertion and allyl sulfonium ylide rearrangement of γ,δ-alkynyl-α′-diazoketones
作者:Thomas R. Hoye、Christopher J. Dinsmore
DOI:10.1016/0040-4039(92)88041-3
日期:1992.1
catalytic rhodium carboxylate dimer and diallylsulfide (1.1 equiv), undergo sequential alkyneinsertion/ylide formation/sigmatropic rearrangement to give γ-allylthio cyclic enones. This transformation was used to probe the influence of alkyne substituents on 5-exo vs. 6-endo cyclization selectivity in the alkyneinsertion event.
Synthesis and Antitumor Activity of a Novel Series of 6-Substituted Pyrrolo[2,3-<i>d</i>]pyrimidine Thienoyl Antifolate Inhibitors of Purine Biosynthesis with Selectivity for High Affinity Folate Receptors and the Proton-Coupled Folate Transporter over the Reduced Folate Carrier for Cellular Entry
ituted pyrrolo[2,3-d]pyrimidines with a thienoyl side chain and four to six carbon bridge lengths (compounds 1−3) were synthesized as substrates for folatereceptors (FRs) and the proton-coupledfolatetransporter (PCFT). Conversion of acetylene carboxylic acids to α-bromomethylketones and condensation with 2,4-diamino-6-hydroxypyrimidine afforded the 6-substitutedpyrrolo[2,3-d]pyrimidines. Sonogashira
Novel Ag(I)-catalysis of an intramolecular 1,3-dipolar cycloaddition
作者:Andrew S. Kende、Michel Journet
DOI:10.1016/0040-4039(95)00470-w
日期:1995.5
Acetylenic α-diazoketones, bearing gem-dimethyl substituents in the α′ position, were found to undergo an intramolecular 1,3-dipolar cycloaddition reaction in the presence of silver(I) as catalyst. In that instance, bicyclic pyrazole derivatives were isolated in 47 to 55% yield, even in the conditions of the Arndt-Eistert reaction. The requirement for gem-dimethylsubstitution in acyclic substrates is rationalized
Modulating the development of E. coli biofilms with 2-aminoimidazoles
作者:Catherine S. Reed、Robert W. Huigens、Steven A. Rogers、Christian Melander
DOI:10.1016/j.bmcl.2010.08.075
日期:2010.11
The synthesis of a 20 member 2-aminoimidazole/triazole pilot library is reported. Each member of the library was screened for its ability to inhibit or promote biofilm development of either Escherichia coli and Acinetobacter baumannii. From this screen, E. coli-selective 2-aminoimidazoles were discovered, with the best inhibitor inhibiting biofilm development with an IC(50) of 13 mu M. The most potent promoter of E. coli biofilm formation promoted biofilm development by 321% at 400 mu M. (C) 2010 Elsevier Ltd. All rights reserved.
Oxazole activation for azomethine ylide trapping: singly and doubly tethered substrates
作者:Edwin Vedejs、David W. Piotrowski
DOI:10.1021/jo00058a010
日期:1993.3
Bicyclic oxazolium salts 18, 24, 37, and 44 can be generated from tethered haloalkyloxazoles by internal alkylation. Reductive alkylation of the oxazolium salts using CsF/PhSiH3 converts the salts initially into the corresponding 4-oxazoline derivatives. Subsequent electrocyclic ring opening generates stabilized azomethine ylides that can be trapped by suitable dipolarophiles. Intermolecular dipole trapping followed by DDQ oxidation affords the ring-fused pyrroles 22 and 26. When tethered alkynoates are used for internal dipole trapping, the adducts 38 and 45 can be obtained by a similar reductive activation sequence, followed by DDQ workup. Effective procedures for the internal oxazole N-alkylation step are described using an acetonitrile-trifluoroethanol solvent system. Also, an improved method for the generation of the dichlorocerium derivative of ethyl propiolate and intermolecular trapping by an aldehyde is reported.