83758-93-4Relevant academic research and scientific papers
Sonogashira reaction of aryl halides with propiolaldehyde diethyl acetal catalyzed by a tetraphosphine/palladium complex
Lemhadri, Mhamed,Doucet, Henri,Santelli, Maurice
, p. 9839 - 9847 (2007/10/03)
All-cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/[PdCl(C 3H5)]2 efficiently catalyzes the Sonogashira reaction of propiolaldehyde diethyl acetal with a variety of aryl bromides and chlorides. A minor electronic effect of the substituents of the aryl bromide was observed. Similar reaction rates were observed in the presence of activated aryl bromides such as 4-trifluoromethylbromobenzene and deactivated aryl bromides such as bromoanisole. Turnover numbers up to 95,000 can be obtained for this reaction. Even aryl chlorides and heteroarylbromides or chlorides have been successfully alkynylated with this catalyst. Moreover, a wide variety of substituents on the aryl halide such as fluoro, trifluoromethyl, acetyl, benzoyl, formyl, nitro, dimethylamino or nitrile are tolerated.
Synthesis and non-linear properties of disubstituted diphenylacetylene and related compounds
Kondo, Koichi,Fujitani, Takumi,Ohnishi, Noriaki
, p. 429 - 433 (2007/10/03)
A variety of disubstituted diphenylacetylenes and related compounds have been synthesized by a modified Horner-Emmons reaction, and their second harmonic generation (SHG) has been evaluated by the Kurtz powder method. The diphenylacetylenes with weak electron-donating and -withdrawing groups are found to be efficient for SHG, as well as having the lowest cut-off wavelength.
Structure-activity relationships of 4-(phenylethynyl)-6-phenyl-1,4- dihydropyridines as highly selective A3 adenosine receptor antagonists
Jiang, Ji-Long,Van Rhee, A. Michiel,Chang, Louis,Patchornik, Abraham,Ji, Xiao-Duo,Evans, Patricia,Melman, Neli,Jacobson, Kenneth A.
, p. 2596 - 2608 (2007/10/03)
4-(Phenylethynyl)-6-phenyl-1,4-dihydropyridine derivatives are selective antagonists at human A3 adenosine receptors, with K(i) values in a radioligand binding assay vs [125I]AB-MECA (N6(4-amino-3-iodobenzyl)-5'- (N-methylcarbamoyl)adenosine) in the submicromolar range. In this study, structure-activity relationships at various positions of the dihydropyridine ring (the 3- and 5-acyl substituents, the 4-aryl substituent, and 1-methyl group) were probed synthetically. Using the combined protection of the 1- ethoxymethyl and the 5-[2-(trimethylsilyl)ethyl] ester groups, a free carboxylic acid was formed at the 5-position allowing various substitutions. Selectivity of the new analogues for cloned human A3 adenosine receptors was determined vs radioligand binding at rat brain A1 and A(2A) receptors. Structure-activity analysis at adenosine receptors indicated that pyridyl, furyl, benzofuryl, and thienyl groups at the 4-position resulted in, at most, only moderate selectivity for A3 adenosine receptors. Ring substitution (e.g., 4-nitro) of the 4-phenylethynyl group did not provide enhanced selectivity, as it did for the 4-styryl-substituted dihydropyridines. At the 3-position of the dihydropyridine ring, esters were much more selective for A3 receptors than closely related thioester, amide, and ketone derivatives. A cyclic 3-keto derivative was 5-fold more potent at A3 receptors than a related open-ring analogue. At the 5-position, a homologous series of phenylalkyl esters and a series of substituted benzyl esters were prepared and tested. (Trifluoromethyl)-, nitro-, and other benzyl esters substituted with electron-withdrawing groups were specific for A3 receptors with nanomolar K(i) values and selectivity as high as 37000-fold. A functionalized congener bearing an [(aminoethyl)amino]carbonyl group was also prepared as an intermediate in the synthesis of biologically active conjugates.
