The copper-catalyzed conjugate addition-cycloacylation reaction of zinc homoenolatee with acetylenic esters or acetylenic amides is described. The zinc homoenolate is prepared from [ (ethoxycyclopropy1)oxyltrimethylsilane and zinc chloride in ether. Addition of an acetylenic amide or ester provides 2-carboxamidoor 2-carboalkoxy-3-alkylcyclopent-2-en-l-ones ingood to excellent yields. The reacti...

A series of Schiff and Mannich bases derived from 4-amino-5-(3-fluoro-phenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione were synthesized. The alkylation of 4-phenyl-5-(3-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione with propargyl bromide afforded the corresponding thiopropargylated derivative which upon treatment with the appropriate secondary amines in the presence of CuCl2 furnished the ...

An alternative synthesis of C-monoacetylenic phosphaalkenes trans-Mes*P=C(Me)(C≡CR) (Mes* = 2, 4, 6-tBu3Ph, R = Ph, SiMe3) from C-bromophosphaalkenes cis-Mes*P=C(Me)Br using standard Sonogashira coupling conditions is described. Crystallographic studies confirm cis-trans isomerization of the P=C double bond during Pd-catalyzed cross coupling, leading exclusively to trans-acetylenic phosphaalken...

In 1970 we observed that the course of the photochemical cycloadditions of certain ethylenic and acetylenic compounds to benzene, earlier reported by us [1, 2], was profoundly altered in the presence of proton donors, leading to a type of photochemical Friedel-Crafts reaction [3]. Since then, we have described, mostly in preliminary form, numerous further examples of acid catalysis in the photo...

The addition of an HDAC inhibitor, suberoylanilide hydroxamic acid (SBHA), to the culture medium of Cladosporium colocasiae, dramatically altered its metabolic profiles. Analysis of the culture broth extract led to the isolation of two new acetylenic sterols (1-2). The isolated compounds were further evaluated for their cytotoxic and antibacterial activities. Compound 1 showed activity against ...

Treatment of the 6-aldehyde derived by Moffatt oxidation of 3-O-benzoyl-1,2-O-isopropylidene-alpha-D-ribo-hexofuranose (2c) with the dibromo- or bromofluoromethylene Wittig reagents generated in situ with tetrabromomethane or tribromofluoromethane, triphenylphosphine, and zinc gave the dihalomethyleneheptofuranose analogues 3b and 3d, respectively. Acetolysis, coupling with adenine, and deprote...