Solvent-Free,Microwave-Assisted,One-Pot Synthesis of 2-Acetyl-N,3-diaryl-4-nitro-butanamides

A combination of benzyltriethylammonium borohydride and chlorotrimethylsilane (1:1) in dichloromethane (0–25°C) has been found to be a convenient reagent system for the selective reduction of carboxylic acids to alcohols.     

Efficient synthesis of functionalized butenolides mediated by vinyltriphenylphosphonium salts in aqueous media

An efficient synthesis of 5-oxo-2,5-dihydro-3-furancarboxylate derivatives via reaction of dialkyl acetylenedicarboxylate with triphenylphosphine（Ph₃P） in the presence of activated carbonyl compounds such as ethyl pyruvate,benzil,benzoylcyanide, biacetyle or N-alkylisatins is described.     

A mild and efficient method for the synthesis of a new class of furo[3,2-c]chromenes in aqueous media

An efficient synthesis of 2-hydroxy-3-[2-oxo-2-phenylethylidene]-2-phenyl-2, 3-dihydro-4 H-furo[3, 2-c]chromene-4(2H)-one is described. This involves the reaction between dibenzoylacetylene and 4-hydroxycoumarine in the presence of NaH (10 mol %) in nearly quantitative yield. Treatment of this heterocyclic system with trimethyl chlorosilane in CHCl₃ leads quantitatively to 4-oxo-3-[2-oxo-2-phenylethylidene]-2-phenyl-3H, 4H-furo[3,2-c]chromene-1-ium chloride. Direct addition of nucleophiles, such as alcohols, amines or trialkyl phosphites to this salt in water as the solvent produces functionalized 2-phenyl-4H-furo[3,2-c] chromen derivatives in excellent yields.     

A synthesis of phosphorylated dioxohexahydropyrimidines from <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-dimethylurea,activated acetylenes,and trialkyl phosphites

An efficient synthesis of alkyl 5-(dialkoxy- phosphoryl)-1,3-dimethyl-2, 6-dioxo-hexahydropyrimidine-4-carboxylates is described. This involves the reaction of N,N′-dimethylurea and dialkyl acetylendicarboxylates in the presence of trialkyl phosphites. Under similar conditions, triphenyl phosphite led to alkyl 5-(diphenoxyphosphoryl)-1,3-dimethyl-2,6-dioxo-hexahydro-4-pyrimidinecarboxylates.