KETONIC MANNICH BASES DERIVED FROM 1-(5-BROMOBENZOFURAN-2-YL)ETHAN-1-ONE

Abstract

1-(5-Bromobenzofuran-2-yl)ethan-1-one has been employed as substrate in a direct Mannich reaction with common secondary amines to generate several β-aminoketones hydrochlorides. Alkylation of S- and N-nucleophiles (4-chlorothiophenol, piperazine, sulfanilamide, 3,5-dimethylpyrazole) with the dimethylamine-containing β-aminoketone derived from the aforementioned substrate has also been investigated. Reaction of the same ketonic Mannich base with phenylhydrazine afforded the corresponding 1,3-disubstituted pyrazoline, whose UV-Vis absorption has been measured in dimethylsulfoxide, toluene and chloroform at room temperature to give similar spectra having a maximum at approximately 390 nm. The fluorescence spectrum of this pyrazoline in toluene is more intense and blue-shifted compared to its emission spectrum in dimethylsulfoxide.

Keywords

• alkylation
• amine exchange
• aminomethylation
• benzofuran
• fluorescence
• pyrazoline