Regio- and stereoselective synthesis of functionalized oxazolidin-2-ones from the reaction of α-epoxyketones with urea

A regio- and stereoselective synthesis of functionalized 4,5-disubstituted oxazolidin-2-ones is reported with moderate to good yields from the reaction of α-epoxyketones with urea in the presence of p-toluenesulfonic acid as the catalyst. Correspondence: Farzad Nikpour, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416, Sanandaj, Iran.     

A facile and convenient approach to the synthesis of 3,5-diaryl-1<Emphasis Type="Italic">H</Emphasis>-pyrazoles

A simple and convenient one-pot synthesis route is described for the synthesis of 3,5-diaryl-1H-pyrazoles in short reaction times from the reaction of α-epoxyketones with semicarbazide hydrochloride under mild conditions. Correspondence: Farzad Nikpour, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416, Sanandaj, Iran.     

Photocatalytic Ring Opening of α-Epoxyketones: 1,3-Dioxolane Formation

Summary.  Photocatalytic ring opening of α-epoxyketones by 2,4,6-triphenylpyrylium tetrafluoroborate in acetone resulted in the formation of 1,3-dioxolanes as major products through C–O bond cleavage and the formation of alcoholic by-products through C–C bond cleavage. The type and nature of the substituent affects the rate of ring opening. Received June 19, 2001. Accepted (revised) November 28, 2001