Trifluoroacetic Acid-Mediated Oxidative Self-Condensation of Acetophenones in the Presence of SeO₂: A Serendipitous Approach for the Synthesis of Fused [1,3]Dioxolo[4,5-d][1,3]dioxoles

Abstract

A method for the synthesis of fused 1,3-dioxolanes was developed by selfcondensation of glyoxal generated in situ by oxidation of acetophenones with SeO 2 in the presence of trifluoroacetic acid. Three molecules of the glyoxal generated by oxidation of ketone with SeO 2 condensed to form architecturally novel oxygencontaining heterocycles (3a-aryldihydro- (phenylmethanones). This reaction provides a unique methodology for the construction of four C−O bonds in a concerted fashion, generating highly embedded oxygen heterocycles from readily available ketones using affordable shelf reagents and simple reaction conditions.

Evolution and development of potent monobactam sulfonate candidate IMBZ18g as a dual inhibitor against MDR Gram-negative bacteria producing ESBLs

“…The synthetic routes of all target compounds were shown in Scheme 1 , Scheme 2 . Thiadiazole oxoacetic acid 7 was achieved through a three-step procedure from 4 in a good yield, including amino t -butyloxy carbonyl (Boc) protection, catalytic addition by lithium diisopropylamide (LDA) and α -H oxidation by SeO 2 11 . Thiazole oxoacetic acid 10 was obtained through amino triphenylmethyl protection and ester hydrolysis from 8 in a reasonable yield ( Scheme 1 A) 7 .…”