SOME NEW DERIVATIVES OF 2-PENTENEDIOIC ACID

Michael addition of N-acylaminomalonates to propynoic esters led to the (E)-4-(N-acylamino)-4-carboxy-2-pentenedioic triesters IIa - IIf. On deprotection and decarboxylation, these compounds afforded 2-(N-acyl-amino)-2-pentenedioic acid derivatives IIIa - IIIc. Dimethyl (E)-4-diazo-2-pentenedioate (IV) was prepared by direct transfer of the diazo group. On treatment of IV with 4-toluenesulfonic acid, 2-(4-toluene-sulfonyloxy)-2-pentenedioate (V) was formed. Iodination of (E)-2-pentenedioic acid led directly to the 2,4-diiodo derivative VII. From dimethyl (E)-4-oxo-2-pentenedioate the oximino ester VIIIa and the free oximino acid VIIIb were prepared.