Synthesis of a pyrano[2,3-b] pyridine with vinylogous hydroxamic acid structures

A new, two step synthesis of a pyrano[2,3-b]pyridine derivative 5 is described. Dehydro-acetic acid and N,N-dimethylformamide dimethylacetal was condensed to form 2 . Compound 2 was converted into 5 by reaction with hydroxylamine which opens the lactone ring.