Novel applications of the hypervalent iodine chemistry. Synthesis of thiazolo-fused quinolinones

Abstract

A synthesis of thiazolo [5,4-c]quinolinone derivatives featuring the use of two different hypervalent iodine reagents has been achieved starting from ethyl benzoylacetate in an efficient way. Hydroxy(tosyloxy)phenyliodine (HITB, Kosers reagent) has been employed to functionalize the starting -ketoester 4, and phenyliodine(III)bis(trifluoroacetate) (PIFA) to perform a ring closure reaction on the corresponding N-methoxyamides 9 and 14.