Studies on quinones .31. Synthesis and cyclization of substituted 2-acetylamino-1,4-benzoquinones

The synthesis of 4-acetylamino-5-hydroxybenzo[b]furans (7a), (7b), (13), and their oxidative furan ring opening to the corresponding substituted 2-acetylamino-1,4-benzoquinones (1a), (1b), and (2) are reported. The acid-induced cyclization of quinones (1a) and (2) to afford N-heterocyclic quinones (15) and (16) is also described.