Synthesis and some properties of 2,3-dihydrofuro[2,3-b]quinol-4-one

Article abstract of DOI:10.1007/BF00513289

The reaction of O-ethylbutyrolactonium tetrafluoroborate with ethyl anthranilate gave the corresponding imido ester, which undergoes cyclization to a furo[2,3-b]-quinol-4-one derivative when it is heated in a solution of sodium butoxide. When the latter product is heated in diphenyl oxide, it is converted to a furo[3,2-c]-quinol-2-one derivative.