H. Borowiec et al., A ROUTE TO 4-HYDROXY-2-QUINOLONE INVOLVING AN ALPHA,ALPHA'-DIOXOKETENE - A STRUCTURAL PROOF, Journal of chemical research. Synopses, (5), 1996, pp. 248-249
An efficient synthesis of a substituted 4-hydroxy-2-quinolone from an
amide derivative of furan-2,3-dione via an alpha,alpha'-dioxoketene is
discussed and is supported by a crystal structure of the product.