Benzopyrones. Part III. Synthesis and mass spectra of some oxopyranobenzoxazolecarboxylic esters
作者:G. Barker、G. P. Ellis
DOI:10.1039/j39710001482
日期:——
The preparation of ethyl 8-amino-7-hydroxy-4-oxochromen-2-carboxylate (1) and two of its isomers from the corresponding nitro-compounds is described. Cyclization of the Schiffbasesfrom these amino-phenols and various nitrobenzaldehydes gave the oxopyranobenzoxazoles (4)–(7). The amino-phenols (1) and (2) were also cyclized by use of phosgene or thiophosgene to give the corresponding oxo- or thioxo-oxazoles
Pharmacologically active 4-oxo-4H-chromen-2-carboxylic acids. Part II. The synthesis of 4-oxo-4H-chromen-2-carboxylic acids containing a fused imidazole or oxazole ring
作者:A. O. Fitton、B. T. Hatton
DOI:10.1039/j39700002518
日期:——
The synthesis of various 2-carboxychromones containing a fusedimidazole or oxazolering is described. The imidazolochromones were prepared either from appropriately substituted vic-acetylhydroxybenzimidazoles or from vic-diaminochromones; the oxazolochromones were obtained either from vic-aminohydroxychromones, or by decomposition of azidochromones in the presence of polyphosphoric acid and a carboxylic