Machida Yoshimasa, S. Nomoto, S. Negi
Aug 11, 1981
Citations
0
Influential Citations
10
Citations
Journal
Synthetic Communications
Abstract
Abstract 4-Oxo-4-H-1-benzopyran-3-carboxylic acids and their derivatives (esters and amides), 2, are known to possess interesting pharmacological activities.1 As part of our synthetic studies of biologically active compounds, we needed to prepare a variety of 2 (carboxylic acids, esters, amides, etc.). An elegant method for the preparation of 4-oxo-4H-1-benzopyran-3-carboxaldehydes, 1, was reported independently by Nohara et al. 2 and Harnish.3 However, despite a rather extensive effort by Nohara et al., the oxidation of 1 to 2 (Y=OH) has not been realized in good yield; thus the yields by Jones oxidation, the best reported method, ranged only from 9.5 to 39%.4