3-(I H-Tetrazol-5-y1) chromones converted directly to the quinone. A solution of 170 mg (0.47 mmol) of the aminoaldehyde in 32.5 ml of acetone was treated with a solution of 612 mg (2.3 mmol) of potassium nitrosodisulfonate in 16 ml of 0.167 M potassium dihydrogen phosphate and 32.5 ml of acetone. After 20 h the resulting solution was diluted with water and extracted with dichloromethane. This extract was dried (Na2S04) and concentrated ...