Nitric Acid → 6-Nitrothieno[3,2-b]pyridin-7-ol

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Reaction Steps

To a solution of 3.1 g of thieno[3,2-b]pyridin-7(4H)-one 13 in 90 ml of propionic acid is added 1.5 ml of fuming nitric acid at 110° C. with stirring and the mixture is refluxed for 1 hour. The cooled mixture is diluted with 50 ml of ether and the resulting crystals are collected by filtration, washed with water and ether-methanol, and dried to give 3.13 g (78%) of Compound 14. Recrystallization from dimethyl sulfoxide-methanol affords colorless crystals melting at 328°-331° C. (dec.).

Provenance & Evidence