Reaction of 3-formylchromones with 2-aryl-4-hydroxy-6H-1, 3-thiazin-6-ones in the presence of pyridine leads to formation of a mixture of novel N-thioaroyl-5-hydroxy-2H, 5H-pyrano [3, 2- с] chromen-2-one-3-carboxamides and 2-aryl-5-(4′-oxochromen-3′-yl)-6, 7-dihydro-4H, 5H-pyrano [2, 3-d][1, 3] thiazine-4, 7-diones. The yields of these compounds clearly depend on the nature of the substituent on the 3-formylchromone and on the reaction conditions.
![5-hydroxy-9-chloro-2-oxo-N-thiobenzoyl-2H,5H-pyrano[3,2-c]chromene-3-carboxamide结构式](https://image.chemsrc.com/caspic/470/1263273-24-0.png)
