| abstract |
There is disclosed 4,10-dihydro-4,10-dioxo-1H-1-benzopyrano[3,2-b]pyridine-2-carboxylic acids, salts and esters of the formula: ##STR1## wherein R 1 is hydrogen, lower alkyl, halogen, hydroxy or lower alkoxy; R 2 is hydrogen, aralkyl or lower alkyl; R 3 is hydrogen or lower alkyl and their pharmaceutically acceptable salts. n These compounds are useful in the management of allergic conditions such as bronchial asthma, hay fever and so on. |