Antiallergic pyrimido[1,2-a]quinoxalin-2-carboxylic acid derivatives

Novel pyrimidines of the formula I wherein R1 is selected from the group consisting of -OH, cation of metals and organic bases, alkoxy of 1 to 5 carbon atoms, hydrazino and 1H-tetrazol-5-yl-amino, A is selected from the group consisting of R2 is selected from the group consisting of hydrogen and alkyl of 1 to 5 carbon atoms and R3 and R4 are individually selected from the group consisting of hydrogen, halogen and alkyl and alkoxy of 1 to 5 carbon atoms with the proviso that when R1 is alkoxy of 1 to 5 carbon atoms, R2 is not hydrogen and their non-toxic, pharmaceutically acceptable acid addition salts having anti-allergic properties.