Vat dyestuffs of the formula EQU1 wherein R represents alkyl with 1 to 4 carbon atoms, R1 and R2 represent hydrogen or alkyl with 1 to 4 carbon atoms and each of A1 and A2 represents a vattable radical with 3 to 7 condensed rings are characterized by improved resistance to alkali and are suitable for dyeing and printing the most diverse materials, in particular fibers made from natural or regenerated cellulose.