Abstract Lactones VI-IX were prepared on reduction of anhydrides of 4-aryl-1- methoxynaphthalene-2, 3-dicarboxylic acids IV and V with sodium borohydride in methanol. Catalytic hydrogenation on platinum of lactones VIII and IX gave lactones with hydrogenated ring A, or A and C. Lactones XII and XIII were found to possess an inhibitory effect on the growth of the tumour S 37 in experimental animals.