6-Methyl-2, 4-dioxytetrahydro-s-triazine (X) was prepared according to Ostrogovich5 and its absorption spectrum in the ultraviolet compared to that of allantoxaidin at different pH values. A great similarity of the absorption curves of the two compounds was noted. The wave lengths of the maximal absorption and the extinction coefficients are given in the Experimental part. Parabanic acid and hydantoin, whose structures would be similar to the ...