The reaction between 2: 4: 6-triamino-5-nitrosopyrimidine and NN-di-2'-chloroethyl-or NN-di- 2'-chloropropyl-2-naphthylamine in acetic acid in the presence of anhKdrous sodium acetate yields 6: 8-diamino-5: 7: 9: 10-tetra-aza-1: 2-benzanthracene (I; R= R'= NH,), which is also,