A formula (I) tetramethylphenyl-3-ona compound,Among them, R is nr1r2, ariloxi is replaced by halogenated, alcoxi C1-C6, trifluoride iodine and other substances, or 1 to 7 heterogeneous substances selected from O, n or s, the substitutes are halogenated, oh, nitro, etc.; R1 is h, C1-C6 tar, alquenilo C2-C6, etc.; R2 is C1-C6 tar, phenyl, phenyl, phenyl, phenyl, phenyl, etc. The most popular compounds are: 8 - (4-hydroxy-pyridine-1-il) - 2,9-dihydro-1,2,7,9-tetranitro-phenyl-3-ona, 8 - (4-phenyl-1-methyl) - 2,9-dihydro-phenyl-1,2,7,9-tetranitro-phenyl-3-ona, 8-phenyl-2,9-dihydro-1,2,7,9-tetranitro-phenyl-phenyl-phenyl-phenyl-3,There are others These compounds inhibit the detection of the enzyme (ADP ribosa) and are useful in cancer chemotherapy.REFERIDA A UN COMPUESTO TETRAAZA-FENALEN-3-ONA DE FORMULA (I), DONDE R ES NR1R2, ARILOXI SUSTITUIDO CON HALO, ALCOXI C1-C6, TRIFLUOROMETILO, ENTRE OTROS O UN HETEROCICLO DE 1 A 7 HETEROATOMOS SELECCIONADOS DE O, N O S, OPCIONALMENTE SUSTITUIDO CON HALO, OH, NITRO, ENTRE OTROS; R1 ES H, ALQUILO C1-C6, ALQUENILO C2-C6, ENTRE OTROS; R2 ES ALQUILO C1-C6, FENILO, FENOXI, BENCILOXI, ENTRE OTROS. SON COMPUESTOS PREFERIDOS: 8-(4-HIDROXI-PIPERIDIN-1-IL)-2,9-DIHIDRO-1,2,7,9-TETRAAZA-FENALEN-3-ONA, 8-(4-BENCIL-PIPERIDIN-1-ILMETIL)-2,9-DIHIDRO-1,2,7,9-TETRAAZA-FENALEN-3-ONA, 8-FENOXIMETIL-2,9-DIHIDRO-1,2,7,9-TETRAAZA-FENALEN-3-ONA, ENTRE OTROS. DICHOS COMPUESTOS INHIBEN LA POLI(ADP-RIBOSA)POLIMERASA (PARP) Y SON UTILES EN LA QUIMIOSENSIBILIZACION DE TERAPIA CONTRA EL CANCER