A compound of the formula wherein ** Formula ** A is hydrogen or (C1-4) alkyl, R1 is a Y-R2 group, Y is not present or is (C1-4) alkylene, whose alkylene is optionally substituted , by halogen, R2 is -P (O) (OH) (OH), or a group of the formula X is a group of the formula ring A is (C5-12) cycloalkylene, (C5-12) cycloalkenylene or phenylene , and ring B is (C5-12) unsubstituted cycloalkyl, (C5-12) cycloalkenyl or (C6-12) aryl, or (C5-12) cycloalkyl, (C5-12) cycloalkenyl or (C6-12) aryl substituted by R5, wherein R5 is halogen, halo (C1-4) alkyl, halo (C1-4) alkyloxy, carboxyl, nitro, amino, a group containing phosphorus, a group containing sulfur, or acyl or acyloxy comprising 1 to 12 carbon atoms next to the CO group, or R5 is a group -ZR6, where Z is not present or is NH, O or S, and R6 is hydrogen if Z is present, or R6 is, if Z is present or not, (C3-12) cycloalkyl, (C5-12) cycloalkenyl, (C6-12) aryl, or heterocyclyl ilo, include aromatic and aliphatic heterocyclyl comprising 3 to 12 ring members, and 1 to 4 heteroatoms selected from N, O or S, or (C1-22) alkyl, (C2-22) alkenyl, or (C2-22) alkynyl, whose alkyl, alkenyl or alkynyl is unsubstituted or substituted by (C6-12) aryl.Un compuesto de la fórmula en donde **Fórmula** A es hidrógeno o (C1-4) alquilo, R1 es un grupo Y-R2, Y no está presente o es (C1-4) alquileno, cuyo alquileno opcionalmente, está sustituido, por halógeno, R2 es -P (O) (OH) (OH), o un grupo de la fórmula X es un grupo de la fórmula el anillo A es (C5-12) cicloalquileno, (C5-12) cicloalquenileno o fenileno, y el anillo B es (C5-12) cicloalquilo no sustituido, (C5-12) cicloalquenilo o (C6-12) arilo, o (C5-12) cicloalquilo, (C5-12) cicloalquenilo o (C6-12) arilo sustituido por R5, en donde R5 es halógeno, halo (C1-4) alquilo, halo (C1-4) alquiloxi, carboxilo, nitro, amino, un grupo que contiene fósforo, un grupo que contiene azufre, o acilo o aciloxi que comprende de 1 a 12 átomos de carbono al lado del grupo de CO, o R5 es un grupo -ZR6, en do
