Heterocyclic derivatives as inhibitors of factor Xa

A compound of the formula I

• wherein:
• A is a 5- or 6-membered monocyclic aromatic ring containing 1, 2 or 3 ring heteroatoms selected from oxygen, nitrogen and sulphur atoms, optionally substituted by one, two or three atoms or groups selected from halo, trifluoromethyl, cyano, amino, oxo, hydroxy, nitro, (1-4C)alkyl, (1-4C)alkoxy, (1-4C)alkylamino or di-(1-4C)alkylamino;
• B1, B2, B3 and B4 are independently CH or a nitrogen atom, with the proviso that at least one of B1, B2, B3 and B4 is nitrogen;
• wherein the ring formed from B1, B2, B3 and B4 may optionally be substituted by one or two substituents selected from hydroxy, carboxy, (1-4C)alkoxycarbonyl or one of the following;
• —(CH2)m—R, —(CH2)m—NRR1, —CO—R,—CO—NRR1, —(CH2)—CO—R and —(CH2)m—CO—NRR1;
• wherein m is 1 or 2;
• R and R1 are independently selected from hydrogen, (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, hydroxy(1-4C)alkyl, carboxy(1-4C)alkyl and (1-4C)alkoxycarbonyl-(1-4C)alkyl or R and R1 may together form a 5- or 6-membered optionally substituted heterocyclic ring which may include in addition to the nitrogen atom to which R and R1 are attached 1 or 2 additional heteroatoms selected from nitrogen, oxygen and sulphur;
• X1 is CO, SO2, or CH2;
• R2 and R3 are ioined to form an ethylene group to form, together with T1, T2 and L1 a piperazine ring, which is unsubstituted or is substituted by one or two substituents independently selected from hydroxy, oxo, carboxy, (1-4C)alkoxycarbonyl or one of the following;
• —(CH2)p—R, —(CH2)p—NRR1, —CO—R, —CO—NRR1;
• —(CH2)p—CO—R and —(CH2)p—CO—NRR1;
• wherein n is 1 or 2;
• R and R1 are independently as defined above,
• Y is selected from hydrogen, halo, trifluromethyl, trifluoromethoxy, cyano, hydroxy, amino, nitro, carboxy, carbamoyl, (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, (1-4C)alkoxy, (2-4C)alkenyloxy, (2-4C)alkynyloxy, (1-4C)alkylthio, (1-4C)alkylsulphinyl, (1-4C)alkylsulphonyl, (1-4C)alkylamino, di-(1-4C)alkylamino, (1-4C)alkoxycarbonyl, N-(1-4C)alkylcarbamoyl, N,N-di-(1-4C)alkylcarbamoyl, (2-4C)alkanoyl, (2-4C)alkanoylamino, hydroxy-(1-4C)alkyl, (1-4C)alkoxy-(1-4C)alkyl, carboxy-(1-4C)alkyl, (1-4C)alkoxycarbonyl-(1-4C)alkyl, carbamoyl-(1-4C)alkyl, N-(1-4C)alkylcarbamoyl-(1-4C)alkyl and N,N-di-(1-4C)alkylcarbamoyl-(1-4C)alkyl;
• n is 1 or 2;
• and
• one of B5 and B6 is N and the other is CH;
• or a pharmaceutically acceptable salt thereof.