Pyridazines new endothelin antagonists.

A compound of formula ** ** in which: R1 is selected from: (CR7R8) n- (C3-8 cycloalkyl), (CR7R8) n-het1, (CR7R8) n aryl1, NR9R10 and (CR7R8) n- Het2, in which R7 and R8 are independently selected from H and C1-6 alkyl, and where R9 and R10 are independently selected from H or C1-6 alkyl (optionally substituted with one among aryl1, het1, Het2 or ( C3-8cycloalkyl)); n is 2-6; R2 is a) phenyl, optionally fused with het1 or Het2, b) naphthyl, optionally fused with het1 or Het2, or c) Het2, substituted said groups (a), (b) and (c) with C1-6alkyl being optionally, O (C1-6 alkyl), halo, het3, Het4, arilo2, CO2R11, OC (O) R11, CONR11R12, S (O) PR11; R3 is e) C1-6 alkyl, f) C2-6 alkenyl, g) C2-6 alkynyl, h) C3-8 cycloalkyl, may be optionally substituted groups (e), (f), (g) and (h ) with OR11, halo, NHC (O) C1-6 alkyl, Ohet1, Ohet2, OC (O) NHhet1, OC (O) NHhet2, NH2, NHC (O) Ohet2, NHC (O) NHhet2 and salts, solvates and pharmaceutically acceptable polymorphs thereof.