Alkenyl sulphonamide derivatives

A compound of the formula:

• wherein
• Ra and Rb each independently represents hydrogen;
• (1-6C)alkyl;
• aryl(1-6C)alkyl;
• (2-6C)alkenyl;
• aryl(2-6C)alkenyl or aryl, or
• Ra and Rb together with the carbon atoms to which they are attached form a (4-8C) carbocyclic ring;
• R1 represents a naphthyl group or a phenyl, furyl, thienyl or pyridyl group which is unsubstituted or substituted by one or two substituents selected independently from halogen;
• nitro;
• cyano;
• hydroxyimino;
• (1-10C)alkyl;
• (2-10C)alkenyl;
• (2-10C)alkynyl;
• (3-8C)cycloalkyl;
• hydroxy(3-8C)cycloalkyl;
• oxo(3-8C)cycloalkyl;
• halo(1-10C)alkyl;
• (CH2)yX1R9 in which y is 0 or an integer of from 1 to 4, X1 represents O, S, NR10, CO, COO, OCO, CONR11, NR12CO, NR12COCOO or OCONR13, R9 represents hydrogen, (1-10C)alkyl, (3-10C)alkenyl, (3-10C)alkynyl, pyrrolidinyl, tetrahydrofuryl, morpholino or (3-8C)cycloalkyl and R10, R11, R12 and R13 each independently represents hydrogen or (1-10C)alkyl, or R9 and R10, R11, R12 or R13 together with the nitrogen atom to which they are attached form an azetidinyl, pyrrolidinyl, piperidinyl or morpholino group;
• N-(1-4C)alkylpiperazinyl;
• N-phenyl(1-4C)alkylpiperazinyl;
• thienyl;
• furyl;
• oxazolyl;
• isoxazolyl;
• pyrazolyl;
• imidazolyl;
• thiazolyl;
• pyridyl;
• pyridazinyl;
• pyrimidinyl;
• dihydrothienyl;
• dihydrofuryl;
• dihydrothiopyranyl;
• dihydropyranyl;
• dihydrothiazolyl;
• (1-4C)alkoxycarbonyidihyd rothiazolyl;
• (1-4C)alkoxycarbonyldimethyldihydrothiazolyl;
• tetrahydro-thienyl;
• tetrahydrofuryl;
• tetrahydrothiopyranyl;
• tetrahydropyranyl;
• indolyl;
• benzofuryl;
• benzothienyl;
• benzimidazolyl;
• and a group of formula R14—(La)n—X2—(Lb)m in which X2 represents a bond, O, NH, S, SO, SO2, CO, CH(OH), CONH, NHCO, NHCONH, NHCOO, COCONH, OCH2CONH or CH═CH, La and Lb each represent (14C)alkylene, one of n and m is 0 or 1 and the other is 0, and R14 represents a phenyl or heteroaromatic group which is unsubstituted or substituted by one or two of halogen, nitro, cyano, hydroxyimino, (1-10C)alkyl, (2-10C)alkenyl, (2-10C)alkynyl, (3-8C)-cycloalkyl, 4-(1,1-dioxotetrahydro-1,2-thiazinyl), halo(1-10C)alkyl, cyano(2-10C)alkenyl, phenyl, and (CH2)zX3R15 in which z is 0 or an integer of from 1 to 4, X3 represents O, S, NR16, CO, CH(OH), COO, OCO, CONR17, NR18CO, NHSO2, NHSO2NR17, NHCONH, OCONR19 or NR19COO, R15 represents hydrogen, (1-10C)alkyl, phenyl(1-4C)alkyl, (1-10C)haloalkyl, (1-4C)alkoxycarbonyl(1-4C)alkyl, (1-4C)alkylsulfonylamino(1-4C)alkyl, (N-(1-4C)alkoxycarbonyl)(1-4C)alkylsulfonylamino-(1-4C)alkyl, (3-10C)alkenyl, (3-10C)alkynyl, (3-8C)-cycloalkyl, camphoryl or an aromatic or heteroaromatic group which is unsubstituted or substituted by one or two of halogen, (1-4C)alkyl, halo(1-4C)alkyl, di(1-4C)alkylamino and (1-4C)alkoxy and R16, R17, R18 and R19 each independently represents hydrogen or (1-10C)alkyl, or R15 and R16, R17, R18 or R19 together with the nitrogen atom to which they are attached form an azetidinyl, pyrrolidinyl, piperidinyl or morpholino group;
• and
• R2 represents (1-6C)alkyl, (3-6C)cycloalkyl, (1-6C)fluoro-alkyl, (1-6C)chloroalkyl, (2-6C)alkenyl, (1-4C)alkoxy(1-4C)alkyl, phenyl which is unsubstituted or substituted by halogen, (1-4C)alkyl or (1-4C)alkoxy, or a group of formula R3R4N in which R3 and R4 each independently represents (1-4C)alkyl or, together with the nitrogen atom to which they are attached form an azetidinyl, pyrrolidinyl, piperidinyl, morpholino, piperazinyl, hexahydroazepinyl or octahydroazocinyl group;
• or a pharmaceutically acceptable salt thereof;
• with the priviso that if R1 and Ra represent phenyl and Rb represents hydrogen, then R2 is other than 4-methylphenyl and 4-bromophenyl, and with the further priviso that if R1, Ra, and Rb represent phenyl, then R2 is other than methyl.