Arylsulfanyl and heteroarylsulfanyl derivatives for treating pain

A compound of the formula I

• wherein A is selected from the group consisting of optionally substituted:
• phenyl and naphthyl;
• B is selected from the group consisting of optionally substituted:
• phenyl, thiazolyl, oxazolyl, thienyl, thiadiazolyl, isoxazole, pyrazole, furyl, pyrrolyl, imidazolyl, pyrazinyl, pyridazinyl, pyrimidyl, pyrimidone, pyrazinone and pyridazinone;
• X is selected from the group consisting of optionally substituted:
• pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrrolyl, thienyl, furyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxazolyl and isoxazolyl;
• R1 is selected from the group consisting of is CO2H, CO2R, COSO2NR2, tetrazolyl, P(O)(OR)2 and SONH2;
• R2 is selected from the group consisting of H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl and C1-3 alkylaryl;
• R3 is selected from the group consisting of H and C1-5 alkyl and
• R4 is selected from the group consisting of H and C1-5 alkyl.