BENZIMIDAZOLINE-2-ONE-1-CARBOXYLIC ACID DERIVATIVES USEFUL AS 5-HT RECEPTOR ANTAGONISTS

Pharmaceutically active benzimidazoline-2-oxo-1-carbo-xylic acid derivatives are described which are 5HT receptor antagonists useful as antiemetic agents and as gastric prokinetic agents, of the following formula: (I) wherein R represents a hydrogen atom, or a C1-6 alkyl, C2-6 alkenyl or C2-6 alkynyl group; R1 and R2, which may be the same or different, represent a hydrogen atom, halogen atom, trifluoromethyl, C1-6 alkyl, C1-6 alkoxy, C1-6 alkylthio, C1-6 acyl, carboxyl, C1-6 alkoxycarbonyl, hydroxy, nitro, or amino group, optionally N-mono or di-substituted by a C1-4 alkyl group, C1-6 acylamino, C1-6 alkoxycarbonylamino, carbamoyl optionally N-mono or di-substitu-ted by C1-4 alkyl group, cyano, C1-6 alkylsulphinyl, C1-6 alkylsulphonyl, aminosulphonyl optionally Nmono or di-substituted by a C1-4 alkyl group, aminosulphonylamino optionally N-mono or di-substituted by C1-4 alkyl group; Y is oxygen or represents N - R3 in which R3 is a hydrogen atom, a C1-6 alkyl or benzyl group, optionally substituted by one or more C1-6 alkoxy groups; A is a group selected from: (a) (b) (c) (d) wherein p is 0 or 1; r is 0, 1, 2, or 3; R4 is a hydrogen atom or a C1-4 alkyl group; R5 is a hydrogen atom, C1-6 alkyl, C3-8 cycloalkyl, a C3-8 cycloalkylalkyl group having 1-4 carbons in the alkyl moiety or a phenylalkyl group having 1-4 carbons in the alkyl moiety or R5 is a group of formula wherein R6 is a hydrogen atom, C1-4 alkyl or an amino group and R7 is a hydrogen atom or C1-6 alkyl group. The processes for the preparation of the compounds of formula (I) as well as pharmaceutical compositions containing them are also described.