| abstract |
This invention relates to a process for the preparation of a tetrahydrobenzimidazole derivative represented by formula I <IMAGE> in which Het represents a heterocyclic group which can be substituted by 1 to 3 substitutents selected from the group comprising a lower alkyl group, a lower alkenyl group, a lower alkinyl group, a lower cycloalkylalkyl group, an aralkyl group, a lower alkoxy group, a nitro group, a hydroxyl group, a lower alkoxycarbonyl group and a halogen atom, and X represents a single bond or -NH- which is bound to the carbon atom or to the nitrogen atom of the heterocyclic ring, or a pharmaceutically acceptable salt thereof. The compound of formula I and its salts have antagonism to 5-HT3 receptors. The said process comprises, for example, reacting a compound of formula III: <IMAGE> where X1 represents a single bond which is connected to the nitrogen atom of the heterocyclic ring or -NH bound to the carbon atom of the heterocyclic ring with a compound of formula II: <IMAGE> |