Patent ID: 7045621

Claim:
A process for preparing a dibenzothiazepine compound of the following formula (5): in which each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 independently represents a hydrogen atom, an alkyl group, an alkoxy group, an alkylcarbonyl group, an aryl group, an aryloxy group, or an arylcarbonyl group, each group being optionally substituted, which comprises the steps of: reacting a nitrobenzene compound of the following formula (1): in which each of R 1 , R 2 , R 3 and R 4 has the meaning as described above, and X represents a halogen atom, with a thiosalicylic acid compound of the following formula (2): in which each of R 5 , R 6 , R 7 and R 8 has the meaning as described above, wherein the step of reacting a nitrobenzene compound of formula (1) with a thiosalicylic acid compound of formula (2) is conducted in a solvent selected from the group consisting of water, amide solvents, aliphatic alcohols, ketones, and nitriles, in the presence of a base, to obtain a 2-nitro-2′-carboxy-diphenylsulfide compound of the following formula (3): in which each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 has the meaning as described above; reducing the obtained 2-nitro-2′-carboxy-diphenylsulfide compound, in the presence of a compound selected from the group consisting of Raney-nickel, a ferrous salt, palladium/carbon, palladium/barium sulfate, a palladium compound and a platinum compound, to obtain a 2-amino-2′-carboxy-diphenylsulfide compound of the following formula (4): in which each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 has the meaning as described above; and subjecting the obtained 2-amino-2′-carboxy-diphenylsulfide compound to dehydration-condensation reaction.