反应详情

A mother liquor and washings which had been resolved with L-pyroglutamic acid were combined with a 28% solution of sodium methoxide in methanol (2.6 g), concentrated and washed with water to obtain a (−)-isomer-rich crystal (3.7 g). This was dissolved in ethanol (30 ml) and combined with a solution of D-pyroglutamic acid (1.4 g) in ethanol (10 ml) at 80° C. The solution was allowed to warm to room temperature gradually, and the mixture was stirred at room temperature for 14 hours. The precipitated crystal was recovered by a filtration, washed with ethanol to obtain (−)-7-(2-chloro-5-fluorophenyl)-5-guanidinoimino-4-methyl-5,6,7,8-tetrahydroquinoline D-pyroglutamate (4.0 g). This crystal was suspended in methanol (40 ml) and combined with a 28% solution of sodium methoxide in methanol (1.6 g) and the solvent was distilled off under reduced pressure. The residue was washed with water and dried to obtain (−)-7-(2-chloro-5-fluorophenyl)-5-guanidinoimino-4-methyl-5,6,7,8-tetrahydroquinoline (2.9 g). (−)-7-(2-Chloro-5-fluorophenyl)-5-guanidinoimino-4-methyl-5,6,7,8-tetrahydroquinoline (1.7 g) was dissolved in ethanol (30 ml) and combined with methanesulfonic acid (0.97 g). The solvent was distilled off under reduced pressure and the resultant crystal was recrystallized from ethanol to obtain (−)-7-(2-chloro-5-fluorophenyl)-5-guanidinoimino-4-methyl-5,6,7,8-tetrahydroquinoline methanesulfonate (Compound I) (2.3 g, 99.5% ee).

1. distillationThe solvent was distilled off under reduced pressure
2. customthe resultant crystal was recrystallized from ethanol