反应详情

259 g of methyl 10H-pyrazino[2,3-b][1,4]benzothiazine-8-carboxylate was dissolved in a solvent mixture of 3 l of methylene chloride with 0.5 l of tetrahydrofuran under a nitrogen atmosphere. Next, 2.5 l of a 1.01 M solution of diisobutylaluminum hydride in toluene was added dropwise thereinto while cooling the mixture so as to maintain the temperature in the system at 15° C. or below. After the completion of the reaction, the reaction mixture was poured into a mixture of 5 kg of ice with 3 l of methylene chloride. After adding 5 l of tetrahydrofuran, the resulting mixture was stirred for 1 hour. Then it was filtered and the filtrate was washed with water. After distilling off the solvent under reduced pressure, the obtained crystals were washed with diisopropyl ether to thereby give 125 g of the title compound as yellow crystals.

1. temperaturewhile cooling the mixture so as
2. temperatureto maintain the temperature in the system at 15° C. or below
3. customAfter the completion of the reaction
4. filtrationThen it was filtered
5. washthe filtrate was washed with water
6. distillationAfter distilling off the solvent under reduced pressure
7. washthe obtained crystals were washed with diisopropyl ether