反应详情

Following the general procedure of Example 5(B), 3.88 g. of 2-amino-3-chloropyrazine and 9.21 g. of α-bromo-2-methoxy-4-methylsulfonylacetophenone were reacted to give 4.8 g. of the intermediate 8-chloro-2-(2-methoxy-4-methylsulfonylphenyl)imidazo[1,2-a]pyrazine hydrobromide. The hydrobromide salt (3.6 g.) was hydrogenated in 195 ml. of dimethylformamide and 2.7 g. of triethylamine in the presence of 1 g. of 5% palladium-on-barium sulfate. After filtration, the solution was poured into 700 ml. of ethyl acetate, washed four times with a saturated sodium chloride solution and the solvent concentrated in vacuo. At a reduced volume crystallization occurred and 540 mg. of the title product were recovered by filtration.

1. customto give 4.8 g
2. filtrationAfter filtration
3. additionthe solution was poured into 700 ml
4. washof ethyl acetate, washed four times with a saturated sodium chloride solution
5. concentrationthe solvent concentrated in vacuo
6. customAt a reduced volume crystallization
7. filtrationof the title product were recovered by filtration