反应详情

To a stirred solution of tert-butyl 4-({[(5-amino-6-chloro-2-ethylimidazo[1,2-a]-pyridin-8-yl)carbonyl]amino}methyl)piperidine-1-carboxylate (EXAMPLE 15, Step 1, 13.71 g, 31.44 mmol) in 10% hydrochloric acid methanol solution (314 mL) was added concentrated hydrochloric acid (10 mL). After stirring at room temperature for 26 h, the mixture was concentrated to about 50 mL in vacuo. The residue was basified with an excess of sodium carbonate and then insoluble material was filtered off. The filtrate was concentrated azeotropically with ethanol and diluted with a mixture of dichloromethane and methanol (5:1, 200 mL). The formed inorganic solid was filtered off again. The filtrate was concentrated in vacuo to give a pale yellow amorphous, which was crystallized from ethanol to afford 4.79 g (45%) of the title compound as an off-white solid. Furthermore, 5.09 g (48%) of the compound was obtained from the mother liquid.

1. concentrationthe mixture was concentrated to about 50 mL in vacuo
2. filtrationinsoluble material was filtered off
3. concentrationThe filtrate was concentrated azeotropically with ethanol
4. additiondiluted with a mixture of dichloromethane and methanol (5:1, 200 mL)
5. filtrationThe formed inorganic solid was filtered off again
6. concentrationThe filtrate was concentrated in vacuo
7. customto give a pale yellow amorphous, which
8. customwas crystallized from ethanol