反应详情

Mannich reagent (0.8 ml, prepared according to Liebigs (1971) Ann. Chem., 743, 95-111) was added under stirring to pre-cooled (-78° C.) 5-fluoro-2-methylpyrrolo[2,3-b]pyridine (0.33 g, 2.2 mmol) under argon. The flask containing the reaction mixture was then placed in an ice bath and stirring was continued to give a white suspension. The ice lumps melted within 2 h and the resulting water bath was allowed attain room temperature. After 24 h almost all suspension had dissolved. The reaction mixture was cooled in an ice bath, diluted with deinionized water (8 ml) and extracted with diethyl ether (2×5 ml) to remove some remaining starting material and a by-product (propably the corresponding Mannich dimer). Sodium cyanide (1.08 g, 0.022 mol) was added to the water phase, assumed to contain 3-(dimethylaminomethyl)-5-fluoro-2-methylpyrrolo[2,3 -b]pyridine, and the resulting solution was refluxed for 2 h to afford a suspension which was isolated by filtration. Purification by flash chromatography (SiO 2 /CH2Cl2 :MeOH 19:1) gave 0.28 g (67%, two steps) of 3-(cyanomethyl)-5-fluoro-2-methylpyrrolo[2,3-b]pyridine.

1. additionThe flask containing the reaction mixture
2. customwas then placed in an ice bath
3. stirringstirring
4. customto give a white suspension
5. customwas allowed attain room temperature
6. dissolutionAfter 24 h almost all suspension had dissolved
7. temperatureThe reaction mixture was cooled in an ice bath
8. extractionextracted with diethyl ether (2×5 ml)
9. customto remove
10. temperaturethe resulting solution was refluxed for 2 h
11. customto afford a suspension which
12. customwas isolated by filtration
13. customPurification by flash chromatography (SiO 2 /CH2Cl2 :MeOH 19:1)