反应详情

To a stirred mixture of 13.40 g (25.74 mmol) 3-amino-5-(3,5-dicyano-1,4-dihydro-2,6-dimethyl-4-pyridinyl)-1H-indazole-1-carboxylic acid tert-butyl ester, from Synthetic Example 18, in 335 mL dry methanol, was added 2.19 mL acetaldehyde and 2.06 mL glacial acetic acid and the resulting mixture was stirred overnight at room temperature. The reaction was cooled (ice bath) before 3.24 g sodium cyanoborohydride was added in three portions. The mixture was stirred overnight at room temperature before the reaction was concentrated to roughly half volume under vacuum. The residue was partitioned between EtOAc and saturated aqueous sodium hydrogen carbonate solution and the organic extract washed with saturated aqueous sodium chloride solution and concentrated under vacuum. The residue was taken up in hot EtOAc and allowed to cool to room temperature before being triturated with diisopropyl ether. The stirred suspension was cooled (ice bath), filtered and the crude product washed with diisopropyl ether. The product was dried under vacuum to afford 5-(3,5-dicyano-1,4-dihydro-2,6-dimethyl-4-pyridinyl)-3-(ethylamino)-1H-indazole-1-carboxylic acid tert-butyl ester (8.25 g, 76.6%) (Cpd. No. 117, Table 2). 1H-NMR (DMSO-D6, 300 MHz): δ=9.54 (br s, 1H), 7.86 (d, 1H), 7.73 (m, 1H), 7.41 (dd, 1H), 6.82 (t, 1H), 4.47 (s, 1H), 3.26-3.34 (partially obscured by solvent, m, 2H), 2.02 (s, 6H), 1.57 (s, 9H), 1.21 (t, 3H) ppm.

1. additionwas added in three portions
2. stirringThe mixture was stirred overnight at room temperature before the reaction
3. concentrationwas concentrated to roughly half volume under vacuum
4. customThe residue was partitioned between EtOAc and saturated aqueous sodium hydrogen carbonate solution
5. extractionthe organic extract
6. washwashed with saturated aqueous sodium chloride solution
7. concentrationconcentrated under vacuum
8. temperatureto cool to room temperature
9. custombefore being triturated with diisopropyl ether
10. temperatureThe stirred suspension was cooled (ice bath)
11. filtrationfiltered
12. washthe crude product washed with diisopropyl ether
13. customThe product was dried under vacuum