反应详情

To a solution of 2-cyclopentyl-6-methoxy-isonicotinic acid (2.00 g, 9.04 mmol), hydrazinecarboxylic acid benzyl ester (1.50 g, 9.04 mmol) and DIPEA (2.34 g, 18.1 mmol) in DCM (40 mL), TBTU (3.19 g, 9.94 mmol) is added. The mixture is stirred at rt for 2 h before it is diluted with EA (250 mL), washed twice with sat. aq. NaHCO3 solution (150 mL) followed by brine (100 mL), dried over MgSO4, filtered and concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 4:1 to give N′-(2-cyclopentyl-6-methoxy-pyridine-4-carbonyl)-hydrazinecarboxylic acid benzyl ester (2.74 g) as a pale yellow oil; LC-MS**: tR=0.74 min, [M+1]+=369.69; 1H NMR (D6-DMSO): δ 1.62-1.83 (m, 6H), 1.95-2.05 (m, 2H), 3.10-3.21 (m, 1H), 3.88 (s, 3H), 5.13 (s, 2H), 6.97 (s, 1H), 7.23 (s, 1H), 7.28-7.40 (m, 5H), 9.45 (s, 1H), 10.52 (s, 1H).

1. washwashed twice with sat. aq. NaHCO3 solution (150 mL)
2. dry with materialdried over MgSO4
3. filtrationfiltered
4. concentrationconcentrated
5. customThe crude product is purified by CC on silica gel eluting with heptane:EA 4:1