* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With hydrazine hydrate In dichloromethane at 0 - 20℃; for 1.5 h;
General procedure: Alcohol 1 (40 mmol) was added in portions to the solid-liquidmixture of CH2Cl2 (40 mL) and N,N'-carbonyldiimidazole (6.95 g, 42 mmol) at room temperature. The solid-liquid mixture turned into a yellowish solution, and was stirred at room temperature for 30 min after feeding. Then the solution was washed with water (2 x 40 mL). The organic phase was transferred to a three-necked flask, and cooled to 0-5 °C. Hydrazine hydrate (2.27 g, 44 mmol) was added dropwise and amorphous white solid produced after a while. The mixture was stirred at room temperature for 30 min, and then filtered. The white solid was washed with water. The filtrate was concentrated in vacuo leading to a white solid and filtered. The white solid was also washed with water. Both of the white solid was collected and dried in vacuo to get the product 3.
Reference：
[1] Journal of Combinatorial Chemistry, 2010, vol. 12, # 1, p. 69 - 74
[2] Tetrahedron, 2017, vol. 73, # 35, p. 5321 - 5326
5.A 4-(N-Benzyloxycarbonylaminomethyl)piperidine
Step A 4-(N-Benzyloxycarbonylaminomethyl)piperidine 4- Aminomethylpiperidine (1 g; 1 equivalent) and DMAP (0.054g; 0.05 equivalents) are dissolved in anhydrous dichloromethane (40 ml). N-Benzyloxycarbonylimidazole (1.7709g; 1 equivalent) [prepared as described in: S. K. Sharma, M. J. Miller and S. M. Payne, J. Med. Chem., 32, 357-367 (1989)] is added and the mixture is stirred at 25°C for 23 h. The solution is diluted with dichloromethane and washed with 1.0N sodium hydroxide. The dichloromethane layer is dried over magnesium sulfate, filtered and evaporated to dryness. The product is chromatographed on a silica gel column (60X2.5cm) using 3% increasing to 7% (10% concentrated ammonium hydroxide in methanol)-dichloromethane as the eluant to give the title compound (1.0719g; 49% yield), FABMS: m/z 249.3 (MH+).
To a cooled solution of imidazole at 000 (1.00 g, 14.7 mmol, 2equiv) in 0H2012 (18 mL),benzyl chloroformate (1.03 mL, 7.35 mmol, 1 equiv) was slowly added. After 1h45 ofstirring the white solid (imidazole hydrochloride) was filtered off. The obtained filtrate wasconcentrated, and then solubilised in ethanol (17.5 mL). In another flask the solution of<strong>[142-64-3]piperazine dihydrochloride</strong> (1.75 g, 11.03 mmol, 1.5 equiv) in water (17.5 mL) wasprepared, then added dropwisely to ethanolic solution of Cbz-imidazole. The resultedmixture was stirred for 4h30 at room temperature and then concentrated to 1h of itsvolume. Obtained aqueous phase was extracted with chloroform (4x) to remove the diacylated product, then NaOHsat was added to the previous aqueous phase (pH 9-10).The resulted aqueous phase was extracted again with chloroform (4x) to recover the monoacylated product. The organic phase with monoacylated product was washed with water (4x), dried over MgSO4 and concentrated to give (1) (0.809 g, 50% in two steps) asa colorless oil
benzyl 5-bromo-3-methyl-2-oxoindoline-1-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
47%
Stage #1: 5-bromo-3-methyl-1,3-dihydro-indol-2-one With sodium hexamethyldisilazane In tetrahydrofuran at -20℃; for 0.5h; Inert atmosphere; Schlenk technique;
Stage #2: N-benzyloxycarbonylimidazole In tetrahydrofuran at -20 - 0℃; for 3h; Inert atmosphere; Schlenk technique;
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