Potassium Carbonate → 2-[N'-Benzyloxycarbonyl-N-(3,5-dimethyl-benzoyl)-hydrazino]-2-methyl-propionic acid ethyl ester

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Reaktionsschritte

2-(N′-benzyloxycarbonyl-hydrazino)-2-methyl-propionic acid ethyl ester (28 g, 0.1 mol) was dissolved in 50 mL CH2Cl2 and cooled on ice. A solution of 20.7 g K2CO3 in 30 mL of water was added. A solution of 3,5-dimethylbenzoyl chloride (17 g, 0.1 mol) in 50 mL of CH2Cl2 was added drop-wise over a period of 1 hour, maintaining the temperature at 0-5° C. The mixture was stirred for 1 hour on an ice bath, and then at room temperature overnight. TLC indicated the reaction was complete. The aqueous layer was removed in a separatory funnel and the organic phase was washed with water and then brine, and then dried over Na2SO4. The solvent was removed on a rotary evaporator. The residue was slurried in hexane, filtered, and then air-dried. 2-[N′-Benzyloxycarbonyl-N-(3,5-dimethyl-benzoyl)-hydrazino]-2-methyl-propionic acid ethyl ester was obtained as a white solid (35 g), giving a single spot by TLC. 1H NMR (300 MHz, CDCl3) δ (ppm): 7.4 (s, 1H), 7.3 (m, 3H), 7.15 (m, 2H), 7.1 (s, 2H), 7.0 (s, 1H), 5.2 (d, 1H), 5.0 (d, 1H), 4.2 (m, 2H), 2.25 (s, 6H), 1.78 (s, 3H), 1.64 (s, 3H), 1.28 (t, 3H).

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