Trimethylsilyldiazomethane → 4-(4-Chloro-2-methoxycarbonyl-phenyl)-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of 4-(2-Carboxy-4-chloro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (0.64 g, 1.88 mmol) in toluene: methanol (9:1) was added a trimethylsilyldiazomethane (2.0 M in hexanes) (1.05 mL, 2.07 mmol) and the resulting mixture was stirred at room temperature for 1 h. The reaction mixture was concentrated in vacuo and purified using gradient elution from hexane/ethyl acetate (10%) to hexane/ethyl acetate (50%). 1H-NMR (CDCL3) δ: 1.45 (9H, s), 2.90–3.00 (4H, m), 3.50–3.60 (4H, m), 3.90 (3H, s), 6.90–7.00 (1H, d), 7.35–7.45 (1H, dd), 7.80 (1H, d). ESI-MS m/z: 355 (M+1), UV retention time: 3.11 min.

Provenance & Evidence