Sulfuric Acid → 4-Aminomethyl-4-(4-iodo-phenyl)-piperidine-1-carboxylic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsschritte

A solution of LiAlH4 (8.5 mL of a 1.0M solution in THF, 8.5 mmol, 3.5 eq.) was cooled to 0° C. and concentrated H2SO4 (0.43 mL, 7.6 mmol, 3.2 eq.) was added in a drop-wise fashion. The resulting white slurry was stirred at room temperature for 0.5 h, then heated to 30° C. for 0.5 h. The reaction was cooled to room temperature and a solution of 4-cyano-4-(4-iodo-phenyl)-piperidine-1-carboxylic acid tert-butyl ester (1 g, 2.43 mmol, 1 eq.) in THF (3 mL) was added over 0.25 h. The mixture was heated to 55° C. and monitored by TLC. After 5 h the reaction was cooled to room temperature and quenched by careful addition of H2O (0.323 mL), 1N NaOH (0.646 mL) and H2O (0.97 mL). This mixture was diluted with CH2Cl2 (25 mL) and stirred vigorously for 1 h and then filtered through a pad of celite®. The salts were washed with CH2Cl2 (5×25 mL) and the combined washings were concentrated by rotary evaporation to give the crude product as a yellow solid (0.597 g) which was purified by flash column chromatography by eluting with 1% MeOH/1% TEA/CH2Cl2 to give the title compound 4-aminomethyl-4-(4-iodo-phenyl)-piperidine-1-carboxylic acid tert-butyl ester (0.26 g, 0.625 mmol, 26%) as a colorless oil. 1H NMR (CDCl3): δ 7.81 (d, 2H), 7.17 (d, 2H), 3.82 (m, 2H), 3.145 (m, 2H), 2.86 (s, 2H), 2.24 (m, 2H), 1.80 (m, 2H), 1.65 (br. m., 2H), 1.56 (s, 9H).

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