Tetrahydrofurane dichloromethane → 4-[4-(2-Aminoethoxy)phenyl]-butylcarbamic acid tert-butyl ester

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Reaction Steps

{4-[4-(2-Benzyloxycarbonylaminoethoxy)phenyl]butyl}carbamic acid tert-butyl ester 15 (61.8 g) was stirred in ethanol (500 ml) with 10% palladium on carbon (6 g, wet), under one atmosphere of hydrogen. After stirring for more than 6 h, TLC (silica gel, methylene chloride/THF, 20:1) indicated reaction completion. The complete reaction was flushed with nitrogen, and suction filtered through a pad of Celite, and the pad washed with methylene chloride. The residue (41 g) after evaporation of the methylene chloride was applied to an 800 g pad of silica gel, and sequentially eluted with a mixture of THF and methylene chloride (1.4 L, 2:1), and a mixture of methylene chloride, methanol, and concentrated ammonium hydroxide (30:10:1, 2 L). The fraction containing the product was collected. Evaporation afforded the pure product 16 (32.8 g, 74% over 2 steps). 1H NMR (300 MHz, CDCl3) δ 1.44 (s, 9H), 1.50 (br s, 2H), 1.55 (m, 4H), 2.56 (t, 2H), 3.12 (m, 2H), 3.50 (m, 2H), 3.98 (t, 2H), 4.75 (br s, 1H), 5.00 (br s, 1H), 5.09 (s, 2H), 6.80 (d, 2H), 7.06 (d, 2H), 7.34 (m, 5H).

Provenance & Evidence