tert-Butyl piperazine-1-carboxylate → Tert-butyl 4-[4-(3-morpholin-4-yl-3-oxopropyl)phenyl]piperazine-1-carboxylate

Participants

Reaction Steps

A solution of Example 4B (400 mg, 1.342 mmol) in toluene (3.4 mL) at room temperature was treated with 1-tert-butoxycarbonylpiperazine (300 mg, 1.611 mmol), Pd2(dba)3 (61 mg, 0.0671 mmol), bis-tert-butyl biphenylphosphine (40 mg, 0.134 mmol) and sodium tert-butoxide (199 mg, 2.013 mmol), degassed three times by freeze-thaw cycle, stirred overnight and partitioned between ethyl acetate and saturated NH4Cl. The aqueous layer was extracted with ethyl acetate (3×30 mL) and the combined extracts were dried (MgSO4), filtered, and concentrated. The concentrate was purified by flash column chromatography on silica gel with 66% acetonitrile in dichloromethane to provide the desired product (317 mg, 59%). 1H NMR (300 MHz, CD3OD) δ 7.12 (2H, m), 6.91 (2H, br), 3.63 (8H, br), 3.53 (2H, t), 3.36 (2H, t), 3.10 (4H, br), 2.91 (2H, t), 2.58 (1H, t), 1.48 (9H, s).

Provenance & Evidence