Triphenylphosphine → N-tert-Butoxycarbonyl-cis-4-Hydroxy-L-Proline 3-Quinolylamide

Participants

Reaction Steps

Diethyl azodicarboxylate (40% solution in toluene, 1.4 mL) was added to a solution of triphenylphosphine (808 mg) in tetrahydrofuran (5 mL) at ñ15° C. After stirring at −15° C. to 0° C. for 30 min, trans-4-hydroxy-N-tert-butoxycarbonyl-L-proline 3-quinolylamide (A, 729 mg), and formic acid (100 mL) were added. After stirring at room temperature for 3.5 hr, formic acid (100 mL) was added, and stirring was continued for 2 hr. Then additional Mitsunobu reagent which was prepared from triphenylphosphine (803 mg) and diethyl azodicarboxylate (40% solution in toluene, 1.4 mL) was added. After the resulting solution was stirred for 3 hr, 1 N sodium hydroxide (20 mL) was added at 0° C. and stirred at room temperature for 1.5 hr. Then water (100 mL) was added to the reaction mixture and the solvents were evaporated in vacuo. The residue was extracted with ethyl acetate and the extract was washed with brine, dried over anhydrous sodium sulfate, and evaporated in vacuo. The residue was purified by silica gel column chromatography (chloroform then chloroform:methanol=30:1, v/v) to afford the title compound (576 mg) as a pale yellow sticky oil: 1H NMR (400 MHz, CD3OD) δ 1.3-1.6 (m, 9H), 1.9-2.2 (m, 1H), 2.3-2.6 (m, 1H), 3.4-3.7 (m, 3H), 4.24.5 (m, 1H), 7.60 (m, 1H), 7.70 (m, 1H), 7.90 (m, 1H), 7.98 (m, 1H), 8.72 (m, 1H), and 8.92 (m, 1H).

Provenance & Evidence