Triethylamine → (4-{4-[4-(1,3-Dioxo-1,3-dihydroisoindol-2-yl)pentyl]phenyl}butyl)carbamic acid benzyl ester

Participants

Reaction Steps

A solution containing compound 24 (2.53 g, 5.15 mmol) dissolved in THF (100 mL) was vacuumed and refilled with nitrogen. The procedure was repeated five times. To the solution was added palladium catalyst (0.5 g, 10% Pd on carbon, 50% wet). The flask was then pressurized with hydrogen gas to 45 psi. The mixture was then shaken overnight at room temperature. The catalyst was filtered under vacuum and washed with ethanol (3×20 mL). The filtrate and washings were combined and concentrated under vacuum. The residue was taken into dichloromethane (25 mL). To the newly formed solution was added Et3N (2.32 mL, 15.45 mmol). The solution was then cooled to 0° C. in an ice bath. CbzCl (1.32 g, 7.730 mmol) was added dropwise over 10 min to the solution, which, after the addition of CbzCl, was allowed to slowly warm to ambient temperature over 3 h and continuously stirred overnight. The reaction was quenched with water (30 mL). Two layers were separated. The organic layer was washed with brine (3×30 mL), dried over anhydrous Na2SO4, and concentrated. The resulting residue was subjected to column chromatography eluting with 0-30% ethyl acetate in hexanes to afford the desired product 25 (0.90 g, 35%) as a colorless, viscous oil: 1H NMR (300 MHz, CDCl3) δ 1.45 (d, 3H), 1.45-1.66 m, 6H), 1.72-1.86 (m, 2H), 2.06-2.16 (m, 2H), 2.55 (m, 4H), 3.20 (m, 2H), 4.38 (m, 1H), 4.80 (br, 1H), 5.08 (s, 2H), 7.04 (s, 4H), 7.34 (m, 5H), 7.69 (dd, 2H), 7.81 (dd, 1H); m/z (ESI) 499 [C31H34N2O4+H]+.

Provenance & Evidence