Ammonium Hydroxide → 2-Phthalimido-4-methylpentanamide

Participants

Reaction Steps

To a stirred solution of 2-phthalimido-4-methylpentanoic acid (1.32 g, 5.0 mmol) in tetrahydrofuran (25 mL) are added carbonyldiimidazole (0.81 g, 5.0 mmol) and a few crystals of 4-N,N-dimethylaminopyridine followed by 15 mL of tetrahydrofuran. The reaction mixture is stirred at room temperature for 1 hour, then 1 mL of concentrated ammonium hydroxide is added. After 10 minutes, the reaction mixture is diluted with 50 mL water. The resulting slurry is partially concentrated to remove the tetrahydrofuran and filtered. The solid is washed with water and dried in vacuo (60° C., <1 mm) to afford 1.16 g (89%) of 2-phthalimido-4-methylpentanamide as a white powder: mp 173°-176° C.; 1H NMR (DMSO-d6, 250 MHz) δ 7.95-7.79 (m, 4 H, Ar), 7.61 (br s, 1 H, CONH2), 7.22 (br s, 1 H, CONH2), 4.73-4.60 (m, 1 H), 2.30-2.10 (m, 1 H), 1.95-1.80 (m, 1H), 1.45-1.25 (m, 1H); 13C NMR (DMSO-d6) d: 170.4, 167.7, 134.4, 131.5, 123.1, 51.3, 36.4, 24.7, 23.2, 20.6. Anal. Calculated for C14H16N2O3. Theoretical: C, 64.60; H, 6.20; N, 10.76. Found: C, 64.63; H, 6.11; N, 10.70.

Provenance & Evidence