3-Aminopiperidine-2,6-dione hydrochloride → 2-(2,6-Dioxopiperidin-3-yl)-4-(3-ethoxy-4-methoxyphenylamino)-isoindole-1,3-dione

Participants

Reaction Steps

A mixture of 3-(3-ethoxy-4-methoxyphenylamino)phthalic acid (0.85 g, 2.6 mmol) and rac-α-aminoglutarimide hydrochloride (0.43 g, 2.6 mmol) in pyridine (10 mL) was heated to reflux for 16 hours. The mixture was cooled and evaporated under vacuum. The residue was dissolved in ethyl acetate (150 mL), washed with dilute aqueous HCl (2×100 mL) and water (2×100 mL), and evaporated. The residue was chromatographed in 95:5 methylene chloride-methanol, eluting 0.72 g of the product, in 67% yield: mp 162-164° C.; 1H NMR (CDCl3) δ 1.46 (t, J=7.0 Hz, 3H), 2.11-2.18 (m, 1H), 2.72-2.94 (m, 3H), 3.89 (s, 3H), 4.06 (q, J=7.0 Hz, 3H), 4.96 (dd, J=12.0 Hz, J=5.0 Hz, 1H), 6.76-6.89 (m, 3H), 7.14-7.19 (m, 2H), 7.43 (t, J=7.8 Hz, 1H), 7.86 (s, 1H), 8.43 (s, 1H); 13C NMR (CDCl3) δ 14.7, 22.8, 31.4, 49.0, 56.2, 64.5, 109.9, 110.8, 112.1, 113.1, 116.4, 118.5, 131.7, 132.4, 135.9, 145.2, 147.4, 149.1, 167.5, 168.4, 169.4, 171.1; Anal. calcd for C22H21N3O6: C, 62.41; H, 5.00; N, 9.92. Found: C, 62.16; H, 4.89; N, 9.72.

Provenance & Evidence