Acetic Anhydride → (R)-(-)-N-(4-Cyano-2-ethyl-phenyl)-N-[3,4-dioxo-2-(1,2,2-trimethyl-propylamino)-cyclobut-1-enyl]-acetamide

Participants

Reaction Steps

(+)-(R)-4-[3,4-Dioxo-2-(1,2,2-trimethyl-propylamino)-cyclobut-1-enylamino]-3-ethylbenzonitrile (0.36 g, 1.11 mmol), acetic anhydride (0.31 mL, 3.29 mmol) and pyridine (3.4 mL) were mixed and allowed to stand at room temperature for 24 hours. The reaction mixture was filtered to remove undissolved solid material and the filtercake was rinsed with ethyl acetate. The combined filtrate was concentrated and the resulting solid was purified by recrystallization (EtOAc/CH2Cl2) and trituration (EtOAc) to afford the title compound as 0.29 g (71%) of a white solid: mp 229°-231° C.; [α]D25 -224.43° (DMSO, c 0.0092); 1H NMR (CDCl3): δ 7.72 (s, 1H), 7.64 (m, 1H), 7.54-7.40 (m, 1H), 7.38 (m, 1H), 4.37 (m, 1H), 2.72-2.53 (m, 2H), 1.92 (s, 3H), 1.32-1.23 (m, 6H), 0.99 (d, 9H). IR (KBr): 3450, 3340, 2970, 2240, 1800, 1725, 1680, 1610 cm-1 ; MS (m/z) 367 (M+).

Provenance & Evidence