Phentermine → 3-(1,1-Dimethyl-2-phenyl-ethylamino)-4-(4-methoxy-phenyl)-cyclobut-3-ene-1,2-dione

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-isopropoxy-4-(4-methoxy-phenyl)-cyclobut-3-ene-1,2-dione (0.150 g, 0.609 mmol) in ethanol (3 mL) was added 1,1-dimethyl-2-phenyl-ethylamine (0.182 g, 1.22 mmol). The mixture was stirred at 70° C. overnight then filtered hot through a pad of silica gel. The filtrate was concentrated and the resulting residue was recrystallized from ethyl acetate/hexanes to give 0.170 g (83%) of the title product as a tan solid: m.p. 150-151° C.; 1H NMR (DMSO-d6) δ 8.28(s,1H), 8.00(m,2H), 7.28(m,2H), 7.26(m,1H), 7.13(m,2H), 7.09(m,2H), 3.82(s,3H), 3.10(s,2H), 1.42(s,6H); IR (KBr) 3420, 2950, 1775, 1715, 1650, 1570, 1410, 1252, 1200, 1045, 850, 740, 700, 602, 530 cm−1; MS (m/z) 335 [M+].

Provenance & Evidence