Reaction Steps
To a mixture of methyl isooyanoacetate (7.1 g, 171 mmol), m-anisic acid (26 g, 171 mmol) and DBN (78 mL, 522 mmol) dissolved in DMF (1.1 L), was added DPPA (37 mL, 171 mmol) by dropwise addition. The reaction mixture was stirred about 18 hours, diluted with 50% saturated ammonium chloride solution (1 vol), extracted with diethyl ether, and the organic layers washed with water and brine before drying over MgSO4. Concentration and recrystallization (diethyl ether/hexanes) gave 24 23 g (58%), mp 75°-76° C. IR (KBr, cm-1) 3110, 3066, 1712, 1604, 1590, 1560, 1516, 1488, 1472, 1456, 1432, 1346, 1314, 1254, 1209, 1170, 1110, 1093, 1036, 892, 850, 786, 646. 1H NMR (300 MHz, CDCl3)δ 3.84 (3H, s), 3.92 (3H, s , 6.99 (1H, dd, J=8.1 Hz, J=2.I Hz) 7.36 (1 H, t, J=8.l Hz), 7.63 (1H, m), 7.72 (1H, Br.s), 7.88 (1H, s). 13C NMR (75 MHz, CDCl3) ppm 52.58, 55.60, 113.66, 116.97, 120.87, 126.66, 127.87, 129.76, 149.08, 155.61, 159.69, 165.54. m/e 234 (MH+).
