Synthesis
General procedure for the synthesis of 4-methylphthalimide from 5-methylisobenzofuran-1,3-dione (Intermediate Example 71): 5-methyl-2,3-dihydro-1H-isoindole xylene (15 mL) was added to a reaction vial containing 4-methylphthalic anhydride (3.0 g) and urea (1.2 g). The reaction mixture was stirred at 150°C overnight. After completion of the reaction, the mixture was cooled to room temperature and the precipitated crystals were collected by filtration and washed sequentially with ethanol and water. The resulting crystals were dried under reduced pressure to give 4-methylphthalimide (2.4 g, 82% yield) as white crystals.1H NMR (CDCl3) δ (ppm): 2.5 (3H, s), 7.5 (1H, d), 7.6 (1H, s), 7.7 (1H, s).
References
[1] Patent: EP1595866, 2005, A1. Location in patent: Page/Page column 27
[2] Bulletin of the Chemical Society of Japan, 2001, vol. 74, # 10, p. 1975 - 1976
[3] Bioorganic and Medicinal Chemistry Letters, 2008, vol. 18, # 14, p. 4159 - 4162
[4] Patent: EP1445249, 2004, A1. Location in patent: Page 133
