Synthesis
General procedure for the synthesis of 3-carbonitrile-4-hydroxybenzoic acid from compound (CAS: 773837-37-9) and compound (CAS: 1131588-12-9): the product of Example 44 Step C (0.22 g, 0.72 mmol), NaCN (0.04 g, 0.8 mmol), and CuCN (0.07 g, 0.8 mmol) in anhydrous DMF (2 mL) was stirred at 110 °C for 2 h in a nitrogen atmosphere. Upon completion of the reaction, the mixture was evaporated to dryness under vacuum and the residue was suspended in water (10 mL) and the pH was adjusted with 1 M NaOH solution to about 10. The insoluble material was removed by filtration and the filtrate was acidified with dilute HCl to pH ~3. The product was extracted with dichloromethane (2 x 20 mL). The organic phases were combined and dried with anhydrous MgSO4, and the filtrate was filtered and evaporated to dryness under reduced pressure to give 3-carbonitrile-4-hydroxybenzoic acid (0.1 g, 67% yield) as a brown solid.1H-NMR (CDCl3) δ: 1.06-1.14 (m, 3H), 1.85-1.97 (m, 2H), 4.1-4.18 (m, 2H), 7.02 (d , 1H, J = 9 Hz), 8.24 (dd, 1H, J = 3, 9 Hz), 8.31 (d, 1H, J = 3 Hz).
