The DMF solution of 62 is heated to 80° C. to complete the Claisen rearrangement. Upon completion, the reaction is cooled to 0° C. A solution of benzene 1,2-diamine 18 (0.90 equiv) in DMF (7.5 mL) is sparged with nitrogen and then charged to the reaction maintaining a temperature below 25° C.; rinsing with DMF (2.5 mL) to complete the transfer. The temperature is adjusted to 20° C. and mixed until reaction completion. The temperature is adjusted to 40° C. and a 10 wt % aqueous ammonium chloride solution (95 mL) is slowly charged to crystallize the product 64. The slurry is cooled and filtered, washing the wet cake aqueous DMF and then water. The wet cake is dried to remove residual water. The crude product 64 can be recrystallized from toluene or toluene/heptane. The typical yield of 64 is 65%.
