[CH3:1][O:2][C:3]1[CH:19]=[CH:18][C:6]([CH2:7][O:8][C:9]2[CH:10]=[C:11]([CH:15]=[CH:16][CH:17]=2)[C:12]([OH:14])=O)=[CH:5][CH:4]=1.[C:20]([NH:23][NH2:24])(=O)[CH3:21].C1C=CC2N(O)N=NC=2C=1.C(Cl)CCl.CC[N+](S(N=C(OC)[O-])(=O)=O)(CC)CC>CN(C=O)C>[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]([CH2:7][O:8][C:9]2[CH:10]=[C:11]([C:12]3[O:14][C:20]([CH3:21])=[N:23][N:24]=3)[CH:15]=[CH:16][CH:17]=2)=[CH:18][CH:19]=13-[(4-Methoxybenzyl)oxy]benzoic acid (9.26 g, 35.9 mmol), acethydrazide (3.98 g, 53.8 mmol), HOBT (6.59 g, 43 mmol) and EDC (10.3 g, 53.8 mmol) were weighed into a 200 mL RB flask. DMF (60 mL) was added. The mixture was stirred vigorously at room temperature. The solid dissolved within 5 min. LC-MS showed complete consumption of the acid after 30 min. DMF was removed at 60° C. under vacuum. The residue was treated with 100 mL EtOAc/water (1/1) and was allowed to stand overnight. The solid was collected via filtration and washed with EtOAc. The crude N′-acetyl-3-[(4-methoxybenzyl)oxy]benzohydrazide (8 g) was suspended in 100 mL THF and was heated under reflux in the presence of Burgess' reagent (12.8 g, 53.8 mmol) for 1 hour. The solution was cooled and directly passed through a plug of silica gel (300 gram) which was washed thoroughly with 20% acetone/hexanes. The eluent was concentrated to give the crude product as white solid.
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