[Br:1][C:2]1[CH:3]=[C:4]([CH:17]=[CH:18][CH:19]=1)[CH2:5][O:6][C:7]1[CH:15]=[CH:14][C:10]([C:11](O)=[O:12])=[C:9]([OH:16])[CH:8]=1.O.[NH2:21][NH2:22]>CO.C1COCC1>[Br:1][C:2]1[CH:3]=[C:4]([CH:17]=[CH:18][CH:19]=1)[CH2:5][O:6][C:7]1[CH:15]=[CH:14][C:10]([C:11]([NH:21][NH2:22])=[O:12])=[C:9]([OH:16])[CH:8]=1A slurry of 4-(3-bromo-benzyloxy)-2-hydroxy-benzoic acid (2.15 g; 6.4 mmol) in MeOH (10 mL) was added hydrazine hydrate (3 mL; 62 mmol) and heated to 120° C. in a sealed metal cylinder for 40 min. The cylinder was cooled on ice and the slurry diluted with THF in order to dissolve precipitate. The clear solution was evaporated onto SiO2, and purified by filtration through a plug of Silica gel (SiO2—PE80-100° C./EtOAc=4:1; EtOAc then EtOAc/CH2Cl2=3:2) to yield after evaporation 0.9 g (42%). The compound was further purified by crystallization from MeOH/THF to yield 350 mg pure product. Mp. 201-203° C.; MS (ESI−): 335/337 (MH−).
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