[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[S:13][C:12]([C:14]([OH:16])=O)=[CH:11][CH:10]=2)=[CH:5][CH:4]=1.S(Cl)(Cl)=O.[NH2:21][NH2:22].O>CN(C=O)C.C1(C)C=CC=CC=1.C1COCC1>[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[S:13][C:12]([C:14]([NH:21][NH2:22])=[O:16])=[CH:11][CH:10]=2)=[CH:5][CH:4]=1
To a solution of 1.8 g (7.7 mmol) of the thienoic acid in 1 mL of dry DMF and 30 mL of toluene is added 1.1 mL (15.4 mmol) of thionyl chloride and the mixture is heated at 80° C. for 3 hours. After cooling to room temperature, the solvent and excess thionyl chloride are removed under reduced pressure. The resulting residue is dissolved in 50 mL of dry THF and is added dropwise over a period of 30 minutes into a solution of 4.8 mL (154 mmol) of anhydrous hydrazine in 100 mL of dry THF while stirring at -30° C. After stirring at room temperature for 2 hours, 100 mL of water is added to the reaction mixture. The desired product is extracted with chloroform (4×100 mL), dried over anhydrous Na2SO4 and concentrated to give 1.5 g (75%) of 5-(4-methoxyphenyl)-2-thienoylhydrazine.
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