4-BROMOBENZHYDRAZIDE

Light beige powder

4-Bromobenzoic hydrazide has been used in the preparation of {2-[1-oxo-3-(4-bromophenyl)-2-propenyl]hydrazide}-4-bromobenzoic acid, {2,2?-[1,4-phenylenebis(1-oxo-2-propene-3,1-diyl)]dihydrazide}-p-bromobenzoic acid and substituted period[1,2-a]pyrimidine-2,4(3H)-diones (PPMDO).

To a 250 mL three-necked vial was added p-bromobenzoic acid (10.0 g, 49.75 mmol) and 100 mL Tetrahydrofuran, then add N,N'-carbonyl diimidazole (10.45g, 64.68mmol), TLC to monitor whether the raw material reaction is complete, after the reaction is complete, slowly add 80% hydrazine hydrate (4.93g, 78.77mmol) dropwise, dropwise, stirring the reaction for about 6 h. TLC to monitor whether the raw material reaction is complete (Expanding agent: petroleum ether /Ethyl acetate 1:1). After the reaction was completed, cooled to room temperature, concentrated under reduced pressure to remove most of the organic solvent, added about 30mL of water, pulsed at room temperature for a few moments, filtration, washed with water, resulting in a white flaky solid. After 15mL Anhydrous ethanol recrystallization yielded 9.09 g of white solid of Intermediate 3 in 85% yield. m.p. 166-167??C, consistent with literature values.