4-DIMETHYLAMINOBENZHYDRAZIDE can be obtained by first preparing ethyl p-dimethylaminobenzoate from ethyl p-aminobenzoate, and then hydrolyzing it with hydrazine hydrate. Literature reports that it can be used to prepare a permanently charged hydrazine-based sugar label.
a. Weigh 1g of ethyl p-aminobenzoate into a two-necked round-bottom flask, add 40ml of acetone to dissolve it, then add 3.6g of anhydrous potassium carbonate and 14.1g of iodomethane. The reaction is carried out under nitrogen protection at 80℃ with stirring and reflux for 24 hours. After the reaction is completed, filter the reaction solution, take the filtrate, extract with dichloromethane, remove water from the organic phase with magnesium sulfate, filter out the magnesium sulfate, evaporate and concentrate, and separate and purify the product by column chromatography (mobile phase dichloromethane:methanol = 20:1) to obtain product A.
b. Add 80% hydrazine hydrate to product A at a molar ratio of 1:20, using 95% ethanol as the solvent. The reaction is carried out under nitrogen protection at 90°C under reflux. After the reaction is complete, purify by column chromatography (mobile phase: dichloromethane:methanol = 20:1) to obtain product B, namely 4-DIMETHYLAMINOBENZHYDRAZIDE.
