5-Amino-3-methyl-1-phenylpyrazole

• substituted pyrazoles
• pyrazolopyridine derivatives
• pyrazolo[3,4,-b]pyridines

1118-61-2

100-63-0

1131-18-6

In a 2-5 mL microwave reaction tube equipped with a stirrer, 3-aminobut-2-enenenitrile (164 mg, 2 mmol) was mixed with 5 mL of 1 M hydrochloric acid solution and stirred until completely dissolved to make a 0.4 M solution of the feedstock. Subsequently, phenylhydrazine (216 mg, 2 mmol) was added to this solution. The reaction tube was sealed with an aluminum cap and placed in a microwave reactor and irradiated at 150 °C for 10 min at a 'very high' absorbance setting. After completion of the reaction, it was cooled to room temperature to obtain a non-homogeneous solution containing an orange precipitate. The pH was adjusted to alkaline with 10% sodium hydroxide solution and sonicated for 5 min to promote solid precipitate formation. The precipitate was collected by filtration, washed twice with deionized water and dried to obtain a light orange solid product (292 mg, 84% yield). For products that do not precipitate easily, the basic aqueous layer can be extracted three times with dichloromethane (DCM) to separate the product. The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give the target compound.