Basic Ionic Liquid as Catalyst for the Efficient and Green Synthesis of 2-Amino-3-nitrobenzonitriles in Ethanol

Abstract

A basic ionic liquid, [BmIm]OH was used as catalyst in the cyclocondensation of various kinds of vinylmalononitriles with nitroolefins in ethanol at reflux. A series of 2-amino-3-nitrobenzonitriles were obtained in reasonable yields. The straightforward and green protocol was found to be fairly efficient, and the catalyst could be recycled and reused in subsequent reactions with consistent activity. The mechanism of the reaction was discussed.

Keywords:

• 2-Amino-3-nitrobenzonitriles
• catalyze
• ionic liquid
• vinylmalononitrile

ACKNOWLEDGMENT

We are grateful to the National Natural Science Foundation of China (Nos. 20676123 and 20876147) for financial support.

Notes

^a The reaction was carried out at 80 °C or reflux for 4 h.

^b Yield of isolated product.

^c [BmIm]OH was reused three times.

^a All reactions were carried out on a 1 mmol vinylmalononitriles with 1 mmol nitroolefins in the presence of 0.2 mmol [BmIm]OH in EtOH (3 mL) at reflux.

^b Reaction time of one-pot synthesis of 2-amino-3-nitro benzonitriles from ketones (in bracket).

^c Isolated yields based on vinylmalononitrles and yields of one-pot synthesis of 2-amino-3-nitro benzonitriles based on ketones (in bracket).