An Efficient and Fast Procedure for the Preparation of 2-Nitrophenylamines under Microwave Conditions

Abstract

2-Nitrophenylamines were prepared in good yields from 2-chloronitrobenzen (or 2-fluoronitrobenzene) and amines in the presence of anhydrous potassium fluoride under microwave irradiation and solvent free conditions.

aminations - amines - microwave irradiation - nucleophilic aromatic substitution

References

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12

General Procedure: The preparation of N-(4′-methoxy-phenyl)-2-nitrophenylamine (3a) is representative for all synthesis.
p-Methoxy phenylamine (1.1 mmol), anhyd KF (1.1 mmol) and K₂CO₃ (1.1 mmol) were well powdered with a mortar and pestle. 2-Chloronitrobenzene (or 2-fluoronitrobenzene) (1.1 mmol) was then added to the mixture and mixed well in a glass vial. After irradiation under microwave (90 W), the mixture was treated with water and CH₂Cl₂. The organic layer was washed with 10% HCl and brine. The CH₂Cl₂ solution was dried over anhyd Na₂SO₄, evaporated and crystallized from petroleum ether (bp 60-90 °C) to give orange crystals [mp 83-86 °C (lit. ref. [4] : mp 89 °C)]. ¹H NMR (CDCl₃, 300MHz): δ = 3.85 (s, 3 H, OCH₃₎, 6.72-8.19 (8 H, aromatic H), 9.41 (s, br, 1 H, NH). MS (EI) m/z = 244 [M⁺], 229 [M⁺ - 15].