Improved Protocol for Mononitration of Phenols with Bismuth(III) and Iron(III) Nitrates

Abstract

A simple and efficient multigram procedure was developed for the selective mononitration of various activated phenols. The reaction proceeded smoothly with 0.5 equivalents of Bi(NO₃)₃ · 5H₂O or Fe(NO₃)₃ · 9H₂O in acetone at ambient temperature or at reflux. The desired products were isolated in 62–93% total yield and essentially no overnitrated compounds were detected.

GRAPHICAL ABSTRACT

Keywords:

• Bismuth(III) nitrate
• iron(III) nitrate
• mono-nitration
• phenols

Notes

^a The reaction was carried out using 10 mmol of the nitrate salt and 10, 20, or 30 mmol of 1a in 100 mL of acetone at 20 °C.

^b Isolated yield of 2a in parentheses.

^c Based on the consumed nitrate.

^a Reaction conditions: Phenolic compound (20 mmol), Bi(NO₃)₃ · 5H₂O (10 mmol), and acetone (0.1 L) were stirred at 0–56 °C for 6–20 h.

^b Isolated yield based on the amount of phenol used.

^c Distribution of isomer determined by ¹H NMR.