An Alternative Method for the Selective Synthesis of Ortho-nitro Anilines Using Bismuth Nitrate Pentahydrate

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Nitroaromatic compounds are crucial building blocks for explosives, pharmaceuticals, and dyes.
• Bismuth nitrate pentahydrate is a common reagent, but its use in aniline nitration is not well-established.

Purpose of the Study:

• To investigate bismuth nitrate pentahydrate as a nitrating agent for anilines.
• To determine optimal reaction conditions using bismuth nitrate/acetic anhydride in DCM.

Main Methods:

• Nitration of various substituted anilines using bismuth nitrate pentahydrate and acetic anhydride.
• One-pot reaction conditions were employed before product purification.

Main Results:

• Bismuth nitrate pentahydrate proved effective for aniline nitration, showing regioselectivity for the ortho position.
• Ortho-derivatives were the major products, obtained in 50%-96% yields, with other isomers sometimes identified.

Conclusions:

• Bismuth nitrate pentahydrate serves as an efficient and safe nitrating agent for anilines.
• This method circumvents the need for hazardous concentrated acids like sulfuric and nitric acid.
• The reagent is cost-effective and requires no specialized equipment.