# A sustainable electrochemical phosphonylation of phenothiazine. Synthesis of a C-phosphonium betaine with powerful antibacterial activity

## TL;DR

This paper describes a new electrochemical method to create a phosphonium betaine compound with strong antibacterial properties.

## Contribution

A sustainable electrochemical method for synthesizing C-phosphonium betaine with antibacterial activity is introduced.

## Key findings

- Phenothiazine-5-ium reacts with triphenylphosphine to form C-phosphonium betaine under simple electrochemical conditions.
- The synthesized compound shows strong antibacterial activity against both Gram-positive and Gram-negative bacteria.

## Abstract

To demonstrate the capabilities of electrochemistry in the synthesis of organic compounds, we developed a facile and sustainable direct electrochemical phosphonylation of phenothiazine with triphenylphosphine. In this work, we demonstrated that electrochemically produced phenothiazine-5-ium can react with triphenylphosphine in a water/acetonitrile mixture under simple conditions using graphite and stainless steel electrodes in an undivided cell, galvanostatically and without the use of any catalyst, to synthesize the corresponding C-phosphonium betaine in good yield. The synthesized phosphonium betaine shows strong antibacterial activity against a variety of Gram positive and negative bacteria.

A novel C-phosphonium betaine were synthesized via electrochemical oxidation of phenothiazine in the presence of triphenylphosphine.