Process for preparing highly pure formylphenylboronic acids

US6420597B2 · kind B2 · utility

Assignee

• Clariant Corporation · DE

Inventors

• Frank Vollmuller · Frankfurt am Main, DE
• Andreas Meudt · Hofheim, DE
• Stefan Scherer · Büttelborn, DE

Key dates

• Filing date: Jul 2, 2001
• Grant date: Jul 16, 2002
• Expiry date: Jul 2, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F5/025
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for purifying formylphenylboronic acids of the formula (I) where the formyl function is located in the ortho, meta or para position relative to the boronic acid function, by dissolving the crude formylphenylboronic acids in an alkaline solvent having a pH in the range from 8 to 11 separating off the insoluble organic impurities and subsequently acidifying the alkaline boronic acid solution and separating off and working up the precipitated boronic acid. The crude formylphenylboronic acid is preferably dissolved in aqueous alkali metal or alkaline earth metal oxide, hydroxide, carbonate or phosphate solutions at temperatures in the range from 5 to 50° C. The formylphenylboronic acids obtained have a purity of ≧99% and are suitable as precursors for liquid-crystalline compounds, as liquid crystals or as constituents of liquid-crystalline mixtures or as pharmaceutical intermediates.