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Regioselective Synthesis of 3‐Hydroxyorthanilic Acid and Its Biotransformation into a Novel Phenoxazinone Dye by Use of Laccase
Author(s) -
Bruyneel Frédéric,
Enaud Estelle,
Billottet Ludovic,
Vanhulle Sophie,
MarchandBrynaert Jacqueline
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700865
Subject(s) - chemistry , laccase , regioselectivity , sulfonate , biotransformation , derivative (finance) , organic chemistry , stereochemistry , combinatorial chemistry , enzyme , catalysis , financial economics , economics , sodium
A natural phenoxazinone derivative, cinnabarinic acid ( 2 , CA, R = CO 2 H), could be obtained in vitro with the aid of purified laccase from the fungi Pycnoporus cinnabarinus by oxidative dimerization of 3‐hydroxyanthranilic acid ( 1 , 3‐HAA, R = CO 2 H). With the aim of gaining access to a new class of water‐soluble chromophores and potential bioactive molecules, the regioselective sulfonation of 2‐hydroxyaniline was investigated. Straightforward insertion of a sulfonate group into a carbon–metal bond provided an efficient and selective process for the synthesis of 3‐hydroxyorthanilic acid ( 3 , 3‐HOA, R = SO 3 H). This sulfonated compound was then subjected to laccase oxidation in order to mimic the cinnabarinic acid synthesis. A practical HPLC method to study the oxidized products was developed, and the major product of biotransformation – namely 2‐amino‐3‐oxo‐3 H ‐phenoxazin‐1,9‐disulfonic acid ( 4 , LAO, R = SO 3 H) – was isolated and identified as the sulfonate analogue of cinnabarinic acid.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)