Laccase‐Mediated Synthesis of Novel Substituted Phenoxazine Chromophores Featuring Tuneable Water Solubility

Abstract

Laccases are members of the blue copper oxidases family found in nature. They commonly oxidise a wide range of phenol and aniline derivatives, which in turn are involved in oxidative coupling reactions. Yet, laccases remain rarely described as biocatalysts in organic synthesis. This paper describes the chemical preparation of original sulfonated aminophenol substrates and their enzyme-mediated dimerisation into phenoxazine chromophores that feature tuneable water solubility as a function of the sulfonyl substituent. The scope and limitations of the biocatalysed synthetic process are outlined. Kinetic data were collected to evaluate the influence of physicochemical parameters. The structure of the novel phenoxazine dyes ("head-to-head" or "head-to-tail" dimer) was assessed by NMR spectroscopic analysis. Two crystalline compounds were analysed by X-ray diffraction. Such laccase-mediated synthesis (a green chemistry process) was proven to be more efficient than the chemical oxidation of o-aminophenols with silver oxide.

Enzymatic oligomerization and polymerization of arylamines: state of the art and perspectives

“…Therefore, the oxidation of 3-hydroxyorthanilic acid, a sulfonated analog of 3-HAA (SO 3 H group instead of COOH), was performed using laccase/O 2 as a biocatalyst/oxidant system, leading to the 2-amino-3-oxo-3 H -phenoxazin-1,9-disulfonic acid as the sulfonate analog of cinnabarinic acid (Bruyneel et al 2008). Similarly, numerous sulfonamide derivatives of 3-hydroxyorthanilic acid (e.g., 2-amino-3-hydroxybenzenesulfonamide, N -phenyl-2-amino-3-hydroxybenzenesulfonamide, and N -cyclohexyl-2-amino-3-hydroxybenzenesulfonamide) (Bruyneel et al 2009), as well as 3-amino-2-hydroxybenzenesulfonic acid (2-hydroxymetanilic acid) (Bruyneel et al 2009) and 3-amino-4-hydroxybenzenesulfonic acid (Forte et al 2010; Polak and Jarosz-Wilkolazka 2010), have also been transformed to corresponding phenoxazinones via laccase-catalyzed oxidative dimerization. Laccase-catalyzed synthesis was shown to be more efficient than the oxidation of o -aminophenols with silver oxide (Bruyneel et al 2009).…”

Metal coordination and tyrosinase inhibition studies with Kojic-βAla-Kojic

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 5 Kojic acid was reported as well as chelating agent for trivalent and bivalent metal ions [22][23][24][25].…”

Investigation of 3d-transition metal acetates in the oxidation of substituted dioxolene and phenols

“…Enzymes without specific condition and coordination environment around them might be non-selective viz. xanthane oxidase can generate superoxide in presence of oxygen [124,125], haloperoxidase can catalyze sulfoxidation [126], tyrosinase can perform catecholase activity [127,128] and phenoxazinone synthase activity [127,128], laccase can also perform phenoxazinone synthase activity [129,130], nitrogenase can reduce unsaturated hydrocarbon substrates, cyanate, thiocyanate [131,132]. Although most model complexes of the enzyme CO are copper complexes but a close look at the Mn complexes show that the Mn complexes exhibit good catalytic efficiency which is overall better than any other probed metal complexes suggesting that Mn is the best for similar activity in laboratory or in industry.…”