Synthesis of Water‐Soluble Large Naturalised Dyes Through Double Glycoconjugation

Abstract

Recently we started to develop a new class of dyes based upon the glycoconjugation of disperse dyes with mono-or disaccharides. We used the term "naturalised" to describe these dyes because we used natural lactose in the glycoconjugation process, and also because they are similar to real natural dyes, the hydrosolubility of which is based upon the saccharidic moiety attached to the chromophore, as in carminic acid or carthamin. Synthetic dyes submitted to the process of naturalisation consist of small chromophoric molecules, prevalently azoic, whereas larger dye molecules with a higher mass did not show appreciable solubility in water

A novel glycoconjugated N-acetylamino aldehyde hydrazone azo dye as chromogenic probe for cyanide detection in water

“…By this approach, the above-mentioned selectivity trend in chromogenic anion sensing is altered and thus selective choromogenic probe of a cyanide anion in pure water is demonstrated. The water solubility of the organic chemosensor is given by its glycoconjugation with the usual saccharides [29][30][31][32][33]. Cyanide is expected to be detectable by nucleophilic attack toward hydrazone functional group, which is activated by an intramolecular hydrogen-bond.…”

Suzuki and Heck Processes for the Synthesis of New Anthraquinone‐Based Glycoconjugated Dyes

“…They possess good fastness properties and hue intensity, that are key parameters in the search of the ideal colorant . Recently, we have disclosed a new class of naturalised dyes, that are glycoconjugate derivatives of chromophores, including anthraquinones ,. In this relevant case, anthraquinones bearing a phenolic group were O‐alkylated, to introduce an ethanoic acid C‐substituent suitable for dye “naturalization” .…”

Improvement on the Synthesis of Primary Amino Sugar Derivatives <i>via</i> <i>N</i>-Benzyl Intermediates

“…In the course of our program on the synthesis of sugar derived dyes [7,8], we needed to prepare a batch quantity of 6'-amino-6'-deoxy-2,3:5,6:3',4'-tri-O-isopropylidenelactose dimethyl acetal 3a [9], in order to expand the library of naturalized dyes for textile dyeing studies [10]. Literature procedures indicated sodium azide as the most popular reagent to elaborate the primary tosylate 1a to the corresponding azido intermediate [11], which would be hydrogenated to 3a (Scheme 1).…”