Design, synthesis and fluorescence analysis of potential fluorescent markers based on cardanol and glycerol

We report the synthesis and fluorescent properties of 1,4-disubstituted-1,2,3-triazoles (la-c) based on pollutant wastes and by-products from the cashew and biodiesel industries as a design for fluorescent markers. The triazoles were synthesized in four steps; catalytic hydrogenation of cardanol, reaction with epichlorohydrin, azide substitution and/or epoxide opening and, Cu catalyzed click-chemistry of the azide with the ethynylanilines (6a-c). This procedure is a potential alternative to make fluorescent markers since it affords the intermediates in high yields, enabling one to produce the products in good quantities. Moreover, triazolazobenzenes (8a-c) were prepared by azo coupling of the trizoles (1a-c) with phenol to give a new option of dyes. Evaluation of the fluorescent properties of the achieved compounds showed that all triazole derivatives displayed good fluorescence emissions in the range of 325-400 nm, with a maximum of fluorescence intensity at around 350 nm when excited between 225 and 300 nm; besides, the para-triazolaniline exhibited a dual fluorescence emission, presenting an additional emission band in the blue range (400-500 nm). (C) 2017 Elsevier Ltd. All rights reserved.