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

Abstract We report the synthesis and fluorescent properties of 1,4-disubstituted-1,2,3-triazoles ( 1a-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).