Efficient Synthesis of Some New Oxazolone Based Azo Dyes

As one of the largest and oldest classes of synthetic industrial dyes, azo compounds havebeen used in a wide variety of applications including but not limited to textile industry, inkjetprinting, LEDs, data storage, dye-sensitized solar cells, sensors [1], and also pharmaceuticals,foods and cosmetics [2]. In continuation of our quest for the synthesis of new azo dyes [3]and our previously reported synthesis on oxazolones [4], herein we wish to report one-pot,solvent free synthesis of oxazolone based azo dyes 2 (Fig. 1). In the present method, 5-arylazo salicylaldehydes 1 and glycine in the presence of acetic anhydride and sodium acetate canproduced oxazolones 2 in fairly high yields. The structure of the products is elucidated fromIR, UV, 1H, 13C NMR spectra as well as mass spectral data. Limitation and challenges of thisprocedure will be presented and discussed.