X-ray crystal structure of 2-{2-acetylamino-4-[bis-(2-methoxycarbonylethyl)amino]-phenylazo}-4-methylthiazole-5-carboxylic acid ethyl ester

Crystals of the title novel red disperse dye were grown by slow evaporation from a chloroform solution and the crystal structure was determined by single crystal X-ray diffraction analysis. The dye molecule crystallises in the triclinic space group P 1 with the unit cell dimensions a = 7.561(2), b = 11.628(10) and c = 15.607(3) Å. The diffraction analysis showed that the hetarylazo skeleton of the dye is nearly planar, with the ester groups oriented up and down the plane of the molecule thus imparting it a 'Y' shape structure. The intramolecular hydrogen bonds, together with van der Waals interactions, stabilise the molecular conformation and crystal packing.