Synthesis and fluorescent properties of new derivatives of 4-amino-7-nitrobenzofurazan

The following new compounds were obtained by reacting 4-chloro-7-nitrobenzofurazan (NBD- Cl, 1) with five primary amines: 3b with a benzo-crown ether 18C6; 3c with an N-(α-naphthyl)- ethylenediamine group; 3d, with a 2,2,6,6-tetramethylpiperidin-N-oxyl group; 3e, with an α- picolyl group; and 3f, derived from tris(hydroxymethyl)aminomethanol. Also, from the reaction of 1 with N-methylhydroxylamine an N-hydroxy-N-methyl-NBD derivative (3g) was prepared. All these six new NBD derivatives 3b-g were studied (in comparison with the known compound 3a prepared from 1 and aniline) for their physical and chemical properties, with special emphasis on hydrophobicity, UV-Vis, fluorescence, using also structural studies trough QSPR.