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Starting from 4-chloro-3,5-dinitrobenzoic acid 1, compounds 2-10 (N-alkoxy-3,5-dinitro-4-aminobenzoic acid esters where alkoxy stands for methoxy, carboxymethoxy, triphenylmethoxy, or corresponding amides) have been obtained, from which compounds 3-5 and 7-10 are new, and for the known compounds 2 and 6 the synthetic procedure has been improved. The new derivatives have been characterized by appropriate means (IR, UVVis, 1 H-and 13 C-NMR, fluorescence) and their properties were studied. Thus, depending on their structure, the compounds have acid properties, fluorescence and complexing properties with alkaline cations.

The reaction of triphenylmethane and triphenylcarbinol with nitrobenzene under thermal or ultrasonic activation was studied. It was shown beyond doubt that the thermal reaction of the aforementioned systems at 210 degrees C occurs through electron transfer. The sonochemical reactions occur at 40 degrees C, although slowly, while heating at the same temperature leaves the system unchanged. Electron transfers are also involved but an unexpected reductive process was evident.

The following new compounds were obtained by reacting 4-chloro-7-nitrobenzofurazan (NBDCl, 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.