Synthesis and study of the structure of N-succinyl chitosan Bombyx mori and their biological applications

A procedure has been developed for the preparation of Bombyx mori N-succinyl chitosan in a dimethyl sulfoxide medium for 24 h at 22 ºC, pH = 7 and a ratio of chitosan/succinic anhydride = 1:1 mol. It was found that, under the chosen synthesis conditions, the functionalization of chitosan occurs due to the substitution of the H (C2) atoms of the amino group of chitosan by the succinyl group up to 41.6%. The formation of –NH–CO– groups is indicated by IR, NMR spectral, conductometric methods. Was established a decrease in the content of total nitrogen and –NH₂ groups in the original chitosan and synthesized samples of succinyl chitosan from 8.5 to 6.2% and from 87 to 45.4%, respectively. According to the results of 1H-NMR spectroscopy, it was found that the spectra of chitosan and N-SCS have specific absorption regions at 2672 ppm and 2589 ppm, respectively. It has been shown that the IR and NMR spectra of N-succinyl chitosan samples exhibit absorption bands characteristic of –NH–CO– groups. An increase in the particle size and degree of polydispersity in solutions of N-succinyl chitosan in comparison with chitosan indicates an increase in the probability of intra- and intermolecular interactions of macromolecules of its derivative. It was found that solutions of N-succinyl chitosan have the highest fungicidal activity in comparison with chitosan and the reference fungicide preparation—Bahor, forming an inhibitory zone of 34 ± 2 mm. The results obtained are of interest in the creation of a biodegradable, non-toxic and effective fungicide for the agro-industrial complex.