Synthesis of spiropyran containing dipyrrolobenzoquinoxaline and phenylazo group

Author: Gvantsa Lagazashvili
Keywords: Spiropyran, Fischer base, condensation, dipyrrolobenzoquinoxaline
Annotation:

Indoline spiropyrans are the most promising representatives of multisensitive spirocyclic compounds. Of particular importance are the structure of spiropyran molecules, their effect on photochromic properties and reactions occurring during isomerization. The topic of the bachelor's thesis is the synthesis of bis-spirochromene based on dipyrrolobenzoquinoxaline; the introduction of a new interesting substituent into the molecule will affect its photochromic properties, structure and isomerization reactions. The synthesis of bis-spirochromene was carried out according to a known method by condensation of the bis-analogue of Fischer's indoline base, benzodipyrroloquinoxaline, with salicylic aldehyde containing a phenylazo group. The aldehyde necessary for condensation is obtained by the reaction of azoconjugation of phenyldiazonium chloride with orthovanillin. The condensation of phenylazosalicylaldehyde with the Fischer base dipyrrolobenzoquinoxaline occurs in the absolute alcohol region slowly and with good yield. The reaction product is isolated from the dark green reaction solution in the form of a green powder. The solvatochromic and photochromic properties of the product were studied and spectral analysis was carried out. Based on analysis of the proton-magnetic spectrum, it exists in solution as a bis-spirocyclic closed structure, partially isomerized into a one-way dissolved merocyanine form. This is confirmed by the extraction of ultraviolet spectra.