SYNTHESIS OF DIBENZO[cd, g]INDOLE

Abstract

In this paper, a synthesis method is proposed and discussed for a compound not previously described – dibenzo [cd, g] indole. For the successful synthesis of the target compound we used the classical method based on well-known procedure of indoles obtaining according to Fisher method with some changes. Commercially available derivatives of anthracene were used as the starting compound since they already contain a ready-made system of three condensed aromatic rings and they reaction activity is rather high. The corresponding diazonium salt was obtained from 9-amino anthracene by reaction with ethyl nitrite. Attempts to obtain the diazonium salt by reaction the amine with inorganic nitrites in an acidic aqueous medium did not lead to a product with an acceptable yield. 9-Antryl hydrazine was prepared by reducing the diazonium salt under mild conditions. Reduction was carried out using sulfur dioxide in aqueous sodium hydrosulfite. Formaldehyde of 9-anthrylhydrazone was obtained from anthrylhydrazine after condensation with paraformaldehyde. The target product was obtained by intramolecular cyclization of hydrazone under the action of BF3 * Et2O under the condition of high dilution and low temperature. The physicochemical characteristics of all the obtained compounds are determined. Melting point was determined on a Stuart SMP-30 instrument. IR spectra were recorded on a Nicolet 380 FT-IR spectrometer in tablets with potassium bromide. NMR spectra were recorded on a Bruker DRX-400 spectrometer (400 MHz), Me4Si was used as a 1H standard, in CDCl3 as a solvent. Elemental analysis was performed on a EuroEA 3000 analyzer. Based on the data from the above analysis methods, it was concluded that the proposed structures correspond to the real ones. In addition, we can conclude that synthesized products are individual substances.