SYNTHESIS OF 6-(MESITOYL)-1,2-NAPHTHOQUINONE

The synthesis of a compound, 6-(mesitoyl)-1,2-naphthoquinone, not described in the literature is reported and discussed in this work. The introduction of a non-polar mesitoyl moiety into the naphthoquinone molecule will enhance its lipophilicity and hence increase its bioavailability. The synthetic sequence was based on well known reactions and methods, the realization of which is usually not difficult. Purchased 2-methoxy-6-naphthalene carboxylic acid was used as the starting compound, since this molecule contains a naphthalene moiety substituted at the 2,6 - positions and the carboxyl group can be converted to a mesitoyl - group quite easily. This acid was involved in reaction with thionyl chloride to give the chloranhydride of 2-methoxy-6-naphthalene carboxylic acid. The reaction proceeded without any significant complications. In the second stage, the same well-known Friedel-Crafts acylation reaction was used. In the course of this step the main problem was demethylation of the methoxy group to form the corresponding phenol in presence of anhydrous aluminum chloride. Bromination of 6-(mesitoyl)-2-naphthol was carried out to give 1-bromo-6-(mesitoyl)-2-naphthol. Dehydrated bromine was used for this reaction. Oxidation with nitric acid of the bromo derivative was carried out and the target product was obtained as small orange crystals. The melting temperature was determined on a Stuart SMP-30 instrument. IR spectra were recorded on a Nicolet 380 FT-IR spectrometer in potassium bromide tablets. TLC was performed on Sorbfil PTLC-F-A-UV chromatographic plates, the manifestation was performed with iodine vapor. NMR spectra were recorded on a Bruker DRX-400 spectrometer (400MHz), Me4Si was used as a 1H standard, CDCl3 served as a solvent. Elemental analysis was performed on a EuroEA 3000 analyzer. The final product was analyzed on LC-MS system contained Agilent 6130 B spectrometer and Shimadzu LC-10 AT chromatograph. According to the data of physicochemical studies it was concluded that the alleged structures correspond to the actually obtained ones. The synthesized products are individual substances. For citation: Syromolotov A.V., Kimyashov A.A. Synthesis of 6-(mesitoyl)-1,2-naphthoquinone. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 7. P. 20-26. DOI: 10.6060/ivkkt.20256807.7188.