Study On The Synthesis And Activity Of 5-Methylchromone Derivatives

Chromones are a class of oxygen-containing heterocyclic compounds with a benzo-γ-pyrone ring.They are widely present in the plant kingdom and are the basic skeleton and key pharmacophore of natural active compounds flavonoids.they have a variety of pharmacological effects.A special type of chromones,5-methylchromones,contained in the tropical medicinal plant Aloe vera,have the functions of anti-oxidation,anti-aging and whitening.However,the content of chromones in Aloe vera is extremely low,and the separation and purification is difficult.which limits the wide application of aloe chromones.In this paper,the structure of aloesone was derived to find compounds with higher activity.The 2-and 7-OH of aloesone were mainly modified to obtain a series of derivatives.1.Using 3,5-dihydroxytoluene as raw material,aloesone and 8 compounds substituted with different substituents at 2-were synthesized by acylation,esterification and Baker-Venkataraman rearrangement reaction.2.Taking aloesone as the leading compound,reducing the carbonyl group on the 2-acetone group or undergoing condensation reaction with amine compounds to generate Schiff bases to synthesize 3 compounds.3.The 7-OH of the above derivatives were methylated and ethylated respectively,and 16 compounds were obtained in total.A total of 27 compounds（18 of which are new compounds）were obtained through the above three synthetic methods,and their structures were identified by NMR.Antioxidative activity studies showed that the IC₅₀ of aloe pine derivatives for scavenging DPPH was in the range of 0.098-43.41 mmol/L,and structure-activity relationship analysis found that 7-OH was the antioxidant active group of aloesone derivatives.The results of the tyrosinase activity inhibition experiment showed that the IC₅₀ of aloe pine derivatives for tyrosinase inhibition was in the range of 0.59-9.96 mmol/L.The 7-OH was methylated or ethylated,and the inhibitory activity was enhance.The activity of hexene substitution or formation of phenylhydrazone derivatives was also significantly enhanced,which proved that the 2-and 7-OH had an effect on inhibiting tyrosinase activity.