Study On The Trifluoromethylation Of Hydrazones Catalyzed By AcrH₂

Drug molecules that contain trifluoromethyl group can effectively improve their lipophilicity, absorbability and metabolic stability. Thus, considerable attention has been paid to the introduce of trifluoromethyl group into organic molecules. Hydrazone compounds are important raw materials for the synthesis of carbonyl compounds, with excellent properties,significant effect in terms of pharmacological and biological activity.The incorporation of trifluoromethyl group can effectively improve hydrazones lipophilicity,absorbability and metabolic stability. Recently, the transition-metal catalyzed directed C-H trifluoromethylation have been wildly used for the trifluoromethylation of hydrazones. The NADH coenzyme model compounds' environmental friendliness and wide availability that can, in some case, outperform the inorganic and organometallic counterparts, have been recognized and extensively investigated for applications. Despite their wide employment,these transformations are almost exclusively leading to self reduction and oxygenation.Recently,the visible light photoredox catalysis, relying on the ability of phototcatalysts to engage in single-electron-transfer (SET) processes with organic substrates already attracted extensive attention. Combination of research of coenzyme model. We repored AcrH2-catalyzed direct C-H trifluoromethylation of hydrazones under visible light irradiation was reported for the first time.This paper choose AcrH2 as catalyst,an efficient method for the trifluoromethylation of hydrazones via the addition of CF3 radical to hydrazones by using CF3SO2Cl has been developed. Selecting benzaldehyde-derived hydrazones as a model substrate to screening CF3-transfer regants, solvents, light resources, base, catalyst. We determined using 1 equiv NaOAc,5 equiv CF3SO2Cl, 20% mol AcrH2,CH2Cl2 as solvent irradiation for 36 W blue LED at room temperature for 18 h. On this basis, We are expanding the hydrazones compounds substrate. Get the yield from 25%-75%. For those ortho-substrate,wo can get highest yield of 66%. The effect of electeon-donating groups is better than electron-withdrawing groups. At the same time, this article studies different substrate reactivity, and analyzes the reasons for the difference of the activities. In addition,experimental results indicated that the CF3 radical is involved in the transformation by use of a radical scavenger ethene-1,1-diyldibenzene. We also carried out the possible mechanism for this reaction.