Palladium-Catalyzed Efficient Synthesis of 1,3-Diformylazulene Derivatives

1,3-diformylazulene was synthesized by 1,3-dibromoazulenes,organic base and catalyst under 6×106 Pa at 120 ℃ with carbon monoxide-hydrogen for the formylation reagent,while palladium(Ⅱ) was as the catalyst,benzene as solvent.The yield was 77% under the condition the molar ratio of 1,3-dibromoazulenes,organic base and catalyst was 1∶2∶0.02.Based on the reaction,by changing the substituent,1,3-dimethylacyl-5-methyl azulene,1,3-dimethylacyl-6-tert-butyl-azulene,1,3-diformy-2,4,6-trimethyl-azulene were synthesized by acylation reactions,the yields were 68%,60%,65%.This method provides several advantages such as good yields,simple work-up procedures and mild conditions.All the products are confirmed by 1H-NMR,IR spectra and elemental analysis.