The New Method for the Preparation of Territrem B Analogues as AChE Inhibitors

Some 2-en-1-one-ebelactonyl-20-yl-benzoyl esters as Territrem B analogues were prepared with new method. Aldehyde 2 was treated with Li2CO3 in N,N-dimethylacetamide (DMAc) to give 2-en-ebelactonyl-13-aldehyde 3 which was oxidation with N-bromosuccinimide (NBS) under irradiation gave the corresponding 2-en-1-bromo-acyl bromide 4 in one step. Then 4 was esterified directly with substituted phenols to afford the corresponding esters 5 in one step. And compound 6 can be prepared from 5 through hydrolysis and oxidation in one step. During these process, the yield of 6 was increased 5%~30% than the original method, and five new compounds 3 and 5b~5e were prepared. Among all of the compounds only 6a showed 17% inhibitory activity to AChE in 10-4 mol/L.