3-O-乙酰基熊果酸3-乙酰基－2-［（未）取代苯基］－2,3-二氢－1,3,4-噁二唑－5-甲酯的合成及其抗炎活性研究

Ethoxycarbonylmethyl ursolate obtained by a reaction of ursolic acid with C1CH2COOC2H5 reacted with hydrazine hydrate to give hydrazinocarbonylmethyl ursolate (3). Reaction of the hydrazide 3 with keto compounds give the corresponding hydrazones 4a~4g, which could be readily convered to 3-acetyl-2-[(un)substituted phenyl]-2, 3-dihydro-1,3,4-oxadiazol-5-methyl 3-O-acetylursolate (5a~5g) in good yields by treatment with Ac2O. The structures of new products were characterized by 1H NMR, IR and MS spectra. By the preliminary bioassay test some of such compounds show good anti-inflammatory activity. For example, compounds 5a (40 mg•kg^(-1)), 5d (40 mg•kg^(-1)) and 5g (40 mg•kg^(-1)) were better than the parent ursolic acid.