Abstract: SYNTHESIS,LABELLING AND ANIMAL DISTRIBUTION OF TWO KINDS OF NORCANTHARIDIN DERIVATIVESLi Taihua ST5”BZ〗(Department of Chemistry,Beijing Normal University,100875) ABSTRACT  Two kinds of norcantharidin derivatives(a,b) are synthetized, then they are labelled by 125I. The best labelling conditions are: labelling temperature 80 ℃,labelling time 30 min,pH=6. The labelling yields are 95.4% and 91.6%,respectively. The two derivatives have inhibition to the carcinoma cells. The derivative(a) has well antitumor activity, and the inhibition yields to KB, HCT and Bel are 20.0%, 0 and 50.5%,respectively. The animal distribution experiments show the derivatives have the high uptake in heart, liver,lung,kideney and spleen. It should be studied whether they can be uptaken by tumor. Key words norcantharidin derivatives 125I labelling animal distribution antitumor activity