I, R= H 111, x= co II, R= CO~ CZHS IV, x= so pounds were obtained by reaction of I with ethyl chloroformate, phosgene, and thioriyl chloride, respectively. Screening by the Cancer Chemotherapy National Servire Center, Xational Institutes of Health, has revealed no significant diff erence in antineoplastic activity betweeti these derivativer and that of I, 2 as far as the Kalker carcinosarcoma 256 System is concerned. Moreover, in the KB cell ...