Abstract: Five deoxyharringtonine analogs with different alkyl groups in place of methyl group in the ester moiety have been synthesized by Reformatsky reaction of aketo-acyl-cephalotaxine and the corresponding alkyl bromoacetates. The results of animal test indicated that the replacement of the methyl group in the ester moiety with other alkyl groups caused loss of activity. The stringent structure specificity requirements in the antitumor activity in these series of compounds were once more demonstrated.