The in vitro cytotoxicity and differential cellular sensitivity of a series of new N1-(propargyl) nitrosourea derivatives, including 1,3-bis-(2-propynyl)-1-nitrosourea (BPNU), a carmustine (BCNU) analog, were determined in the National Cancer Institute's primary antitumor drug screen. BPNU has a level of cytotoxic activity comparable to BCNU, CCNU and Methyl-CCNU. Unexpectedly, the bi-substitution of BPNU at the amino N3 position produced an inactive compound. Compared to BCNU, BPNU has a marked specificity towards leukemic cells and could potentially be useful as an anti-leukemic agent. In this series, the N1-(propargyl) group seems to induce cell line specificity.
