A new class of nitrosoureas. I. Synthesis and antitumor activity of 1-(2-chloroethyl)-3,3-disubstituted-1-nitrosoureas having a hydroxyl group at the .BETA.-position of the substituents.
1-(2-Chloroethyl)-3, 3-disubstituted-1-nitrosoureas (5a-m), a new class of nitrosoureas, were synthesized and tested for antitumor activities against leukemia L1210 and Ehrlich ascites carcinoma. The nitrosoureas (5e-k) having a hydroxyl group at the β-position of the substituents showed remarkable antitumor activities. In particular, 1-(2-chloroethyl)-3, 3-bis (2-hydroxyethyl)-1-nitrosourea (5k) had excellent activities and showed 5 and 16 times greater therapeutic ratios than 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea against leukemia L1210 and Ehrlich ascites carcinoma, respectively. These nitrosoureas (5e-k) appear to be activated nonenzymatically by attack of the hydroxyl group on the carbonyl group to give the oxazolidinones (6) and chloroethyl diazohydroxide (7) without generation of the isocyanates (8).