Studies on chemical carcinogens and mutagens. XXXIX Effects of silicon and germanium substitutions on physicochemical properties and cytotoxicity of N-alkyl-N-nitrosoureas.
作者:SHIN-ICHI NINOMIYA、FEN-ZHI LIU、HIROAKI NAKAGAWA、KOHFUKU KOHDA、YUTAKA KAWAZOE、YOSHIRO SATO
DOI:10.1248/cpb.34.3273
日期:——
N-Trialkylsilymethyl- and N-trialkylgermylmethyl-N-nitrosoureas, which are analogues of N-neopentyl-N-nitrosourea, were synthesized and tested for cytotoxicity to leukemia L1210 cells. Rates, activation energies, and entropies of activation of the hydrolytic activation of these derivatives were determined. The chemoselectivity and partition properties were also determined in terms of the Swain-Scott's substrate constant and logk', respectively. In aqueous media, all the Si- and Ge-containing nitrosoureas examined underwent hydrolysis accompanied by the ready cleavage of the Si-C or Ge-C bond to give methanol. From these nitrosoureas, the corresponding diazoalkanes were synthesized and reacted with a carboxylic acid in benzene containing alcohols. The results indicated that the Ge-C bond is more susceptible to hydrolysis than the Si-C bond. More lipophilic dimethylphenylsilyl and -germyl derivatives were more toxic to L-1210 than the crresponding trimethyl derivatives.
N-三烷基硅甲基和N-三烷基锗甲基-N-硝唑脲的合成与N-新戊基-N-硝唑脲类似,并测试了其对白血病L1210细胞的细胞毒性。这些衍生物的水解活化速率、活化能和活化熵得到了确定。化学选择性和分配特性也分别通过Swain-Scott基底常数和logk'进行测定。在水介质中,所有检验的含硅和含锗的硝唑脲都发生了水解,伴随Si-C或Ge-C键的断裂,生成甲醇。从这些硝唑脲中合成了相应的二氮烷,并与含醇的苯中羧酸反应。结果表明,Ge-C键比Si-C键更容易发生水解。更具脂溶性的二甲基苯基硅和锗衍生物的毒性比相应的三甲基衍生物对L-1210细胞更强。