四川大学化学学院 2002年7月26日 21 Biological Oxidation ◼ Pioneering work by Fessenden on the metabolism of organosilanes by mammals found that phenyl and alkyl silanes were oxidized very much like their carbon analogs. ◼ A notable difference, however, was found for dimethylphenylsilane in which the silicon-hydrogen bond was rapidly oxidized in vivo
四川大学化学学院 2002年7月26日 21 Biological Oxidation ◼ Pioneering work by Fessenden on the metabolism of organosilanes by mammals found that phenyl and alkyl silanes were oxidized very much like their carbon analogs. ◼ A notable difference, however, was found for dimethylphenylsilane in which the silicon-hydrogen bond was rapidly oxidized in vivo
CH3 Si-H rapid Si-OH CH; In CH3 vivo Only CH; C X CH3 SiCH3 CH3 X=C,Si CH20H Ma jor
Example 1： Silane Analogs of DDT Example 2：Organosilane Fungicides 4.1.4 Examples for the Design of Safer Chemicals Using Silicon Substitution for Carbon
Example 1： Silane Analogs of DDT Example 2：Organosilane Fungicides 4.1.4 Examples for the Design of Safer Chemicals Using Silicon Substitution for Carbon
四川大学化学学院 2002年7月26日 24 Silane Analogs of DDT ◼ Despite the relative safety of DDT to mammals, its toxicity to other species and environmental persistence led to the ban(被禁止) of this important pesticide. ◼ In an early effort to design a more benign version of DDT, a number of silane analogs such as the DDD analog were prepared with the anticipation that these would be less environmentally persistent. ◼ While this would undoubtedly be true, all of the silanes proved to be nontoxic to insects
四川大学化学学院 2002年7月26日 24 Silane Analogs of DDT ◼ Despite the relative safety of DDT to mammals, its toxicity to other species and environmental persistence led to the ban(被禁止) of this important pesticide. ◼ In an early effort to design a more benign version of DDT, a number of silane analogs such as the DDD analog were prepared with the anticipation that these would be less environmentally persistent. ◼ While this would undoubtedly be true, all of the silanes proved to be nontoxic to insects
四川大学化学学院 2002年7月26日 25 Silane Analogs of DDT ◼ The presence of the readily oxidized siliconhydrogen bond would have been one source of instability, both environmentally and in vivo. ◼ More significant for this research however, was an SAR study that found the overall size of the DDT molecule strongly correlated with bioactivity, implicating the atomic size of the central silicon for the lack of insect toxicity for DDD and congeners(同类的)
四川大学化学学院 2002年7月26日 25 Silane Analogs of DDT ◼ The presence of the readily oxidized siliconhydrogen bond would have been one source of instability, both environmentally and in vivo. ◼ More significant for this research however, was an SAR study that found the overall size of the DDT molecule strongly correlated with bioactivity, implicating the atomic size of the central silicon for the lack of insect toxicity for DDD and congeners(同类的)