1-Phenyl-2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan

The ip LD50 values for 70 silatranes tested in mice ranged from 0.15 mg/kg for silatranes (with R=4-MeC6H4) to > 3000 mg/kg for 9 of the 70 cmpd. The LD50 for silatrane (R=H) itself was 100 mg/kg. In general, cmpd with alkyl, alkenyl, and alkoxy substituents were the least toxic and those with aryl and thienyl substituents the most toxic (LD50 < 1.0 mg/kg). /Silatranes/

Experiments on rats were made to study the effect of I-(chloromethyl) silatrane and I-(ethoxy) silatrane and that of triethanolamine and chloromethyl triethoxysilane on biochemical parameters of granular-fibrose tissue. The preparations were applied to a wound defect in the form of liniments. Silatranes were found to stimulate proliferation of the cells and to increase their biosynthetic activity, to favor accumulation of collagen and non-collagenic proteins, and reduction of the inflammatory phenomena. The silicon containing fragment of the silatrane molecule chloromethyl triethoxysilane produced an analogous but less marked action. ... These data indicate that silicon entering the silatrane grouping is of great importance for the occurrence of its biological activity. /Silatranes/

Only 1-ethoxy-silatrane was hydrolyzed by the diatom (Cyclolella cryptica), giving sufficient quantities of Si(OH)4 to maintain growth without exogenous Si(OH)4. In this case the diatoms multiplied by a factor of 18 within 48 hr. With silica in the medium, 1-phenylsilatrane, 1-phenyl-3,7,10-trimethylsilatrane, 1-chloromethylsilatrane and 1-chloromethyl-3,7,10-trimethoxysilatrane exhibited only slightly inhibitory activity ... . Respiration was unaffected by all the silatranes tested, but not photosynthetic oxygen evolution was reduced ... almost completely by 1-phenylsilatrane. ... In the absence of silica as nutrient in the medium, the silatranes hardly affected dark respiration within 24 hr. Conversely, the same samples showed no photosynthetic oxygen evolution after 24 hr, and 24 hr later again a negative O2 balance was produced in the light. Different silatranes produced significant differences in the final oxygen balance.

4-Ethynyl- and 4-(prop-1-ynyl)phenylsilatranes are highly toxic to houseflies (pretreated with piperonyl butoxide) and milkweed bugs (topical LD50s 3-14 ug/g) and to mice (intraperitoneal LD50s 0.4-0.9 mg/kg).