Tributyltin case studies

S. J. de Mora(ed.), Tributyltin Case Study of an Environmental Contaminant, Cambridge University Press, Cambridge, 1996. 

Batley G (1996) In de Mora J (ed) Tributyltin case study of an environmental contaminant. Cambridge University Press, Cambridge, p 139... 

In a 90-day repeated dose dermal study, rabbits developed skin irritation at each of three levels tested (14, 27, and 68 mg/kg/day tributyltin fluoride) (Sheldon 1975). Deaths occurred in 7 of 10 rabbits at a level of 68 mg/kg, but surviving animals eventually returned to normal a few days after compound was withdrawn. A level of 14 mg/kg (65 applications) was stated by the authors to be a NOAEL despite local irritation at the application sites. In view of the exaggerated daily contact with the rabbit skin, this value seems reasonable since such high levels of daily exposure would not be the case in humans. However, a detailed report of this study was not available for review. 

Catalytic tributyltin hydride methodologies were also studied, with sodium borohydride used as a co-reductant <030BC4047>. In all cases examined, the yield for cyclisation of 157 to 159 was reduced substantially. This was due, in part, to the low solubility of sodium borohydride in toluene which made it necessary to employ either THF or ethanol as the reaction solvent. Unfortunately, their use promoted alkene isomerisation and substantial quantities of tra/jj-azastilbene 156 were formed as a by-product (Scheme 45). 

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