Trimethyltins

Tnmethyl(trifluororaethyl)tin can also be prepared via in situ formation and capture of tnfluorometbide by trimethyltin chlonde [13, 14] (equation 9) This tin analogue has been used as a precursor for difluorocarbene either by thermal decomposition or by reaction with sodium iodide m 1,2-dimethoxyethane This carbene generation procedure has been used to study difluorocarbene selectivity with steroidal olefins [75] (equation 10). 

The phosphonium salt method works best with nucleophilic olefins [//, 12, 16, 17, 18, 19] (Table 1 and equations 1-3) and has been used m mechanistically important studies of difluorocarbene additions to norbornadienes [20 21, 22, 23] that provided the first example of a concerted homo-l,4-addition (equation 4) A recent modification uses catalytic 1,4,7,10,13,16 hexaoxacyclooctadecane (18-crown-6) to shorten reaction times and increase yields with less nucleophilic olefins [12] (Table 1) Neither procedure, however, compares with the use of phenyl(tri-f1uoromethyl)mercury or (trifluoromethyl)trimethyltin reagents [efficient reactions with less nucleophilic olefins (equations 3 and 5) and cyclic dienes [24, 25] (equations 6 and 7)... 

Displacement of secondary allyl halides is satisfactory for the formation of symmetric allylstannanes, e.g., ( )-tributyl(l-mcthyl-2-butcnyl)stannane17, but can give 1,3-rearranged products in other cases, e.g., from 3-chlorobutene and trimethyltin reagents14 lS. Allylic cyclohexenyl chlorides react with triphenyltin lithium with clean inversion and little 1,3-transformation19,20. 

Under nitrogen, 115( 1 eq.) was reacted with BuLi (2 eq.) at 0°C for 1 h followed by treatment with trimethyltin chloride (2.5 eq.) in THF at room temperature for 30 min. Then a solution of 116 (1 eq.) and PdCl2(Ph3As)2 (0.02 eq.) in THF was combined and the mixture was stirred at reflux overnight. The polymer was precipitated with MeOH followed by filtration and dried under vacuum. GPC (polystyrene standards) Mn = 2000. 

Trimethyltin hydride has been shown to add to trimethylvinyltin, and triethyltin hydride to triethylvinyltin, to give both the 1,1- and the 1,2-distannylethanes, whereas triphenyltin hydride reacts with triphenyl vinyltin to give only the 1,2-adduct (180). 

Trimethyltin chloride reacts with carboxylic acids at 100° to give the corresponding chloride carboxylates Me2Sn(Cl)OCOR (187, 188), and diethyltin dihydride, triethyltin hydride, hexaethylditin, and bis(triethyltin) oxide have been shown to react with lead tetraacetate to give diethyltin diacetate or triethyltin acetate, as appropriate (189). 

Relatively little work has been carried out on the derivatives of the metals of Group III, but (trimethyltin)lithium has been shown to react with the trialkylmetallic compounds RgM (M = B, Al, Ga, In, or Tl) to give the products MesSnMRs Li", which decompose (B immediately, Ga and Zn in two days) to give (MesSnljSnLi (279). 

The resulting derivatives, unlike most organotin carboxylates, are hydrolyzed relatively readily in air. An X-ray crystallographic study 399) showed that trimethyltin glycinate has an intermolecularly associated, polymeric structure, with bridging amino groups. 

In trimethyltin acetate, however, bridging occurs through the carboxy-late group (355), as described in Section III. An X-ray study of the di-... 

Ascher and Nemny 495) found that residues of triphenyltin acetate on glass, resulting from the evaporation of acetone solutions thereof, were, on contact to houseflies, less toxic with rising concentration. As triphenyltin acetate is likely to be a self-associated polymer in the solid state [similar to trimethyltin acetate (355)] and in concentrated solutions, it was suggested 495) that the monomer, which exists in dilute solutions, is toxic to insects, and the polymer, nontoxic. Interestingly, in this connection, a triphenyltin methacrylate copolymer has 470) a very low mammalian toxicity (acute, oral LDso for mice >2000 mg/kg). 

Recent analytical studies have indicated that mono-, di-, and trimethyltin compounds are present in environmental samples at nanogram levels [Braman, R. S., and Tompkins, ijl.A., Analyt. Chem. 51, 12 (1979) Hodge, V. F., Seidel, S. L., and Goldberg, E. D., ibid. 51, 1256 (1979)]. 

Dimethyltin dichloride (hRf 15-20), trimethyltin chloride (h/ f 55-60), dibutyltin dichloride (h/ f 70-75) and tributyltin methoxide (h/ f 80-85) appeared in long-wavelength UV light (X = 365 nm) as yellow fluorescent chromatogram zones on a dark background. The detection limits (calculated as Sn) lay between 5 and 10 ng (dimethyltin dichloride, dibutyltin dichloride, tributyltin methoxide) and 50 ng (trimethyltin chloride) substance per chromatogram zone. 

Fig. 1 Fluorescence scan of a chromatogram track with 100 ng substance (calculated as Sn) each per chromatogram zone 1 = dimethyltin dichloride, 2 = trimethyltin chloride, 3 = dibutyltin dichloride, 4 = tributyltin methoxide.

The direct and indirect assessment of the aneuploidy-inducing potency of a number of organotin compounds was reported by Jensen et al. (1991a). The effects of dimethyltin dichloride, diphenyltin dichloride, trimethyltin chloride, tributyltin chloride, and triphenyl-tin chloride at 10 -10 mol/1 on chromosomal contractions in cultures of human peripheral lymphocytes were investigated. Diphenyltin dichloride, trimethyltin chloride, tributyltin chloride, and triphenyl-tin chloride appeared to be very strong inducers of chromosomal supercontraction, indicating that these compounds induce aneuploidy, probably by affecting... 

Feldman RG, White RF, Eriater II (1993) Trimethyltin encephalopathy. Archives of Neurology, 50(12) 1320-1324. 

Fortemps E, Amand G, Bemboir A, Lauwerys R, Laterre EC (1978) Trimethyltin peisening. Report of two cases, international Archives of Occupational and Environmental Health, 41 1-6. 

Yanofsky NN, Nierenberg D, Turco JH (1991) Acute short-term memory loss from trimethyltin exposure. Journal of Emergency Medicine, 9 137-139. 

Recently, there has been a growth of interest in the development of in vitro methods for measuring toxic effects of chemicals on the central nervous system. One approach has been to conduct electrophysiological measurements on slices of the hippocampus and other brain tissues (Noraberg 2004, Kohling et al. 2005). An example of this approach is the extracellular recording of evoked potentials from neocortical slices of rodents and humans (Kohling et al. 2005). This method, which employs a three-dimensional microelectrode array, can demonstrate a loss of evoked potential after treatment of brain tissue with the neurotoxin trimethyltin. Apart from the potential of in vitro methods such as this as biomarkers, there is considerable interest in the use of them as alternative methods in the risk assessment of chemicals, a point that will be returned to in Section 16.8. 

Trimethylaniline lb 268 Trimethyltin chloride lb 319 Trimipramine lb 352,354,355 Trinitrobenzenesulfonic acid, reagent... 

Phosphine and lithium aluminium hydride form lithium tetra-phosphinoaluminate (15) which reacts with trimethyltin chloride to give the phosphine (16). 

Although the pathway has not been established, relatively high yields of trimethyltin from inorganic tin have been observed in yeast concomitant with the degradation of butyltin compounds (Errecalde et al. 1995). Exceptionally, methionine transferase may carry out the methylation of Hg in Neurospora crassa (Landner 1971) and thiopurine methyltransferase the methylation of inorganic Se in Escherichia coli (Ranjard et al. 2003). 

Zuckerman et al. have extensively utilized this method in heterocyclic tin(II) chemistry 100). In some cases, this synthesis may also be performed with tin(II) chloride, the starting hydrochloride being coordinated by the addition of an amine 120). Free 171) and metal-bound tin(II) chloride 172) have been treated analogously with trimethyltin hydroxide to yield amorphous powders of the composition Sn(OH)2 and (CO)5MSn(OH)2 (M = Cr, W) and ClSnMe3. Unfortunately, no direct information on the structure of these compounds is available. 

Dimethylaminodimethylarsine, Trimethyltin chloride Krommes, P. et al., J. Organomet. Chem., 1976,110, 195-200 Interaction in ether to produce diazomethy ldimethylarsine is accompanied by violent foaming, and eye protection is essential. 

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