Trimethyl tin

The basic hydrolysis of tri alkyl tin haUdes and other salts forms bis(oxide)s since, except for trimethyl tin, hydroxides are unstable towards dehydration at room temperature. With tin aryl, aralkyl, and cycloalkyltin compounds, the hydroxides can be isolated. Although quite stable, they exist in mobile equiUbrium with the bisoxide and water and are easily dehydrated. Trimethyl tin hydroxide is exceptionally stable towards dehydration. 

The reaction of higher alkyl chlorides with tin metal at 235°C is not practical because of the thermal decomposition which occurs before the products can be removed from the reaction zone. The reaction temperature necessary for the formation of dimethyl tin dichloride can be lowered considerably by the use of certain catalysts. Quaternary ammonium and phosphonium iodides allow the reaction to proceed in good yield at 150—160°C (109). An improvement in the process involves the use of amine—stannic chloride complexes or mixtures of stannic chloride and a quaternary ammonium or phosphonium compound (110). Use of these catalysts is claimed to yield dimethyl tin dichloride containing less than 0.1 wt % trimethyl tin chloride. Catalyzed direct reactions under pressure are used commercially to manufacture dimethyl tin dichloride. 

Trimethvl Vinvlbenzvl Stannane—This procedure is identical to the preparation of trimethyl vinylbenzyl silane with the substitution of trimethyl tin chloride for the chlorotrimethyl silane. The following quantities were used 32.6 g (0.2136 mol) vinylbenzyl chloride in 65 mL of ether, 7.81 g (0.3211 mol) magnesium turnings. 

The conductometric titrations of the non-conducting solution of trimethyl-tin iodide in nitrobenzene (at c 7.10 2) with different donors reveal that conducting solutions are formed. The molar conductivity at a given mole ratio D (CH3 )3 SnI generally increases with increasing donicity of the donor10 (Fig. 9),... 

The absence of an EPR signal in solution or in the solid state is indicative of a singlet ground state for the diradical ( BuBP Pr2)2- An indication of the radical character of this derivative is provided by a variety of facile oxidative addition reactions (Scheme 9.12). " For example, the treatment of ( BuBP Pr2)2 with diphenyl diselenide (or elemental selenium) produces a bicyclic compound in which a selenium atom bridges the two boron atoms. Trimethyl tin hydride reacts rapidly with ( BuBP Pr2)2 to give the trans adduct. Finally, ( BuBP Pr2)2 is slowly oxidised by deuterated chloroform to produce a R,R -dichloro adduct as a mixture of cis and trans isomers. 

Tris(pyrazolyl)borate](trimethyl)tin, [HB(pz)3]SnMe3, (67) is unique, being the only authenticated example amongst triorganotin compounds of six-coordination.436... 

Determine whether implantation of embryonic neural tissue is a biologically viable method of alleviating the consequences of toxic damage prolonged in the central nervous system by trimethyl tin. 

The data reported in the literature on molecular complexes of trimethyl-tin halides demonstrate that these have a 1 1 composition with mono-... 

In a similar context, 6-18F-3,4-dihydroxyphenylalanine (6-18F-DOPA) was synthesized by direct fluorination of L-3-(3-hydroxy-4-pivaloxyphenyl)alanine (ra-P-DOPA) with Ac018F in acetic acid resulting in the 2- and 5-18F isomers. Hydrolysis of the reaction mixture in hydrochloric acid followed by HPLC separation gave 6-18F-DOPA (equation 23)44. Another application of Ac018F was reported in the synthesis of a trimethyl tin precursor of 2-oxoquazepam, 7-chloro-1 -(2,2,2-trifluoroethyl)-1,3--dihydro-5-(2-fluorophenyl)-2//-l,4-benzodiazepin-2-one, a benzodiazepine agonist, and its conversion to [18F]-2-oxoquazepam by reaction with AcQ18F (equation 24)45. 

In their studies on the use of silyl-substituted ligands as thermal and oxidative stabilizers of transition metals, Pannell and collaborators [79] show that tram- -trimethylsilyl-3- / -allyl(trimethyl)tin can be prepared in an approximate 50% yield by the Barbier reaction of a trialkyl or triarylmetal chloride with magnesium metal and l-trimethylsilyl-3-chloroprop-l-ene. With nickel(II) chloride, magnesium, a trace of mercuric(ll) chloride, and 2-trimethylsilyl-3-chloroprop-l-ene, the thermally and oxidatively stable bis( / -2-trimethylsilylallyl)nickel derivative is prepared in 36% yield. The unsubstituted derivative is thermally unstable and ignites in air. 

In most cases the trimethyl tin reagents are preferred since the byproduct. trimethyltin chloride, can easily be removed by water extraction. In the case of the water-insoluble tributyltin chloride it is necessary to add an aqueous solution of potassium fluoride to an ethereal solution of the product thereby forming insoluble tributyltin fluoride, which can be separated by... 

Trimethyl tin sodium, prepared by cleavage of hexamethylditin with either Na metal or Na naphthalene in tetraglyme is used in mechanistic studies of organotin alkalis with organic halides... 

Hexamethyldigermane resists cleavage by an Na-K alloy in 1,2-dimethoxyethane (DME) (in which the hexamethyl compounds are soluble), but the Sn—Sn bond is cleaved by the same alloy, yielding trimethyl tin potassium ... 

Salt-like trimethyl tin sodium is obtained from trimethyltin hydride with Na in liq... 

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