Tri-n-butyltin bromide

Tri-n-butyltin bromide (TBT), triethyltin bromide (TET), and trimethyltin chloride (TMT) inhibited the cardiac SR Ca uptake (Figure 4.1.2) and Ca +-ATPase (Figure 4.1.3) in vitro in rat heart in a concentration-dependent manner. The order of potency for Ca +-ATPase as determined by IC50, is TBT (2 pM) > TET (63 pM) > TMT (280 pM). For Ca uptake, it followed the same order, i.e., TBT (0.35 pM) > TET (10 pM) > TMT (440 pM). In agreement with them vifro results, both cardiac SR Ca +-ATPase and Ca uptake were significantly inhibited in vivo in rats treated with these organotin compounds... 

In this example, reaction solvent is evaporated and the tetradeutero-adamantane and tri-n-butyltin bromide dissolved in ether and washed with saturated KF in water (ca. 10 g in 100 ml). The resulting polymeric tri-n-butyltin fluoride is insoluble in both water and organic solvent and is removed by filtration under vacuum. The desired product is then purified by sublimation. 

E. Vogel, H.-J. Altenbach, and D. Cremer, Angew. Chem., Int. Ed. Engl. 11,935 (1972). This paper also describes the conversion of bromide (5a) to parent 1,4-dioxocin by tri-n-butyltin hydride. 

Arylation of silyl enol ethers.1 Silyl enol ethers of methyl n- or sec-alkyl ketones undergo arylation when treated with an aryl bromide and tri-n-butyltin fluoride and a... 

Reduction of acyl chlorides to aldehydes,13 Tri-n-butyltin hydride reduces acyl chlorides to a mixture of aldehydes and esters. In the presence of a soluble Pd catalyst usually Pd[P(C6H5)3]4, only aldehydes obtain. This reduction is very general, and yields are usually > 80%. Reduction of double bonds is a minor competing reaction with a, / -unsaturatcd substrates (< 5% reduction). Of other reducible groups, only an allylic bromide group competes with the COC1 group. 

Loffler has examined the reduction of the adduct (2) of hydrogen bromide with bullvalene (1) with tri-n-butyltin hydride in benzene (80°) with azobisisobutyronitrile (AIBN, 1,45) as initiator. The reaction leads to five products (3)-(7). 

Iriniethoxyborohydridc. Stannous bromide. Stannous chloride. Teltamethylammonium borohydride. Thioglycolic acid. Tin. Titanium tetrachloride. Tri-/-butylaluminum. Tri-n-butyltin hydride. Triethylene glycol (see Zinc). Triethyl phosphite. Trimethylamine borane. Trimethylammonium formate. Trimethylsilane (indirect). Triphenyltin hydride. Tris-(tripbenylphosphine)chlor(X hodium. Zinc. Zinc amalgam. Zinc-Copper couple. Zinc hydrosulfide. 

Grignard reagents were not interconverted. No rearranged products were formed in the reaction of the bromide corresponding (25) with magnesium or with tri-n-butyltin hydride, or in reaction of the corresponding mercuric bromide derivative with sodium-potassium alloy. 

The synthesis of hepialone (928), the principal sex pheromone produced by the male moth Hepaialus californicus, relies on (7 )-1,2-epoxybutane (925) as the source of chirality (Scheme 136) [204]. Epoxide 925 is in turn synthesized from (7 )-malic acid by reduction of the THP derivative 921b with lithium aluminum hydride and conversion of diol 922 to ditosylate 923 and then dibromide 924. Removal of the protecting group followed by base-catalyzed cyclization results in epoxide formation. Debromination of the primary bromide with tri-n-butyltin hydride affords the desired oxirane 925. 

Whereas the syn-bromides (707)—(709) are reduced smoothly by tri-n-butyltin deuter-ide in hot benzene to give predominantly inverted products, the anti-bromides (710) and (712) do not react except under more forcing conditions, when products of completely retained configuration are obtained. Competitive reduction of (708) and (711)... 

The following chemicals are utilized without further purification (from Ventron-Alfa Inorganics unless noted otherwise), dibutyltin dichloride (Fisher), diethyltin dichloride, dimethyl-tin dichloride, dioctyltin dichloride, dilauryltin dichloride (Metallcxner Labs.), triphenyltin chloride, tri-n-butyltin chloride (Aldrich), tribenzyltin chloride, tricyclohexyltin bromide, tri-n-propyltin chloride, dibutyltin dibromde, diphenyltin dichloride (Metallomer Labs.), dextran (molecular weight 200,000-300,000 United States Biochemical Corp.), triethylenediamine (Eastman), triethylamine (Eastanan), piperdine (Matheson, Coleman and Bell), N,N-dimethylaniline (Fisher), Aniline (Baker), 4-dimethylamino-pyridine (gift from Reilly Tar and Chemical Corp.), 3,5-lutidine (Aldrich) and pyridine (Baker). 

Thallium(I) cyanide was introduced by Taylor and McKillop as a reagent. Aromatic and heteroaro-matic acyl cyanides are produced in go yield, whereas aliphatic acid halides lead under these conditions mainly to dimerization products. 18-Crown-6 is a good catalyst for the preparation of cyanoformate in methylene chloride with potassium cyanide and chloroformates. Similarly, tetraethylammonium cyanide gives cyanoformates in high yield under very mild conditions. Aroyl cyanides are generated easily by phase transfer catalysis with tetra-n-butylammonium bromide. Tri-n-butyltin cyanide proved successful only with aromatic acid halides, leading to dimerization products with aliphatic compounds. ... 

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