Tri-n-butyl tin

The synthesis of the key intermediate aldehyde 68 is outlined in Schemes 19-21. The two hydroxyls of butyne-l,4-diol (74, Scheme 19), a cheap intermediate in the industrial synthesis of THF, can be protected as 4-methoxybenzyl (PMB) ethers in 94% yield. The triple bond is then m-hydrostannylated with tri-n-butyl-tin hydride and a catalytic amount of Pd(PPh3)2Cl238 to give the vinylstannane 76 in 98 % yield. Note that the stereospecific nature of the m-hydrostannylation absolutely guarantees the correct relative stereochemistry of C-3 and C-4 in the natural product. The other partner for the Stille coupling, vinyl iodide 78, is prepared by... 

The photoreduction of cyclobutanone, cyclopentanone, and cyclohexanone by tri-n-butyl tin hydride was reported by Turro and McDaniel.<83c> Quantum yields for the formation of the corresponding alcohols were 0.01, 0.31, and 0.82, respectively. Although the results for cyclopentanone and cyclohexanone quenching were not clear-cut (deviations from linearity of the Stem-Volmer plots were noted at quencher concentrations >0.6 M), all three ketone photoreductions were quenched by 1,3-pentadiene, again indicating that triplets are involved in the photoreduction. 

Tri(n-butyl)tin iodide is also an effective catalyst and its starting materials are available but TOT was selected due to its lower volatility. The octyltin compounds are also generally much less toxic than their butyltin counterparts (15). 

For example, the toxic organotin compound, tri-n-butyl tin, damages the endoplasmic reticulum and interacts with thiols in the Ca2+ pump such that the intracellular Ca2+ concentration rises to 500 to 600 pM. This is shown in Figure 6.12. 

Tri-n-butyl-tin(IV) fluoride, cetyltrimethylammoniumbromide, cationic, anionic, and non-ionic surfactants... 

Micellar systems (i.e.,. Shenoy 1984 Ohlendorf Brunn) as well as other colloidal systems (polyphosphates (Hunston), tri-n-butyl-tin-fluoride, e.g. Dunn Evans) come under the heading surfactants . It is necessary to differentiate soaps into anionic, cationic, and non-ionic types. Among the anionic types one can find, for instance, alkali metals and ammonium salts consisting of various fatty acids, which were... 

Dunn P, Oldfield D (1970) Tri-n-butyl-tin-fluoride. A novel coordination polymer in solution J Macromol Sci A4 1157... 

Methoxyethyl hemiacetals, 532 2-Methoxy-4-furyllithium, 325 (Methoxymethoxy)butene-2-yl(tri-n-butyl)tin,... 

Goh CL. 1985. Irritant dermatitis from tri-n-butyl tin oxide in paint. Contact Dermatitis 12 161-163. 

Pelikan Z, Cerny E. 1968. [The toxic effect of tri-n-butyl-tin compounds on white mice.] Arch Toxikol 23 283-292. (German)... 

Valkirs et al. [755,756] compared two methods for the determination of pg L 1 levels of dialkyltin and tributyltin species in marine and estuarine waters. The two methods studied were hydride generation followed by atomic absorption spectrometry and gas chromatography with flame photometric detection. Good agreement was obtained between the results of the two methods. Down to 0.0 lmg kg 1 of butyltin compounds, including tri- -butyl tin and tri-n-butyl tin oxide, could be detected. 

Iodoacetoxy(tri-n-butyl)tin, ICH,COOSnBu, (1) The reagent is prepared by reaction of iodoacetic acid with bis(tri-/j-butyl)tin oxide. The Tannyl ester CH,CHlCOOSnBu, (2) is prepared in the same way,... 

Some other interesting copolymers having properties of PVC thermal stabUizers, like poly[Af-(a-benzothiazolonylmethyl)methacrylate-co-methyl methacrylate] [45], of flame retardants like a terpolymer of styrene, acrylonitrile and a polymerizable perbrominated phenol [76] or poly[4-methacryloyloxy-2,3,5,6-tetrabromobenzyldi-phenyl phosphonate-co-methyl methacrylate] [104] (93), bioddes, mostly copolymers of monomers containing tris(n-butyl tin) or triphenyl tin moieties and alkyl acrylates, methacrylates, vinyl acetate, acrylonitrile, styrene or A-vinylpyrrolidone [105], e.g. a terpolymer of styrene, MMA and tri(n-butyl tin) itaconate [106] (94),... 

The in vivo anti-proliferative and anti-tumor activity of di-n-butyl and tri-n-butyl tin species towards Ehrlich ascites tumor IMG carcinoma, P388, and Sarcoma 180 has been reported. The cellular mechanism of the anti-proliferative activities reveals that the di-n-butyl- and tri-n-butyl-tin species selectively accumulate near to the nucleus, golgi apparatus, and endoplasmic reticulum in the cell and then destroy the structure of Golgi apparatus and endoplasmic reticulum, inhibiting the ceramide metabolism function, inositol triphosphate (IP3)-induced intracellular Ca + mobilization, and finally stopping the membrane-mediated signal transduction leading to DNA synthesis.44... 

Preliminary work with tri-n-butyl tin hydride and other reducing reagents has demonstrated that the addition product can be readily converted to the a,a-difluoroester. 

Essentially complete reductive dechlorination of the precursor poly(chlorofluoroethylene)s to PVF was achieved after 24 h at 60"C in tetrahydrofuran with a molar excess of tri(n-butyl)tin hydride and 1 mol% of azo6i s(isobutyronitrile) (11). The reaction mixture was homogeneous until dechlorination was almost complete, after which the mixture turned cloudy owing to the insolubility of PVF. 

The second Matsuo synthesis (233) was initiated with methyl 3-(2,2-dimethoxyethyl)-4-methyl-4-pentenoate (357) prepared (234) from carvone (239). Hydrolysis with lithium hydroxide followed by iodolactonization (I2-KI-NaHC03) and reduction with tri-n-butyl tin hydride in the presence of azobisisobutyronitrile in benzene under reflux afforded 358. The carbo-methoxy group was introduced with methyl chloroformate and LDA in quantitative yield, and reductive animation of 359 with methylamine and sodium cyanoborohydride gave the lactone 360. Heating of 360 with 10% Pd/C in decalin gave cerpegin (118) in 81% yield (Scheme 42) (233). 

Figure 1. 25-MHz 13C NMR spectrum of FVC reduced with tri-n-butyl-tin hydride (see text for details)...

---