Trimethyltin hydroxide

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. 

Elaboration of triol 88b to bryostatin 7 requires chemoselective hydrolysis of the Cl methyl ester in the presence of the C7 and C20 acetates, macrolide formation, installation of the C13 and C21 methyl enoates, and, finally, global deprotection. The sequencing of these transformations is critical, as attempts to introduce the C21 methyl enoate to form the fully functionalized C-ring pyran in advance of macrolide formation resulted in lactonization onto the C23 hydroxyl. In the event, trimethyltin hydroxide promoted hydrolysis [73] of the Cl carboxylate of triol 88b, and subsequent trie thy lsilylation of the C3 and C26 hydroxyls each occurs in a selective fashion, thus providing the seco-acid 89. Yamaguchi macrolacto-nization [39] proceeds uneventfully to provide the macrolide 67 in 66 % yield (Scheme 5.14). 

The triorganotin oxides and hydroxides are relatively straightforward. The complete structure of trimethyltin hydroxide has not yet been determined, but exposure of a solution of trimethyltin chloride to moisture gives the half-hydrolysis product Me3SnCbMe3Sn0H H20, in which trigonal-planar Me3Sn units are alternately bridged by Cl and OH, with rSnO = 212.5(2) and 212.1(2) pm, and rSnCl = 290.7(3) and 289.2(3) pm (Equation (132)).353... 

Coupling of 69 with methyl 4-hydroxyphenoxyacetate 70 was carried out in the presence of imidazole and confirmed by gel-phase 13C NMR of PSDES resin 71. The hydrolysis of resin-bound ester was efficiently achieved using trimethyltin hydroxide (TMTOH) [110-114] to give the corresponding immobilized carboxylic acid 72. For the key Staudinger reaction, activation of the carboxylic acid 72 by Mukaiyama s reagent 74 was employed (Scheme 20) [115-117]. The m-p-lactam 16 was obtained in a 12-14% isolated yield. 

Trimethyltin hydroxide and isothiocyanate, which are also self-associated polymers in the solid state, (58, 59) show rather smaller... 

Tin compounds have great affinity to sulfur. To convert the triorganotin compounds into inorganic tin compounds of low toxicity, the degradation of bis(tri- -butyltin) oxide, trimethyltin hydroxide, allyltri- -butyltin, tin... 

The principal exception to this pattern of behaviour is trimethyltin hydroxide [v(OH) 3620, 8(OH) 920 cm-1] which sublimes unchanged above 80 °C it can be dehydrated with sodium in benzene13 or with calcium hydride14 to give the oxide [vas(SnOSn) 740 cm4], but this fumes in air as it is hydrolysed back to the hydroxide. 

Thus, in solution, trimethyltin hydroxide exists as a hydroxide-bridged dimer (12-1). A complete crystal structure has not been reported, but it is clear that it is a hydroxide-bridged polymer.24-25... 

ORGANOTIN COMPOUNDS examples include trimethyltin acetate (1118-14-5) trimethyltin cyanate (73940-86-0) trimethyltin hydroxide (56-24-6) trimethyltin iodide (811-73-4) trimethyltin isothiocyanate (15597-43-0) trimethyltin sulfate (63869-87-4) trimethyltin thiocyanate (4638-25-9). See trimethyltin chloride. 

Dichlorobis(l-methyltetrazole) zinc(II) has been reported and its structure determined.111 The geometry around the zinc atom was that of a distorted tetrahedron. The tetrazoles were monodentate and again coordinated by a charge-transfer o-bond between the 4-N atom and the Zn which was coplanar with the ring.111 Cycloaddition of trialkyltin azides to nitriles or treatment of S-substituted tetrazoles with bis(tri-n-butyltin) oxide or trimethyltin hydroxide gave 2-jV-trialkyltin-5-substituted tetrazoles (67).112,113 The (tri-/i-butylstannyl)derivatives (68)... 

The structure of the simplest organotin hydroxide, trimethyltin hydroxide, MesSnOH, has not been fully characterized although it has been subjected to an... 

Methyltin trichloride, dimethyltin dichloride, and trimethyltin hydroxide or chloride were obtained from Research Organic/Inorganic Chemical Corporation (Sun Valley, Calif.) for use as the organotin standards. Stock solutions from 500 to 1000 parts per million in 95% ethanol were prepared and proved to be stable for four to five weeks. Serial dilutions, usually 1 100 of the stock solutions, were made fresh daily in deionized water when calibration was needed. Both the inorganic and methyltin standards were delivered with 10 yl size syringes. 

Method (1) had to be applied when no organotin oxide or hydroxide, but only the halide was available, and also in the case of benzpyrazole. All trimethyltin derivatives were prepared by this route, because at the time no suitable method was known for the preparation of trimethyltin hydroxide. A convenient method of preparation of this compound has recently been found 101). 

Trimethyltin hydroxide is an example of a well-characterized organotin hydroxide . In the crystal it has the chain structure illustrated in Fig. 8 (a). In non-polar solvents a dimeric species (CH3)3SnOH 2 is present and is believed to have the dihydroxo-bridged structure of Fig. 8 (b). 

The organotiji(IV) carboxylates are of particular interest in that they appear to exist in more than one form. When trimethyltin hydroxide reacts with, for example, formic and acetic acids, the products are the very insoluble (CH3)3SnOOCH and (CH3)3SnOOCH3. 

If trimethyltin hydride is left exposed to the air, crystals of trimethyltin hydroxide begin to appear after several hours, and continue to appear for several days until the oxidation is complete. Oxide begins to appear somewhat sooner in the case of a dihydride, presumably because of its very low solubility in the hydride. Because of this susceptibility to oxidation, operations involving the hydrides are normally carried out in an inert atmosphere. 

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