Tin-nitrogen heterocycles

Yoshida and coworkers described the control of free-radical reactivity during reduction by dynamic coordination pyridylethyl-substituted tin hydrides (123, 124) appear to selectively reduce alkyl iodides and bromides in preference to chlorides, as illustrated in equations 102 and 103805. Dumartin and his associates reported the immobilization of substrates required for the synthesis of 17a-(iodovinyl)estradiol through hydrostannylation with a polymer-supported tin hydride (equation 104)803. Baba and coworkers described the use of Bu2SnIH in the synthesis of nitrogen heterocycles (e.g. 125) (equation 105)804. 

Intramolecular aryl halide animations to form nitrogen heterocycles were included in the initial reports on tin-free aryl halide animations [80]. For example, the reactions in Eq. (6) occurred in greater than 80% yield. In this case, the halide could be iodide or bromide, and [Pd(PPh3)4] was a more effective catalyst than was Pd[P(o-C6H4Me)3]2Cl2. ... 

There is a comprehensive review of tin adducts with nitrogen heterocycles . ... 

Strecker reactions provide one of the most efficient methods for the synthesis of a-amino nitriles, which are useful intermediates in the synthesis of amino acids and nitrogen-containing heterocycles. Although classical Strecker reactions have some limitations, use of trimethylsilyl cyanide (TMSCN) as a cyano anion source provides promising and safer routes to these compounds.133-351 Consequently, we focused our attention on tributyltin cyanide (Bu3SnCN), because Bu3SnCN is stable in water and is also a potential cyano anion source. Indeed, the Strecker-type reactions of aldehydes, amines, and Bu3SnCN proceeded smoothly in water (Eq. 9).1361 It should be noted that no surfactants are required in this reaction. Furthermore, Complete recovery of the toxic tin compounds is also possible in the form of bis(tributyltin) oxide after the reaction is over. Since conversion of bis(tributyltin) oxide to tributyltin cyanide is known in the literature, this procedure provides a solution to the problem associated with toxicity of tin compounds. 

Phenyl ethylenesulfonate, 241 Tin(IV) chloride, 300 Containing one sulfur 2,4-Bis(4-me thoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide, 38 Titanium(IV) chloride-Zinc, 310 Other five-membered heterocycles Carbon dioxide, 65 Methanesulfonyl chloride, 176 Six-membered rings Containing one nitrogen—piperidines Dichlorotris(triphenylphosphine)-ruthenium(II), 107 Mercury(II) trifluoroacetate, 175 Tetrakis(triphenylphosphine)-palladium(O), 289... 

As with other nitrogen-containing heterocycles, TV-alkylation is a reaction of some interest. This is particularly true when the products are nucleosides. One interesting example of nucleoside formation arises from reaction of a suitable furo[3,4-J]pyrimidine (41) and l-O-acetyl-2,3,5-tribe nzoyl-/ -D-ribose the product formed seems to be solvent dependent. The N-l substituted nucleoside (42 R = tribenzoylribose) is formed in 81 % yield when the heterocycle and the protected sugar are treated with tin(IV) chloride in acetonitrile. However, use of 1,2-dichloroethane as solvent affords only 17% of this product together with 81% of the N-l,N-3 disubstituted product (Equation (10)) <83CPB3074>. 

Aziprotryne heterocyclic nitrogen, triazine Azocyclotin organo tin, triazole... 

The reader is encouraged to consult the excellent review by Veith concerning cyclic tin(II)-nitrogen compounds (107), which provides a complement to heterocycles containing organotin(IV). 

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