T. Isida

Formation of organotin-nitrogen bonds IV. N-trialkyltin derivatives of 4-mono- or 4,5-disubstituted 1,2,3-triazoles, 3-phenyl-1,2,4-triazole, 3-phenylpyrazole and 4-phenylimidazole☆

Abstract N -(Trialkylstannyl)-4-mono- or 4,5-disubtituted 1,2,3-triazoles have been prepared by the 1,3-cycloaddition of tri-n-butyltin azide to alkynes and by the condensation of 1,2,3-triazoles with bis(tri-n-butyltin) oxide or trimethyltin hydroxide. The trialkyltin group has been shown to be attached to the 2-nitrogen of the 1,2,3-triazole ring. N -Tri-n-butyltin derivatives of 3-phenylpyrazole, 4-phenylimidazole and 3-phenyl-1,2,4-triazole have been prepared by the condensation of bis(tri-n-butyltin)oxide with the corresponding azoles, the tri-n-butyltin group becoming attached to the 1-nitrogen atom of the latter.

The reaction of optically active (1-methyl-2,2-diphenylcyclopropyl)trimethyltin with bromine or iodine

Abstract Reaction of an optically active (1-methyl-2,2-diphenylcyclopropyl)trimethyltin (I) with bromine (or iodine) afforded 1-bromo-(or iodo)-1-methyl-2,2-diphenylcyclopropane (II) with a small degree of retention of configuration. This is best interpreted in terms of radical mechanism for the cleavage of the cyclopropyl carbontin bond in (I) by bromine or iodine.

Formation of organotinnitrogen bonds : VI. The intermolecular association of 2-(tri-n-butylstannyl)-tetrazoles in solution☆

Abstract The intermolecular association of 2-(tri-n-butylstannyl)tetrazoles in benzene solution has been evaluated by the measurement of the apparent molecular weight. The degree of the association is highly dependent on the steric effect of the 5-substituent of the tetrazoles. Low temperature NMR spectra of CDCl 3 solutions of 2-(tri-n-butylstannyl)-5-phenyltetrazole and -5-( p -nitrophenyl)tetrazole displayed temperature- and concentration-dependencies. As the temperature decreases, the benzene and tetrazole rings become less coplanar. This may be attributed to the closer polymeric association of the 1-nitrogen to tin at low temperature. The intermolecular associated form of 2-(tri-n-butylstannyl)tetrazoles in less polar solvents such as benzene and chloroform is confirmed as a 1,3-structure (A).

Preparation and Thermal Decomposition of 1,4,5- and 1,3,5-Trimethyltetrazolium Iodides

1,4,5- and 1,3,5-Trimethyltetrazolium iodides were prepared by the reaction of methyl iodide with 1,5- and 2,5-dimethyltetrazoles, and the reaction of methyl iodide with 5-methyltetrazole. The latter method is more facile for the preparation of these iodides. Upon thermal decomposition of the 1,3,5-trimethyl salt at 130°C, the 1-methyl group was eliminated predominantly to yield 2,5-dimethyltetrazole. When the 1,4,5-trimethyl salt was decomposed at 270°C, a mixture of 1,5- and 2,5-dimethyltetrazole was obtained in 74% and 21% yields, respectively. For the formation of 2,5-dimethyltetrazole from the 1,4,5-trimethyl salt, there has been shown an intermolecular methylation scheme that the 1,4,5-trimethyl salt methylated 1,5-dimethyltetrazole being formed in situ to give the 1,3,5-trimethyl salt.

Hydrogen-Deuterium Exchange in 1,4,5- and 1,3,5-Trimethyltetrazolium Iodides

1,4,5- and 1,3,5-Trimethyltetrazolium iodides were prepared by the reaction of methyl iodide with 1,5- and 2,5-dimethyltetrazoles, and the reaction of methyl iodide with 5-methyltetrazole. The latter method is more facile for the preparation of these iodides. Upon thermal decomposition of the 1,3,5-trimethyl salt at 130°C, the 1-methyl group was eliminated predominantly to yield 2,5-dimethyltetrazole. When the 1,4,5-trimethyl salt was decomposed at 270°C, a mixture of 1,5- and 2,5-dimethyltetrazole was obtained in 74% and 21% yields, respectively. For the formation of 2,5-dimethyltetrazole from the 1,4,5-trimethyl salt, there has been shown an intermolecular methylation scheme that the 1,4,5-trimethyl salt methylated 1,5-dimethyltetrazole being formed in situ to give the 1,3,5-trimethyl salt.