Tetrazoles trifluoromethyl

In the course of studies on azide-tetrazole equilibria, some azido derivatives 73 of this ring system have been subjected to X-ray structure elucidation <2005JST(751)65>. These derivatives proved to be mainly planar and the least planar part of these molecules were the azide moieties. In both cases (72 R= H and Me), formation of hydrates were also observed. Crystallographic analysis of the trifluoromethyl compound was described by Lange et al. <1997APH299>, and structure elucidation of the nucleoside analogue 74 was reported by Stanovnik et al. <1998JHC513>. 

Chen and coworkers have developed two new phosphorescent blue emitters, which have two identical 2-(2,4-difluorophenyl)pyridine ligands and are derivatives of the Firpic compound, iridium(III) bis(4,6-difluorophenylpyridinato)-3-(trifluoromethyl)-5-(pyridin-2-yl)-1, 2,4-triazolate (Firtaz) and iridium(III) bis(4,6-difluorophenylpyridinato)-5-(pyridin-2-yl)-l//-tetrazolate (FirN4) (Scheme 3.90) [314]. Both these two blue emitters show a 10-nm blue-shift of the emission compared with Firpic. Unfortunately, the efficiency of such blue emitters is inferior to those of Firpic and Fir6. There is no lifetime data reported for such devices. 

Ethyl 2-cyano-2-(l-//-tetrazol-5-ylhydrazono)acetate, 2359 Ethyl iminioformate chloride, 1273 Ethylphenylthallium(lll) acetate perchlorate, 3302 Fluorobis(trifluoromethyl)phosphine oxide, 0645 Fluorodiiodomethane, 0373... 

Guanidine, melamine and 1//-tetrazol-5-amine react with sulfur tetrafluoride under forcing conditions to give low yields of (trifluoromethyl)iminosulfur difluoride (3).172... 

The bis(triphenylphosphine)azido complex undergoes some interesting addition reactions, with CFgCN to give a bis(trifluoromethyl-tetrazole) derivative, and with CSg to give a bis(thiotriazole) complex. The latter may be photolyzed in chloroform to [CuNCS(PPh3)2]2 S61). 

Heteroaryl Azides - 2-Pyridyl azides exist in equilibrium with bicyclic tetrazoles, with the latter predominating under normal conditions. A number of trifluoromethyl-substituted derivatives of tetrazoles, e.g. (53), have been synthe-... 

In contrast, there are many reports of trifluoromethyl- and other perfluoroalkyl-substituted tetrazoles prepared from fluorinated building blocks. For example, consistent with its high reactivity, trifluoroacetonitrile reacts exothermically with sodium azide to give sodium 5-trifluoromethyltetrazole 168 (Fig. 3.98). ... 

Trifluoromethyl-l-substituted tetrazoles in particular are employed in drug development. One of the many examples is the neurokinin-1 receptor antagonist 169 (GR205171) that is a potent and orally active antiemetic compound developed by Glaxo Wellcome. The substituted tetrazole moiety was prepared through the acetimidoyl chloride (Fig. 3.100). 

There are numerous reports in the patent literature of trifluoromethyl and other perfluoroalkyl-substituted tetrazoles, particularly with 1,5-subtitution, as pharmaceutical and agrochemical agents. Space does not allow a survey of this material here, but a detailed report of the application of fluorinated heterocyclic compounds in crop protection is given in another chapter of this book. ... 

Isomerization, A detailed investigation has been reported of catalysed and uncatalysed cis-trans and linkage isomerization reactions of [PdL2(tet)2] (L = a phosphine, tet = 5-methyl or 5-trifluoromethyl tetrazolate). This leads to the postulation of general mechanisms, involving five-co-ordinate transition states, that... 

RaP)2PdX2] (R3P = a large range of tertiary phosphines, X = 5-methyl- or 5-trifluoromethyl-tetrazolate) exhibits cis-trans and linkage isomerization in solution. The latter depends on which combination of N-1 and N-2 is bound, for example (65). It was found that linkage isomerization is faster than phosphine exchange in the... 

Abstract The chapter encompasses the synthesis, chemical transformations, properties, and applications of fluorinated monocyclic 1,2,3-, 1,2,4-tiiazoles and tetrazoles as well as their fused analogs. The heterocycles directly bonded with a fluorine atom (N-F or C-F isomers) as well as trifluoromethyl, perfluoroalkyl, per-fluoroaryl, SF5, NF2 groups and some other fluorinated fragments were considered. 

A widely used method of the preparation of versatile 1,2,3-triazoles and tetrazoles consists in the reaction of azides with fluorine-containing compounds with multiple bonds. For example, this approach afforded N-substituted 4(5)-fluoro-l,2,3-triazoles 27,28 by the 1,3-dipolar cycloaddition of perfluoropropadiene to phenyl azide [35], In the course of the reaction a mixture of regioisomeric 1,2,3-triazoles was formed l-phenyl-4-fluoro-5-trifluoromethyl-l,2,3-triazole 27 was considerably prevailed. On the contrary, the reaction of phenyl azide with the perfluoropropyne resulted in predominantly the isomer that was minor in the previous scheme. 

Some fluorine-containing tri- and tetrazoles behave as polidentate ligands and form stable complex compounds with various metal ions. The coordination compounds of Os(II), Ir(III), Ga(III), In(III), Ag(I), Sn(IV) with 5-pyridyl-2-yl-3-trifluoromethyl-1,2,4-triazole ligands we have already mentioned. 

The mechanism of activation of deoxyribonucleoside phosphoramidites by IH-tetrazole has recently attracted considerable attention. It has been argued that the protonation of the phosphoramidite function by l f-tet azole was rapid and followed by the reversible and slower formation of a phosphorotetrazolide intermediate (39). It is to be noted that relative to 5-(p-nitrophenyl)- IH-tetrazole (55), 1 -hydroxy-benzotriazole (24), / /-methylanilinium trifluoroacetate (40), iV-methyl-anilinium trichloroacetate (41), 5-trifluoromethyl-l//-tetrazole (23), A-methylimidazole hydrochloride (23), and )V-methylimidazole-trifluoromethane sulfonate (42), which have also been tested as activators, l/f-tetrazole still remained the most commonly used reagent for the activation of deoxyribonucleoside phosphoramidites. 

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