1.2.3- Triazole, 4,5-dicyano

Bis(3,4-diethyl-2-pyrrolylmethyl)-3,4-dietliyl-l//-pyrrole (2), prepared in situ from the di-t-butylester of the 5,5 -dicarboxylic acid (/), reacts with 4//-1,2,4-triazole-3,5-dialdehyde (3) in di-chloromethane in the presence of trifluoroacetic acid and 2,3-dichloro-5,6-dicyano-/)-benzoquino-ne as an oxidation reagent. Dark blue crystals are obtained after chromatographic purification. The dark violet chloroform solution fluoresces purple at 360 nm and gives the NMR experiments 39. Which compound and which tautomer of it has been formed ... 

Reactivity of azides towards acetylenedicarboxylates is very dependent on their electron density (energy HOMO). Thus, strongly electron-deficient 3,5-dicyano-2,4,6-triazidopyridine 1039 reacts slowly with dimethyl acetylenedicarboxylate to give triazole derivative 1038 in 34% yield with most of the starting material recovered unchanged. Under comparable conditions, less electron-deficient 3,5-dichloro-2,4,6-triazidopyridine 1040 reacts with dimethyl acetylenedicarboxylate to provide 2,6-bis(l,2,3-triazol-lyl)pyridine derivative 1041 in 75% yield (Scheme 171) <2001CHE861>. 

The reaction of compound 376 with hydrazine gives product 377 that has been transformed into similar triazoles 378, after reaction with carbon disulfide in the presence of alcoholic potassium hydroxide, benzoic acid in the presence of phosphoms oxychloride, or 3-[bis-(methylthiomethylene)]pentan-2,4-dione and l,l-dicyano-2,2-dimethylthioethylene, in refluxing -butanol (Scheme 40) (Table 55) <2000FES641>. 

Lithium Salts Based on Heterocyclic Anions. Lithium salts based on organic anions where the formal charge is delocalized throughout substituted heterocyclic moieties were also reported sporadically, which included, for example, lithium 4,5-dicyano-l,2,3-triazolate ° and lithium bis(trifluoro-borane)imidazolide (Lild). ° The former was developed as a salt to be used for polymer electrolytes such as PEO, and no detailed data with respect to electrochemistry were provided, while the latter, which could be viewed as a Lewis acid—base adduct between LiBp4 and a weak organic base, was intended for lithium ion applications (Table 13). 

By Bing Closure of x-Aminodiazonium Salts This synthetic method is widely used for benzotriazole derivatives but is of very limited use for monocyclic triazoles. 4,6-Dicyano-v-triazole has been prepared by this method. The method has also been applied to some a-aminoamides and amidines, but is not successful in every... 

A thermally induced rearrangement of arylhydrazones of furoxan-3-carbonyl compounds into 2-aryl-5-[(hydroximino)arylmethyl]-2//-l,2,3-triazole 1-oxides has been observed for the first time.156 2-(2,2-Dicyano-l-hydroxyethenyl)-l-methylpyrroles (192) are readily rearranged to their 3-isomers (193) in nearly quantitative yield when heated to 75-142 °C. The inter- or intra-molecular auto-protonation of a pyrrole ring... 

Syntheses of fused mesoionic heterocycles such as [l,2,3]triazolo[l,5-a]-quinoline, -quinazoline, -quinoxaline, and -benzotriazine derivatives have been described <02T3185>. Cyclizations of alkyl 2-benzoylamino-(4,5-dicyano-1 //-1,2,3-triazol-1 -yl)propenoates gave [1,2,3]triazolo[l, 5-a]pyrazines <02H(56)353>. Reaction of triethyl N-( 1 -ethy 1-2-methy 1-4-nitro-l//-imidazol-5-yl)phosphorimidate with aryl isocyanates provided a route to 2-aryI-2//,4//-imidazo[4,5-fif][l,2,3]triazoles <02JCS(P 1)1968>. 2-(A,A-Diphenylamino)-4-hydrazino-6-... 

A novel approach to l,2,3-triazolo[l,5-a]pyrazines involving the cyclization of (4,5-dicyano-l,2,3-triazol-l-yl)propenoates has been reported <02H353>. The synthesis of 1,2,3-triazolo[l,5-a]pyrazinium-3-olate has been described <02KGS1302>. The synthesis of new fluorine containing triazolo and tetrazolopyrimidines has been reported <02S901>. 

Most derivatives with a ring NH are weak acids (S8JOCl916), an exception being 4,5-dicyano-1,2,3-triazole (42MI41100) in which resonance stabilization of the corresponding anion plays a certain role. Benzotriazole shows an increased acidity after chlorine is substituted in the benzene ring (5UA4360, SSJASIOS). 

Amino-2-phenyl-l, 2,3,5-tetrazin-6(3//)-one (8) has been obtained by first oxidizing 2-phenyl-2H-, 2,3-triazole-4,5-diamine (6) with lead(IV) acetate to get l,3-dicyano-2-phenyltriazene (7) and then by irradiating 7 in methanol with a medium-pressure mercury lamp for 7.5 minutes.5... 

The lithium salt with the 4,5-dicyano-l,2,3-triazolate anion (DCTA-) (also known as 1,2,3-triazole-4,5-dicarbonitrile (TADC-)) (Fig. 1.38p) was first studied by Michot in 1995 [701] and reported in two publications in 2003 [664,665]. Little has been reported regarding the properties of the lithium salt. Alkali and alkali earth salts with the DCTA anion have also been prepared [666,667]. The thermal stability of these salts was found to be excellent (>350 °C) [668]. hi general, triazole salts are known to be energetic. The alkali metal salts, however, were found to have low sensitivity towards impact, friction, electrostatic discharge, and fast heating [668]. The acid with the related pyrazole-3,4,5-tricarbonitrile anion (PATC-) (Fig. 1.38q) was first reported in 1962 [669], but the lithium salt has not been investigated extensively as an electrolyte salt [661, 670,671]. Similarly, the acid with the tetracyano-pyrrolide anion (TCP ) (Fig. 1.38r) was also reported in 1962 [672] and the sodium salt with this anion has been prepared [674]. Trifluoromethane-substituted versions of the C5(CN)5 and TCP" anions have also been reported (Fig. 1.38v, w) [688-692], but the lithium salt has only been reported for LiC5(CF3)5 (Fig. 1.39k) [692]. 

M. J. Crawford, K. Karaghiosoff, T. M. Klapotke, E A. Martin, Inoig. Chem. 2009, 48, 1731-1743. Synthesis and characterization of 4,5-dicyano-2H-l,2,3-triazole and its sodium, ammonium, and guanidinium salts. 

Lithium dicyano- 1,2,3-triazolate was reported as a useful electrolyte (38) [45]. 1-Butyl-3-methylimidazoliiun 3,5-dinitro-l,2,4-triazolate (39) (Fig. 2) (m.p. 32 °C, rmaterial Some novel ionic liquids made up of azolium cations and anions were also reported. These salts are 1-ethyl-3-methyUmidazohum 1,2,4-triazolate (40) (Tg - 76 °C, T 207 °C, 7] 60.2 cP at 25 "C) and tetrazolate (41) (Tg -89°C, t] 42.5 cP at 25 °C) (Fig. 2). Both 40 and 41 were prepared by the coupUng reactions of 1-ethyl-3-methylimidazolium hydroxide with triazole or tetrazole, respectively [50]. 

Subbaraman R, Ghassemi H, Zawodzinski TA Jr (2007) 4,5-Dicyano-lH-[l,2,3]-triazole as a proton transport facilitator for polymer electrolyte membrane fuel cells. J Am Chem Soc 129 2238-2239... 

In a very unique approach cyano substituted triazolate based ionic liquids were prep>ared by exchanging the anions in common ionic liquids such as [emim][l], [empyrr][I] or [epy][T with silver 4,5-dicyano-triazolate in water. Here the triazolate ring serves as a counter-anion with delocalized negative charge, and results in a ditninished cation-anion interaction due to its decreased charge density. Hence, there is a decrease in the viscosity of the resulting ionic liquids as compared to those with iodide counter-ions (Kitaoka, Nobuoka et al. 2010). 

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