4-Amino-1,2,3-triazoles structure

Triazoles and Benzotriazoles.—1,2,3-Triazoles. The X-ray structure of the amino-triazole ester (603) has been reported. " A new general synthesis of 1-alkyl-u/c-triazoles is exemplified by the reaction of the lithiated nitrosoamine LiCH2NMeNO with benzonitrile to yield (604). The bis-toluene-p-sulphonyl-hydrazone of benzil cyclises to the triazole (605) in in the presence of mercury(ii)... 

QM/MM calculations and experimental kinetic study have explored the effects of solvation on the transition states for reaction between nitromethane and formaldehyde and between nitropropane and benzaldehyde. Asymmetric reactions of nitromethane with various aldehydes have been promoted by Cu(II) coordinated with amino alcohols, 0 imidazolium/pyrrolidinium-tagged Indabox, and imidazolium-taggedbis(oxazoline)-based chiral ligands. The Henry reaction has also been promoted by Mn(OAc)2/Schiff bases bearing a triazole structure, with up to 99% yield, and by phosphonium ionic ligands MeP+(octyl)3 R0C02 without solvent. ... 

The 3-amino group brings a second nucleophilic center in these structures thus 2-imino-3-amino-4-methyl-4-thia201ine (409) reacts with methyl diloroformate to give the bicyclic compound (410) (Scheme 234). Other thiazolo-s-triazoles of the [3.2-l>] type have been obtained by... 

Similarly to aminoazoles, diaminoazoles prefer their amino forms 210 for 3,5-diaminopyrazole [76AHC(S1), p. 460 84CHEC-I(5)167 96CHEC-11(3)1] 211 for 3,5-diamino-l,2,4-triazole and 212 for 3,5-diaminoisothiazole [76AHC(S1), p. 460]. Ilie triamino structure 213 was proven by an X-ray crystallographic study of 4-aminoquinazine hydrobromide [73JCS(P2)lj. 

Fragmentary ultraviolet spectral data are available for 3-amino-1,2,4-triazole. Early chemical data on 3,5-diamino-2-phenyl-l,2,4-triazole were interpreted on the basis of the diimino structure 201, but ultraviolet spectral evidence was later stated to favor either structure 202 or 203. ... 

Diazotization of 5-amino[l, 2,3]triazole 692 afforded (88BSB179) triaz-olo[l, 5-i>][l, 2,4]triazine 694 as a result of a Dimroth rearrangement of the initially formed isomeric structure triazolo[5,l-c][l,2,4]triazine 693. Molecular structure of 694 was determined by single X-ray diffraction (Scheme 146). 

An interesting Mossbauer study has been reported on the dinuclear SCO complex [Fe2 (PMAT)2](BF4)4-DMF (PMAT 4-amino-3,5-bis [(2-pyridylmethyl) amino]methyl -4H-1,2,4-triazole), where thermal ST occurs from [HS-HS] to the stable endproduct [HS-LS] [32]. The molecular structure and magnetic behavior of this complex was reported earlier by Brooker et al. [33, 34] (Fig. 8.15). At ca. 225 K, the complex undergoes a sharp half ST from the HS state, T2, to a state containing 50% HS and 50% LS, Af, isomers. The single-crystal structural analysis... 

A comprehensive study into the structures and molecular properties of 3-amino-177-l,2,4-triazole 15, 4-amino-477-1,2,4-triazole 16, and 5-amino-177-l,2,4-triazole 17 has been undertaken using ab initio methods, both to predict and confirm data obtained from microwave spectroscopy of these compounds <2004JST(705)177>. 

The same type of ring-closure reaction that leads to the [3,2- ]-fused 50 can also result, in principle, in formation of a [3,4- ]-fused ring system (see Sections 11.16.5.2 and 11.16.7). This case has been found when an amino group was present in the triazole ring, and formation of 51 has been supported by X-ray diffraction. The crystalline structure... 

Several ring-closure reactions for [l,2,4]triazolo[3,4- ][l,3,4]thiadizines have been described, and all these procedures started from 3-mercapto-4-amino[l,2,4]triazole 135 (Scheme 26). A common structural feature of the reagents is the presence of the CH2X (X = halogen atom) moiety which allows the alkylation at the sulfur atom followed by a ring-closure reaction via an elimination step. Some typical ring closures are shown in Scheme 26. 

Analyses of the structures and properties of a large number of energetic materials reveal that a combination of amino and nitro groups in a molecule often leads to better thermal stability, lower sensitivity to shock and impact, and increased explosive performance because of an increase in crystal density. Such observations are attributed to both intermolecular and intramolecular hydrogen bonding interactions between adjacent amino and nitro groups. Some modern triazole-based explosives have been designed and synthesized with this in mind. 

Fe(abptrz)2(tcnq)2] is an iron(II) complex of the triazole 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole (abptrz) and the 7,7, 8,8 -tetracyanoquinodimethane (tcnq) radical anion whose structure, (132), Mossbauer and IR spectra, and magnetic behavior (thermally induced (280 K) spin crossover -S = 2 -S = 0) have been established. " ... 

One of the first mentions about reaction products with angular structure was published by Desenko and co-authors in [94]. It was shown that multicomponent treatment of 3-amino-l,2,4-triazole with two equivalents of cyclohexanone yielded spiroheterocycles 61 (Scheme 29). 

On the way to the investigation of the structure-activity relationship Huang et al. [138] performed the MCRs involving diverse-substituted 3-amino-l,2,4-triazoles,... 

Structures of guanazo- and pyroguanazoles, and reaction of dicyandiamide with 3-amino-5-substituted-4H- 1,2,4-triazoles)... 

PATO has also been synthesized by a Chinese team [68] by the condensation of tetryl with 3-amino-l,2,4-triazole and their data on its thermal stability is in agreement with American investigators [69]. Chinese researchers have also reported two nitro derivatives of PATO with the following structures based on IR and NMR [68]. 

Agrawal and co-workers have reported the synthesis of N,N -bis(l,2,4-triazol-3-yl)-4,4 -diamino-2,2, 3,3, 5,5, 6,6 -octanitroazobenzene (BTDAONAB) [Structure (2.39)] via nitration-oxidative coupling of 4-chloro-3,5-dinitroaniline followed by nucleophilic displacement of the chloro groups with 3-amino-l,2,4-triazole. BTDAONAB has the unique distinction of being the most thermally stable explosive reported so far (DTA exotherm 550 °C) as compared with well-known thermally stable explosives such as TATB (-360°C), TACOT (-410°C), NONA (-440-450°C) and PYX (-460 °C) [25]. 

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