1.2.3- Triazole 5-phenyl-1 - -, ring

The effects of the 1,2,3-triazole and 1-amino-1,2,3-triazole heterocycles on the chemical shift of the carbon atoms in the phenyl ring of compounds (40) and (41) (X = H) are compared with the value for benzene. With regard to the effects of substituent X para and meta) on the 1,2,3-triazole carbons, C(4) is deshielded by electron-withdrawing groups, whereas C(5) is shielded. Reasonable correlations with Hammett a values are observed for the chemical shifts of both C(4) and C(5) of (41) <86MRC53>. The chemical shifts of C(4) and C(5) in 5-amino-l-aryl-l,2,3-triazoles are shifted upheld by 2-5 ppm compared with the corresponding 5-anilino-1,2,3-triazoles. In 5-anilino-... 

In the reaction of nitrile compounds with aryl azides bearing a carboxyl424 or nitrile423 function in the ortho position, fused triazoles are formed by further reaction of the 5-amino group with the ortho substituent on the 1-phenyl ring. Whereas a-cyanomethylene phosphonate gives the expected... 

The amination of 5-phenyl-l,5-dihydro[l,2,3]triazolo[4,5- /]-l,2,3-triazole (31) with o-(mesityl-sulfonyl)hydroxylamine afforded two V-aminated products distinguishable on the basis of their l3C NMR spectra (Equation (1)). The major product (46%), showed one carbon signal other than those from the phenyl ring and was therefore assigned as the symmetrical 2-amino derivative (32). The minor product showed two l3C signals in addition to those from the phenyl ring and was believed to be represented by structure (33) or (34) (33) is the preferred isomer on the basis of the similarity of its NMR spectrum to that of known l-acetyl-5-phenyltriazolotriazole. 

Alkenyl- and alkynyl-triazoles have received little attention. By analogy with the behaviour of other azoles they are expected to polymerize but to be less reactive in addition reactions than alkenes or alkynes. Although the most promising polymers derived from triazoles are obtained by different methods (see Section 4.12.5.2.3), some information is available on potentially polymerizable vinyltriazole (63MI4120i). The styryltriazole (134) could be oxidized to 3-methyl-l-phenyl-l,2,4-triazole, i.e. without affecting either the triazole or iV-phenyl ring, but hydroxylation of the alkene chain failed (s4JCS4256). 

Benzylidenecyclopropane, however, reacted with 4-phenyl-4/f-l,2,4-triazole-3,5-dione to give a 1 2 cycloadduct which can be rationalized by a [4 + 2] cycloaddition of the N-N double bond across the diene formed by the exocyclic C-C bond and a C-C bond of the phenyl ring, followed by a Diels-Alder reaction of the cyclohexadiene structure. 

V an Gestel etal. 980) prepared a series of substituted 1 -(2-phenyI-1,3-dioxolan-2-yl-methyl)-1,2,4-triazoles (60), ana evaluated them in the greenhouse for fungicidal activity. Compounds with 2,4-dichloro substitution on the phenyl ring and with a lower alkyl side chain on the dioxolane ring were found most promising for the control of powdery mildew on gherkins and barley, and for the control of bean rust. 

B enzyne and Cyclobutadlene Stereoelectronlc Activation - The catalytic interaction of cytochrome P-450 with 1-aminobenzotriazole (2), a compound that releases benzyne when chemically oxidized, results in time-dependent enzyme inactivation. 2,63 An unusual prosthetic heme adduct is formed in which two vicinal nitrogens of protoporphyrin IX are bridged by an ortho-substituted phenyl ring. The Inactivation reaction occurs even when substituents are placed on the exocyclic amino group of 1-amlnobenzo-triazole, although enzyme inactivation by substituted analogues has not been well characterized. The catalytic role of the enzyme and the structure of the heme adduct indicate that inactivation follows oxidative release of benzyne or a benzyne-like species within the active site of the enzyme. 

Figure 4-2 Chemical shifts of the itraconazole hydrogens of the piperazine ring a, the phenyl rings attached to the piperazine b, the triazole ring c and the methylene groups rf as a function of the number of DCl added.

An infinite polymer chain would require the integrals of the phenyl ring proton and the triazole proton to be the same. In the particular case shown in Fig. 1.46 the ratio is 1 i 0.9 which is converted using Carothers equation to give a... 

When either pure rotamer was heated in diphenylether at 200°C they reverted to a mixture of rotamers, as determined by the nmr spectra of the mixture. Computer modeling of 5 and 6 further suggested that the rotation about the triazole-phenyl bond could be hindered by the bulky groups in the 2-and 6-posidons on the phenyl ring. 

In contrast to Ru-24, the reaction between [RUCI2 (p-cymene)]2 as a precursor and an NHC carbene of 1,3,4-triphenyl-triazol-5-ylidene resulted in ortlio-metallation of the phenyl ring in position 1 to form Ru-32.Although the controllability was lower than Ru-24, Ru-32 could polymerize MMA and styrene derivatives (Mw/Mn 1.5). By using other ligands, the p-cymene complexes with a series of NHC ligands were successfully synthesized and used for the metal-catalyzed... 

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