Benzimidazole 5-trifluoromethyl

Examples providing fluorine chemical shift data for trifluoromethyl imidazoles and a benzimidazole bearing a trifluoromethyl group are given in Scheme 5.53. 

Photolytic. Irradiation of trifluralin in hexane by laboratory light produced a,a,a-trifluoro-2,6-dinitro-A-propyl-jo-toluidine and a,a,a-trifluoro-2,6-dinitro-p-toluidine. The sunlight irradiation of trifluralin in water yielded a,a,a-trifluoro-A, 7 -dipropyl-5-nitrotoluene-3,4-diamine, a,a,a-trifluoro-A/ ,A/ -dipropyltoluene-3,4,5-triamine, 2-ethyl-7-nitro-5-(trifluoromethyl)benzimidazole, 2,3-dihydroxy-2-ethyl-7-nitro-l-propyl-5-(trifluoromethyl)benzimidazoline, and 2-ethyl-7-nitro-5-(trifluoromethyl)benzimidazole. 2-Amino-6-nitro-a,a,a-trifluoro-p-toluidine and 2-ethyl-5-nitro-7-(trifluoromethyl)benzimidazole also were reported as major products under acidic and basic conditions, respectively (Crosby and Leitis, 1973). In a later study, Leitis and Crosby (1974) reported that trifluralin in aqueous solutions was very unstable to sunlight, especially in the presence of methanol. The photodecomposition of trifluralin involved oxidative TV-dealkylation, nitro reduction, and reductive cyclization. The principal photodecomposition products of trifluralin were 2-amino-6-nitro-a,a,a-trifluoro-jo-toluidine, 2-ethyl-7-nitro-5-(trifluoromethyl)benzimida-zole 3-oxide, 2,3-dihydroxy-2-ethyl-7-nitro-l-propyl-5-(trifluoromethyl)benzimidazole, and two azoxybenzenes. Under alkaline conditions, the principal photodecomposition product was 2-ethyl-7-nitro-5-(trifluoromethyl)-benzimidazole (Leitis and Crosby, 1974). 

When trifluralin was released in the atmosphere on a sunny day, it was rapidly converted to the photochemical 2,6-dinitro-7V-propyl-a,a,a-trifluoro-/ -toluidine. The estimated half-life is 20 min (Woodrow et ah, 1978). The vapor-phase photolysis of trifluralin was studied in the laboratory using a photoreactor, which simulated sunlight conditions (Soderquist et al., 1975). Vapor-phase photoproducts of trifluralin were identified as 2,6-dinitro-Wpropyl-a,a,a-trifluoro-p-toluidine, 2,6 dinitro-a,a,a-trifluoro-jo toluidine, 2-ethyT7-nitro-l-propyl-5-(trifluoromethyl)benzimidaz-ole, 2 ethyT7-nitro-5-(trifluoromethyl)benzimidazole, and four benzimidazole precursors, reported by Leitis and Crosby (1974). Similar photoproducts were also identified in air above both bare surface treated soil and soil incorporated fields (Soderquist et al., 1975). 

Dihydroxy-2-ethyl-7-nitro-l-propyl-5-(trifluoromethyl)benzimidazole, see Trifluralin... 

Ethyl-7-nitro-5-(trifluoromethyl)benzimidazole-3-oxide, see Trifluralin 5-Ethyl parathion, see Parathion 0,0-Ethyl-O-phosphorothioate, see Chlorpyrifos, Diazinon. Ronnel... 

Reddy, G.V., Rama Rao, V.V.V.N.S., Narsaiah, B. and Rao, P.S., A simple and efficient method for the synthesis of novel trifluoromethyl benzimidazoles under microwave irradiation conditions, Synth. Commun., 2002,32, 2467-2476. 

Reaction of recently synthesized 1 -al kvnyl />-( trifluoromethyl )phenyl]( tetrafluoro-borato)-X3-bromanes with 2-mercapto- benzimidazole or benzothiazole in dichloro-methane at 0°C under argon resulted in a domino Michael addition-carbene rearrangement-cyclization reaction to produce directly tricyclic heterocycles in high yields (Scheme 67).103... 

Preparation of 5-amino-l-(2-chlorophenyl)-7-(trifluoromethyl)-l,3-dihydro-2H-benzimidazol-2-one... 

Preparation of l-(2-chlorophenyl)-2-oxo-7-(trifluoromethyl)-2,3-dihydro-lH-benzimidazole-5-carbonitrile... 

Difluorobenzonitrile and methylthioglycolate cyclize to give 4-fluorobenzo[fe]thiophene [91JFC(54)104]. The reaction of trifluoromethyl-substituted 2,4-dinitrochloro- and 2,6-dinitrochlorobenzene with alkyl thi-oglycolates and amino acid esters at room temperature in the presence of triethylamine follows the same mechanistic concept to yield trifluoromethyl-substituted benzothiazole and benzimidazole derivatives [88JFC(38)327] (Scheme 25). 

Benzimidazoles, 2,3-dihydro-, by Nu addition at C-2, 56, 203 Benzimidazole, 2-fluoro-, 59, 272 Benzimidazole, 1-methyl-, ring expansion to chloroquinoxalines, 59, 305 Benzimidazole, l-methyl-2-(5 -methyl-2 -thienyl)-, bromination, 57, 319 Benzimidazole 3-oxides, chloro-deoxygenation, 59, 270 Benzimidazoles, 2-perfluoroalkyl-, 60, 25 Benzimidazoles, 2-(l-pyridinio)-, 60, 204 Benzimidazoles, 2-(2-pyridinioethyl)-, elimination reactions, 60, 246 Benzimidazoles, tetrafluoro-, 59, 14 Benzimidazole-2-carboxylic ester 3-oxide, 7-nitro-5-trifluoromethyl-, 60, 17 Benzimidazolium salts, l-amino-3-alkyl-, reaction with activated acetylenes, 56, 138... 

An interesting approach for the synthesis of some fused pyrimidines has been reported by Shaaban [102] via reaction of 4,4,4-trifluoro-l-(thien-2-yl)butane-1,3-dione in the presence of triethylorthoformate with 5-aminopyrazole or 1,2,4-aminotriazole or 2-aminobenzimidazole under microwave irradiation. The resulting trifluoromethyl derivatives of pyrazolo[l,5-a]pyrimidine 56, l,2,4-triazolo[l,5-a] pyrimidine 57 and pyrimido[l,2-a]benzimidazoles 58 were obtained in excellent yields and purity (Scheme 42). 

TRIFLUOROMETHYL)ANILINE see AID500 m-(TRIFLUOROMETHYL)ANILINE see AID500 3-(TRIFLUOROMETHYL)BENZENAMINE see AID500 (TRIFLUOROMETHYL)BENZENE see BDH500 2-TRIFLUOROMETHYL BENZIMIDAZOLE see TKB800... 

The reaction between o-phenylenediamine and an equimolar amount of an aromatic or heterocyclic aldehyde has been shown to proceed by initial formation of a monoanil (74). In the presence of oxidizing agents (e.g. nitrobenzene, which also acts as the solvent) this can form the 2-substituted benzimidazole. With two moles of aldehyde the bis-anil (75) forms, giving rise to a 1,2-disubstituted benzimidazole (Scheme 42). This aldehyde route to benzimidazoles is particularly suited to the synthesis of compounds with a heterocyclic group (e.g. 2-thienyl-, 2-pyridyl-) at C-2. Reaction of 2,2,4,4-tetrakis(trifluoromethyl)-l,3-dithietane with o-phenylenediamine gives 2,2-bis(trifluoromethyl)benzimidazoline (7430785). 

Fluoro-2-trifluoromethylthiazolo[3,2-a]benzimidazol-3(2//)-one (508 A = benzimidazole nucleus, R = F, R = CF3), on heating in alcohol even for a short period, undergoes alcoholysis to give ester 512. The electron-withdrawing nature of the fluorine and trifluoromethyl groups at... 

Although a number of such radical reactions are known, few promise much synthetic potential, Examples include the 2-phenylation of imidazole and benzimidazole by benzoyl peroxide, but both products are more readily obtained by other routes. Homolytic alkylations of imidazole and benzimidazole also occur at C-2, but usually give indifferent yields [10]. A potentially useful reaction is the synthesis of 2- and 4-trifluoromethylimidazoles from imidazoles and photochemically generated trifluoromethyl radicals. 1-Substituted imidazoles are largely substituted at C-5 in these reactions benzimidazole reacts initially at the 4-position [11-14]. 

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