Imidazole -5-trifluoromethyl

Keywords Benzimidazole Fluorination Fluoroalkylation Imidazole Trifluoromethylation... 

Imidazole, 2-aryl-4-phenyl-5-trifluoromethyl-synthesis, 5, 483 Imidazole, azido-reactions, 5, 442 Imidazole, 2-azido-, 5, 415 cyclization, 6, 980 reactions, 5, 96 with sodium, 5, 442 tautomerism, 5, 371 Imidazole, benzoyl-IR spectra, 5, 30 Imidazole, 2-benzoyl-4-phenyl-... 

Fluorination of thiophene-2,5-dicarboxylic acitl with a sulfur tetrafluoritie-hydrogen fluoride mixture provides 2,5-bis(trifluoromethyl)thiophene in a 69% yield no fluorine addition to the thiophene ring occurs [229J. Also, imidazole mono- and dicarboxylic acids yield only the respective trifluo-romethyliinidazoles [230],... 

A valence bond isomer of pentakis-(trifluoromethyl)-l, 3-diazepine (44) was prepared from (43) (81TL1113) (44) can be transformed thermally or photochemically to a 2,4-diazabicyclo(3.2.0)hepta-2,6 diene (45), which was subsequently photolysed to an imidazole in an anionic process. Compound (45) is highly acidic arising out of the bishomoaromaticity of the anion and forms a salt with Et3N (81TL1369). 

Ethyl substitution at the imidazole 5-position (469) was found to increase potency over the unsubstituted analogue (468), while methyl substitution (470) had a slightly deleterious effect on binding (Table 6.41). Chloro (491), bromo (492), cyano (493) and fluoromethyl (494) substitution at this position were all well tolerated (Table 6.43). Introduction of a chloro-substituted pyridine (475) in place of the more usual / -chlorophenyl group (470) resulted in a slight loss of affinity for the CBi receptor, as did replacement of the p-chloro group of (470) with bromo (471), fluoro (472) and in particular, met-hoxy (473). Trifluoromethyl substitution (474) however, was well tolerated. 

For commonly encountered heterocycles, the chemical shifts of trifluo-romethyl substituents will depend somewhat upon where in the heterocycle they are located. Examples of trifluoromethyl derivatives for a number of common heterocycles, including pyridines, quinolines, pyrroles, indoles, thiophenes, benzothiophenes, furans, benzofurans, imidazoles, and uracils are given below. 

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

Displacement of a halogen atom of the imidazole ring of a tricyclic 5 6 5 angular system via nucleophilic attack at carbon has been used to incorporate amines, the trifluoromethyl group, or ethers as illustrated for the reaction of 69 with methoxide to give 70 (Equation 10) <2004BML1291>. However, the authors do not comment on the yields obtained in these reactions. 

Hutzler, J.M., Steenwyk, R.C., Smith, E.B., Walker, G.S. and Wienkers, L.C. (2004) Mechanism-based inactivation of cytochrome P450 2D6 by l-[(2-ethyl-4-methyl-1 H-imidazol-5-yl) methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine kinetic characterization and evidence for apoprotein adduction. Chemical Research in Toxicology, 17 (2), 174—184. 

Reaction of the imidazole (7-4) with the benzofuran derivative (6-7) leads to the displacement of the benzylic halogen and the formation of the alkylation product (8-1). Treatment of that intermediate with trifluoroacetic acid breaks open the urethane to afford the corresponding free amine. This is allowed to react with ttiflic anhydride to afford the trifluoromethyl sulfonamide (8-2). The ester group on the imdidazole is then saponified, and the newly formed acid is reacted with carbonyl diimidazole. Reaction with ammonia converts the activated carboxyl group to the amide. There is thus obtained the angiotensin antagonist saprisartan (8-3) [6]. 

A variety of imidazole-,113148 thiazole- and isothiazoleearboxylic acids149 are stable enough to react with a sulfur tetrafluoride/hydrogen fluoride system modest to excellent yields of the corresponding (trifluoromethyl)imidazoles, -thiazoles and -isothiazoles can be obtained (Table 5). 

Imidazole, 2,4,5-trichloro-1-methyl-chlorination, 5, 398 Imidazole, 2,4,5-trideutero-iodination, 5, 401 Imidazole, 1-trifluoroacetyl-reactions, 5, 451-452 Imidazole, 2-trifluoromethyl-hydrolysis, 5, 432 Imidazole, 2,4,5-triiodo-nitration, 5, 396 synthesis, 5, 400 Imidazole, 1,2,4-trimethyl-photolysis, 5, 377 rearrangement, 5, 378 Imidazole, 1,2,5-trimethyl-photochemical rearrangement, 5, 377 rearrangement, 5, 378 Imidazole, 1,4,5-trimethyl-bromination, 5, 399 3-oxide... 

Ring opening-ring closure sequences have been proposed to account for formation of 4-(trifhroromethyl)imidazoles on base-promoted trifluoromethyl elimination from 4,4-bis(trifhroromethyl)-5-hydroxyimidazoline.103... 

Evidence for the tetrahedral intermediate includes a Hammett p constant of+2.1 for the deacylation reaction of substituted benzoyl-chymotrypsins and the formation of tetrahedral complexes with many inhibitors, such as boronates, sulfonyl fluorides, peptide aldehydes, and peptidyl trifluoromethyl ketones. In these last the chemical shift of the imidazole proton is 18.9 ppm, indicating a good low-barrier H-bond, and the pJQ of the imidazolium is 12.1, indicating that it is stabilized by 7.3 kcal mol 1 compared to substrate-free chymotrypsin. The imidazole in effect is a much stronger base, facilitating proton removal from the serine. 

A, 1,1,1 -Tetrafluoro-/V- (trifluoromethyl)sulfonyl methanesulfonamide, see lV-Fluorobis(trifluoromethanesulfonyl)imide, 0640b 1.3a, 4,6a-Tetrahydro-lV,lV -dinitroimidazo[4,5-ii]imidazole-2,5-diamine, see Octahydro-2,5-bis(nitroimino)imidazo[4,5-(i]imidazole, 1511... 

Cycloaddition with activated alkenes Reaction between 3-substi-tuted imidazole 1-oxides 228 and 2,2-bis(trifluoromethyl)ethene-l,l-di-carbonitrile leads to 2-(l,3-dihydro-2H-imidazol-2-ylidene)malononitriles 304 (2006HCA1304). 

Chemical Name ( )-4-chloro-a,a,a,-trifluoro-./V-(l-iniidazol-l-yl-2-propoxyethylidene)-otolui-dine l-[l-[[4-chloro-2-(trifluoromethyl)phenyl]imino]-2-propoxyethyl]-l//-imidazole CAS Registry No 68694-11-1... 

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