Imidazole methyl

Gas-phase pK values for azoles are unavailable except for imidazole and 1-methyl-imidazole. Imidazole is ca. 75kJmor more basic than ammonia, i.e. approximately the same as pyridine 1-methylimidazole is about 29kJmor more basic than imidazole (82PC40200). 

Annular nitrogen atoms can form hydrogen bonds, and if the azole contains an NH group, association occurs. Imidazole (84) shows a cryoscopic molecular weight in benzene 20 times that expected. Its boiling point is 256 °C, which is higher than that of 1-methyl-imidazole (198 °C). 

Titrimetric analysis is a classical method for generating concentration-time data, especially in second-order reactions. We illustrate with data on the acetylation of isopropanol (reactant B) by acetic anhydride (reactant A), catalyzed by A-methyl-imidazole. The kinetics were followed by hydrolyzing 5.0-ml samples at known times and titrating with standard base. A blank is carried out with the reagents but no alcohol. The reaction is... 

One such agent is synthesized from 2-methyl imidazole by reaction with epichlorohydrin under acidic conditions. This produces the antiprotozoal agent ornidazole (26). ... 

N,N -dimethyloxaldiamide is reacted with PCI5 to give 4-chloro-1-methyl imidazole. This is nitrated with HNO3 to give 5-nitro-1-methyl-4-chloroimidazole. Then, a mixture of 4.6 grams of anhydrous 6-mercaptopurine, 5 grams of 1-methyl-4-chloro-5-nitroimidazole and 2.5 grams of anhydrous sodium acetate in 100 ml of dry dimethyl sulfoxide was heated at 100°C for 7 hours. 

The diglycidyl ether (DGEBA) and the polyglycidyl compound (PGCBA) were mixed and heated to about 120 °C. The stoichiometric amount of bisphenol A was dissolved in the resin and, after cooling to about 60 °C, 0,1% by weight of 2-ethyl-4-methyl-imidazol was added to the mixture. The well stirred composition was degassed in a vacuum oven in order to remove trapped air. Afterwards, the reactive mixture was poured into preheated moulds and cured for two hours at 140 °C followed by two hours at 180 °C. 

Flooding. An iron-phthaloc/anine complex reacts with carbon monoxide to liberate methyl imidazole 26... 

H-Purin und 6-Amino-purin (unter Ammoniak-Abspaltung) liefern in waBrigen Puf-ferlosungen an Quecksilber l,2,3,6-Tetrahydro-9H-purin, das zu 5-Amino-4-(hydroxy-methylamino-methyl)-imidazol hydrolysiert werden kann2. 

Because silylation with HMDS 2/TCS 14 in acetonitrile at ambient temperature converts the unreactive a-chloroketone moiety of 743 into an /Z-mixture of reactive alkyl 4-chloro-3-trimethylsilyloxycrotonates 746a, b [230, 231] which can be isolated and distilled, if humidity is excluded, silylation of 743a, b in the presence of ami dine salts such as 745 gives the desired ethyl or methyl imidazole(4,5)-acetates 748a, b via IMz and 747b. The reaction of formamidine acetate with 746a,b affords 745 (with R=H) in up to 70% yield [232, 233] (Scheme 5.79). As side reactions one must, e.g., take into account the reaction of 746 with ammonia to give 755 which subsequently dimerizes to the pyrazine 756, as discussed in Section 5.5.3. 

Cimetidine and other imidazole-containing H2 receptor antagonists scavenge hydroxyl radicals at a frster rate than mannitol. This activity was attributed to the methyl imidazole moiety rather than the guanidine of cimetidine (Ching etal., 1993). 

In the reaction of an aminoalcohol with a methyl imidazole-AT-carboxylate or tert-butyl imidazole-AT-peroxycarboxylate, selective acylation of the amino function can be achieved11903 to give the carbamate and peroxycarbamate, respectively, the hydroxy groups of which can be further acylated ... 

Upon recrystallization, [Ni(tpzlmtacn)]2+ affords [Ni(L)(MeCN)]2+ (L = l,4-bis(pyrazol-l-ylmethyl)-l,4,7-triazacyclononane) via a N-dealkylation reaction and loss of a pendent arm.1420 More rational routes to Ni complexes of tacn ligands with only one or two pendent arms have been developed.1431,1432 In [Ni(L)(X) ]x (e.g., L= l-(3-aminopropyl)-l,4,7-triazacyclononane (n = 2) or l-(l-methylimidazol-2-ylmethyl)-l,4,7-triazacyclononane (n = 2) or l,4-bis(l-methyl-imidazol-2-ylmethyl)-l,4,7-triazacyclononane (n = 1), the coordination sphere is completed by additional ligands that bind either terminal (X = C1 , H20) or bridge two metal ions (X = N3 , OH, oxalate). The Ni11 complex of l,4-bis(2-pyridylmethyl)-l,4,7-triazacyclononane has been shown to be extremely inert to ligand dissociation in aqueous solution.1433 In (562), the tacn ligand provides a single bidentate arm.1434... 

Bouwman synthesized complexes of tridentate ligand A,A-bis(2-ethyl-5-methyl-imidazol-4-ylmethyl)aminopropane (5). [Zn L2]2+ complexes were synthesized with IR spectroscopic data indicating octahedral coordination.118... 

Computations performed on an N-methylated imidazole showed that the presence of the methyl group increases the proton affinity of the other nitrogen. In contrast, a peptide substituent at a carbon adjacent to the nitrogen decreases its proton affinity. This can be explained by the conjugation stabilization of the peptide-substituted neutral form, which is absent in the protonated form. This result seems to indicate that heteroatomic rings linked by... 

Bis-imidoyl chloride 187 reacts with A -methyl imidazole 188 to give bis-cationic diimidazo[l,2- 2, T-c]pyrazine 189 (Equation 46) <2006T731>. The charges are believed to be delocalized over the ring system. 

Treatment of (tht)AuC6F5 with l-methyl-imidazol-2-yl-lithium gives an ionic product which can be converted into the neutral carbene complex upon A-methylation with Mel (Equation (29)).146... 

Compounds of the same type are accessible by reaction of l-methyl-imidazol-2-yl lithium with components XAu(tht) (X = CN, C6F5). Treatment of the complex salts thus obtained as intermediates with strong methylating agents affords the carbene complexes (Scheme 61).257,260... 

Bis[Ar,Ar -di(2-pyridyl)- and -di(2-pyridyl-methyl)-imidazol-2-ylidene]aurate(i) tetrafluoroborates have been prepared from the analogous silver complexes on reaction with (tht)AuCl and their structures determined. The configuration of the cations with sterically well-protected two-coordinate gold centers shows no anomalies. However, fascinating structures are found for the adducts with silver tetrafluoroborate obtained as acetonitrile... 

Flash vacuum pyrolysis of methyl imidazol-2-yl carboxylate 290 at 750°C gave 20% yield of 268 via the corresponding ketene 291. Similar pyrolysis of methyl imidazol-l-yl carboxylate 292 gave 20% of a 1 1 2 mixture of compounds 267,268, and 296. This fact can be rationalized by the pathway depicted in Scheme 71. Ketenes 291 and 295 may be intermediates formed from 293 and 294, respectively. They are products of rearrangement of 292. Similar pyrolysis of 4-imidazole carboxylic acid anilide performed at 800°C gave 267 in 20% yield (86JOC306). 

G. A. Worth, P. M. King, and W. G. Richards, Theoretical calculation of tautomer equilibria in solution. (5-)-Methyl imidazole, Biochim. Biophys. Acta 993 134 (1989). 

ICAM intercellular adhesion molecule t-MIAA tele methyl imidazole acetic acid... 

Derivatives of bzacen have been studied to a minor extent [Fe(bzacen) (N-methyl-imidazole)2]C104 [176] and [Fe(bzacen)(Him)(CN)] [185] are purely low spin, whereas [Fe(bzacen)(Him)2]BPh4 shows gradual spin crossover [185]. 

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