Acetyl-2-phenylimidazole

Diphenylimidazole with palladium acetate forms the cyclometallated complex 80 (X = OAc) (97AOC491). The acetate group is replaced by chloride or bromide when 80 (X = OAc) reacts with sodium chloride or lithium bromide, respectively, to give 80 (X = C1, Br). Bromide with diethyl sulfide forms the mononuclear complex 81. Similar reactions are known for 1 -acetyl-2-phenylimidazole (96JOM(522)97). 1,5-Bis(A -methylimidazol-2-yl)pen-tane with palladium(II) acetate gives the cyclometallated complex 82 (OOJOM (607)194). 

For this reason the regioselective methylation of various 4-substituted 1-acetyl-imidazoles was studied.1[2] While reaction with l-acetyl-4-phenylimidazole furnished the isomers l-methyl-5-phenylimidazole and l-methyl-4-phenylimidazole in a ratio of 93 7, reaction with l-acetyl-4-methylimidazole produced an isomer ratio of 86 14. 

Oxidation of Schiff bases of the monoamide 8 derived from diamino-maleonitrile gives 4-cyanoimidazole-5-carboxamides (Eq. 4). A new synthesis of 2-formyl-4-methyl-l-phenylimidazole 3-oxide (10) involves the fluoride-ion-promoted cyclization of the trimethylsilyl ether of JV-dichloro-acetyl-A-phenylaminopropanone oxime (9). ... 

Values of molar Kerr constants and dipole moments of nitrogen azoles and their complexes with phenols have been obtained. " These complexes are formed by an intermolecular hydrogen bond between the pyridine-type nitrogen of the azole and the phenolic proton. " The use of dipole moments in conformational studies has shown that A-aryl- and C-aryl- and A-furyl- and C-furyl imidazoles (and benzimidazoles) are nonplanar, but l-(a-furyl)-4,5-diphenylimidazoles do have a planar bicyclic fragment. The dipole moments and conformations of azolides (A-acylazoles) have been studied. In the 1-arylimidazoles the dipole is toward the aryl group. In 4,5-di-t-butylimidazole the molecule is essentially planar, but the C-4—C-5 bond is slightly stretched. Among other imidazole derivatives which have been studied by X-ray are histidine hydrochloride, 4-acetyl-amino - 2 - bromo - 5 - isopropyl -1 - methylimidazole, 4- acetyl - 5 - methyl - 2 -phenylimidazole, and imidazole-4-acetic acid hydrochloride. 

In 4,5-di-t-butylimidazole the molecule is essentially planar, but the C-4—C-5 bond is slightly stretched. Among other imidazole derivatives which have been studied by X-ray are histidine hydrochloride, 4-acetyl-amino-2-bromo-5-isopropyl-l-methylimidazole, 4-acetyl-5-methyl-2-phenylimidazole, and imidazole-4-acetic acid hydrochloride. ... 

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