N-4- imidazole

N — N — — Imidazole 4,5-di-t-butylimidazole histamine dihydrochloride 2-thio-hydantoin... 

Imidazo[l, 2-n]imidazole, 1,6-dimethyl-MO calculations, 6, 979 Imidazo[ 1,2-n]imida2ole, 1,6-dimethyl-5-nitro-MO calculations, 6, 979... 

Imida2o[4,3-d]imidazole, tetrahydro-synthesis, 6, 993 Imidazo[l, 2-n]imidazoles synthesis, 6, 990, 992... 

Crystd from benzene, CCI4, CH2CI2, EtOH, pet ether, acetone/pet ether and distd deionized water. Dried at 40° under vacuum over P2O5. Distd at low pressure. Also purified by sublimation or by zone melting. [Caswell and Spiro J Am Chem Soc 108 6470 1986.] N-imidazole was crystd from benzene [Scholes et al. J Am Chem Soc 108 1660 1986]. 

The crystal structure of the C-functionalized imidazole derivative of 1,5,9-triazcyclododecane (75) shows a five-coordinate zinc with four /V-donors from ligand and chloride in a distorted trigonal bipyramidal arrangement. The Zn—N imidazole bonds are the shortest at 2.025(3) A.678 Deprotonation of the imidazole group resulted in a bridging imidazolate to form dinuclear zinc complexes. The pATa of 10.3 varies from the pATa of bound water with similar ligands (as low as 7.3) and the complex is not catalytic for the hydrolysis of esters. 

Copper, (d ) 4, square planar O-Carboxylate, N-imidazole Type II copper in oxidases... 

Cobalt, Co " (cf ) 4, tetrahedral 5 -Thiolate, thioether, N-imidazole Alkyl group transfer, oxidases... 

Ni" forms square-planar bis-complexes with the amidate anions of L-Val, L-Phe, and L-Pro. The structure of bis(Gly)-bis(imidazole)nickel(ii) has been reported and the configuration around the metal atom is cis-O(carboxyl), cis-N(amine), cis-N(imidazole). Tetra- and penta-peptide complexes of nickel(ii) consume oxygen in neutral solutions as the metal ion catalyses peptide oxidation to give a number of products, including amides of amino-acids and peptides, oxo-acids, and C02- ... 

Coordination of NO to a heme involves appreciable tc-backbonding between the Fe" and the NO such that a strong trans influence is exerted and the Fe is pulled toward the NO. This is evident in Fig. 7, where (Fig. 7a) the Fe-N(imidazole) is long compared to the usual value of 1.98 A and (Fig. 7b) where the imidazole is lost completely. Comparison of the two structures in... 

Pd(0)-catalyzed allylations of 4(5)-nitroimidazole, 2-methyl-4(5)-nitroimidazole, 4(5)-bromoimidazole and 4(5)-methoxyimidazole resulted in complicated mixtures, which did not necessarily reflect the tautomeric ratios of the starting material [7]. For example, poor regioselectivity for the products (70 and 71) was observed in the Tsuji-Trost reaction of 4(5)-bromoimidazole with cinnamyl carbonate. However, the same reaction with 4(5)-nitroimidazole and 2-methyl-4(5)-nitroimidazole led predominantly to the 1-allylation products. In addition, removal of the N-imidazole allyl groups can be selectively effected under mild conditions by Pd-catalyzed 7t-allyl chemistry [55]. 

N, possibly imidazole and S, cysteine N, imidazole or amine, and possibly H2O... 

OMe OMe OMe OMe H H = CH2OH, COOH COOMe, CH2NH2, CH2NAC, CH2-N-Imidazol... 

Amino-4,4-dimethyl-l-nitro-N -imidazole or 2-Amino-4,4-dimethyl-l-nitro-l,3-diaza-cyclo-2-pentene, H,C-N(NOj)—C. NH,... 

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