Imidazole 2-phenyl-1,4,5-trimethyl

Imidazole, 4-formyl-5-hydroxy-l-phenyl-mesoionic, 5, 372 Imidazole, 2-formyl-1-methyl-mass spectra, S, 360 Imidazole, 2-formyl-l,4,5-trimethyl-... 

The reaction of nitrone 99 with dimethyl acetylenedicarboxylate (DMAD) at room temperature in CH2CI2 gave a colorless crystalline product that has been identified as trimethyl 3,3-dimethyl-l-phenyl-377-pyrrolo[l,2-f]imidazole-5,6,7-tricarboxylate 100. A mechanism explaining this transformation has been reported (Equation 13) <2001RCB882>. 

Diamino-2-phenyl imidazolium-chlorid kann auch durch Umsetzung von 2-Phenyl-imidazol mit 0-(2,4,6-Trimethyl-benzolsulfonyl)-hydroxylamin und Natriumhydrogencarbonat als N-Aminicrungs-Reagens in Tetrahydrofuran und anschlieBenden Anionen-Austausch hergestellt werden678. 

Initially, a solution of cinnamaldehyde and 4-chlorobenzaldehyde in tetrahydrofuran (THF) was treated with different azolium salts under basic conditions (Scheme 6). The use of thiazolium salt 4 resulted in no formation of the desired y-butyrolactone, only benzoin products were formed. In contrast, using the NHC IMes [l,3-di(2,4,6-trimethyl-phenyl)imidazol-2-ylidene generated in situ from the salt IMesHCl by deprotonation], y-butyrolactone 3a was isolated in 53% yield and a 80 20 cisltrans ratio. This different outcome might be explained by the increased steric demand of IMes compared to 4 (Scheme 7). Most likely, IMes reversibly adds to the aldehyde groups of both substrates resulting in the intermediates la and 2a. Whereas the mesityl groups shield the former aldehyde carbon in both intermediates, the conjugate position of 2a is still accessible and can add to the electrophilic aldehyde. 

Alkaline cleavage of 2,4,4-trimethyl-5-phenyl-4//-imidazole 1-oxide gives oximes of a-acylaminoketones as products (80AHC(27)24l). 

The mass spectrum of I-methyl-4-nitroimidazole-5-carboxylic acid amide shows the elimination of water by an electron impact as distinct from the usual thermal process. In l,4,5-trimethylimidazole-2-carboxylic acid the principal loss is that of CO2. Subsequent loss of O, OH, and HCN was also observed (Schofield et al., p. 173). Ferguson and Schofield (pp. 172,173) have reported considerable data for imidazole JV-oxides. Thus 1-methoxy-4,5-dimethyl-2-phenylimidazole (which loses OCH3 and CH3CN from the fragment m/e 171) is readily distinguished from l,4,5-trimethyl-2-phenyl-imidazole 3-oxide (loss of O and OH). The spectra of 1-benzylimidazoles are dominated by the tropylium ion. ... 

The thermal rearrangement of 2,4,4-trimethyl-5-phenyl-4if-imidazole 1-oxide to 2,4,4-trimethyl-l-phenyl-2-imidazolin-5-one appears to involve a phenyl migration, while alkaline cleavage gives oximes of a-acyla-minoketones." ... 

Other applications of the technique include examination of the nickel(II) complex with imidazole. <86JA6470>, and mechanistic studies of the dehydrogenation of 1,2,3-trimethyl-2-phenyl-benzimidazoline <84CHE817,87CHE525). 

Tikkanen, L. M., Sauri, T. M., and Latva-kala, K. J., Screening of heat-processed Fitmish foods for the mutagens 2-amino-3,8-dimethyl imidazole [4,5f] quinoxahne, 2-amino-3,4,8-trimethyl imidazole [4,5f] quinoxahne and 2-amino-l-methyl-6-phenyl imidazo [4,5b] pyridine. Food Chem. Toxicol, 31, 717-721, 1993. 

Acyl imidazoUdes. These compounds resemble acyl chlorides in reactivity and are thus useful in synthesis. Masamune has observed that they can be prepared by reaction of phenyl and 2,2,2-trifluoroethyl esters with N-(trimethyl-silyl)imidazole at 20° in the presence of a trace of sodium phenoxide (1). Alkyl... 

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