Benzimidazole, l-methyl-2-

Benzimidazole, l-methyl-2-trichloromethyl-substitution reactions, 5, 432 Benzimidazole, naphthoyl-, 1, 327 Benzimidazole, 5-nitro-alkylation, 5, 390 Benzimidazole, 6-nitro-1-oxide... 

Benzimidazoles, 2,3-dihydro-, by Nu addition at C-2, 56, 203 Benzimidazole, 2-fluoro-, 59, 272 Benzimidazole, 1-methyl-, ring expansion to chloroquinoxalines, 59, 305 Benzimidazole, l-methyl-2-(5 -methyl-2 -thienyl)-, bromination, 57, 319 Benzimidazole 3-oxides, chloro-deoxygenation, 59, 270 Benzimidazoles, 2-perfluoroalkyl-, 60, 25 Benzimidazoles, 2-(l-pyridinio)-, 60, 204 Benzimidazoles, 2-(2-pyridinioethyl)-, elimination reactions, 60, 246 Benzimidazoles, tetrafluoro-, 59, 14 Benzimidazole-2-carboxylic ester 3-oxide, 7-nitro-5-trifluoromethyl-, 60, 17 Benzimidazolium salts, l-amino-3-alkyl-, reaction with activated acetylenes, 56, 138... 

H CHS c6h5 1h Riickfl. 1 -Amino-benzimidazol l-Amino-2-methyl-... l-Amino-2-phenyl-... 70 69 59 156-156,5 164-165 204-205 ... 

Analog erhalt man 2-MethyI-(l-methyl-2-nitro-ethyI)-benzimidazol [82% Schmp. 118-119° (Benzol/Pe-trolether)]. 

Methyl-benzimidazol dimerisiert ebenfalls bei der Acylierung mit Benzoylchlorid und Tri-ethylamin als Base zu 3-Benzoyl-l-methyl-2-(l-methyl-2-benzimidazolyl)-2,3-dihydro-benzimid-azol (I 37% Schmp. 170-171°). Fuhrt man die Umsetzung statt bei 20° bei 140° (Ampulle) durch, so isoliert man 2-Benzoyl-1-methyl-benzimidazol (II 92% Schmp. 71 - 72°)417. Das Di-mere I laBt sich thermisch ebenfalls zu 2-Benzoyl-l-methyl-benzimidazol ( 61%) spalten. Die basische Oxidation des Dimeren I liefert dagegen fast quantitativ 1, Y-Dimethyl-2,2-bi-(benzimidazolyl) (III)417. 

Die Nitrosierung von 2-Amino-1-methyl-benzimidazol fiihrt zu l-Methyl-2-nitroswnino-benz-imidazol, das thermisch in Benzol Stickstoff abspaltet und aryliert wird638. 

Erhitzt man l-Methyl-2-phenyl-benzimidazol mit Natriumamid, so erhalt man unter Addition/C,C-Spal-tung und Eliminierung 2-Amino-l-methyl-benzimidazol (55%)433 ... 

In the reaction of a mixture of E- and Z-isomers of l-methyl-2-acetyl-benzimidazole oxime (31) in the KOH/DMSO system (90-95°C, atmospheric acetylene pressure, mass oxime 31/KOH/DMSO ratio 1 1 20, 3 hr), the pyrrole ring is formed only from the Z-isomer. Recovered oxime... 

The yield of l-methyl-2-(2-pyrrolyl)benzimidazole (32) is 58% based on the consumed Z-isomer (Table XVII). Its H-NMR spectrum (DMSO-D6, ppm) shows 3.96 (s, NMe), 6.28 (m, 3H), 6.83 (m, H4), 7.03 (m, H5), 7.23, and 7.56 (benzene protons). The less coplanarZ-oximate anion is likely to encounter less sterical hindrance upon acetylene molecule attack. 

Alan F. Williams, Claude Piguet, and Gerald Bemardelli [C02L3] + (L = bis[l-methyl-2-(6 -methyl-2 -pyridyl)benzimidazol-5-yl]methane), similar to helical DNA and RNA structure... 

Benzimidazol 1 -Methyl-2-nitrosami-no-E8c, 371 (NH2 - NH-N02) Phthalazine 5,7-Diamino-l, 4-dihydroxy- E9a, 752 [3,5-(NH2)2 —phthalanhydrid/N2H4] Pyrazin 5-Amino-6-cyan-3-metho-xycarbonyl-2-methyl- E9b/2,... 

Benzimidazol l-Cyan-2-methyl-E19b, 1399 (Carben-1,3-dipolare Cycloaddition)... 

Benzimidazol 3-(Carboxy-methyl)-l-methyl-2-nitrosimino-2,3-dihydro- E14b, 758 (N-Nitrosier.)... 

Amin Ethyl-(3-indolyl-methyl)-nitro-E16a, 1168 (N-Alkylier.) Benzimidazol 2-Methyl-(l-methyl-2-nitro-ethyl)- E8c, 337 (NH - N — R)... 

Benzimidazol l- (Bis-[2-hydroxy-ethyl]-amino)-methyl -6-nitro-E8c, 345 (NH - N —CH2-NR2)... 

It is a general rule that imidazoles and benzimidazoles are resistant to Friedel-Crafts reactions. This is not surprising since such basic compounds must be markedly deactivated in the presence of Lewis acids. Imidazolin-2-ones appear to be an exception and apparently possess sufficient activation to react. Reactions between imidazoles and Af-methylfor-manilide and phosphoryl chloride are also unproductive. With 4,5-diphenylimidazole, phenyl isocyanate at 80 °C gives products of both N- and C-substitution, but in boiling nitrobenzene only the latter (86) is formed. 2-Methyl-4-phenylimidazole gives (87) under the same conditions, and 1,3-diphenylimidazolium perchlorate is transformed by potassium t-butoxide into a ylide which reacts at C-2 with phenyl isothiocyanate. Sufficient activation is present in l-methyl-2-phenyl-4-phenylaminoimidazole for it to react by substitution at C-5 with acetic anhydride (71JOC3368). 

The kinetics and mechanism of the transalkylation reaction between 2-alkoxy-1-methyl-benzimidazoles and thiophenol have been studied. The results demonstrate a rapid protonation of the azole followed by an 5n2 reaction which forms the benzimidazolinone. The basicity of the benzimidazole and the pH both affect the reaction rate (Scheme 126). The corresponding sulfur analogue, l-methyl-2-methylthiobenzimidazole, does not react with thiophenol, probably because of the poor electron-donating ability of the sulfur atom of thiophenate (71 JCS(B)2299). 

Abe et al. reported that the imidazol [l,2-a]pyridine moiety of the basic framework of a class of the non-peptide bradykinin B2 receptor antagonists (11, Figure 15.14) could be successfully replaced by several heterocyclic bioisosteres. Among those, the l-methyl-2-methoxy-l//-benzimidazole, 2-methylquinoxaline and 2-methylquinoline derivatives showed potent B2 binding affinities against both human and guinea pig B2 receptors (Figure 15.14). 

With a view to the relationship between the structure and action of glyodin, the research in the benzimidazole series was first centred on active substances containing long alkyl chains. Of these, l-methyl-2-phenyl-3-dodecylbenzimidazolium ion has been used in plant protection in the form of its insoluble salts. These salts such as the... 

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