Benzimidazole 2- methyl-5 -nitro

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

Amino-6-hydroxy-4-hydroxy-methyl-3-phenyl- E9a, 589 (7-OH — 4-Ar — < 1,2-oxazolo-[3,4-d]pyridazine)/Red.) Pyrido[l,2-a]benzimidazol 7-Nitro-... 

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

By using basicity data, Ridd and Smith- showed that 5-nitro- and 5-chloro-benzimidazole and their 2-methyl analogs exist essentially as mixtures of equivalent amounts of 29 and 30, and, in agreement with this ratio, 5-substituted benzimidazoles form comparable amounts of 1- and 3-derivatives on alkylation,- showing earlier alkylation ratios- to be erroneous. There are, however, other factors which can lead to the predominance of one tautomeric form. Basicity measurements indicate that 31 is preferred to the alternative non-hydro-... 

An analogous sequence leads to the anthelmintic agent, etibendazole (50). Reaction of the benzophenone 47, which can be obtained by acylation of g-nitroaniline with p-fluorobenzoyl chloride, with ethylene glycol leads to acetal 48. Sequential reduction of the nitro group and cyclization of the resulting diamine (49) with N,N-dicarbomethoxy-S-methyl thiourea gives the benzimidazole etibendazole (50) fl6]. 

Die o-Diamino-arene werden bei diesem Verfahren durch Dithionit-Reduktion von 1,3,2-Benzoselcnodi-azolen hergcstellt, was die Herstellung von 2,3-Diamino-l-nitro-benzolen gestattet. Die daraus cyclisier-baren 4-Nitro-2-methyl-benzimidazole sind nicht durch Nitrierung erhaltlich197. 

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

I l-[3,5-Bis-0-(4-methyl-benzoyl)-2-deoxy-fi- n-erythro-pentofuranosyl)-4-mtro-benzimidazol, 45% II l-[3,5-Bis-0-(4-methyl-benzoyl)-2-deoxy-f>- D-erythro-pentofuranosyi]-7-nitro-benzimidazol 30% Schmp. 124-125°... 

In much the same vein, nitration of 2,3-dimethylpyridine Al-oxide (49-1) affords the nitro derivative (49-2). The newly introduced nitro group is then displaced by the aUcoxide from 3-methoxypropanol to afford the corresponding ether (49-3). Proceeding much as above, the methyl group at the position adj acent to the nitrogen is converted to its chloride (49-5). Condensation with benzimidazol-2-thiol then affords rabeprazole (49-6) [52]. 

A reaction of 4-nitro-l,2-phenylendiamine with benzotrichloride in the presence of sodium methylate [367] has been described. In this case 2-phenyl-5(6)-nitroben-zimidazole is obtained without preliminary extraction of the ortho-ester of benzoic acid. Sometimes acylated polynitroanilines, with one of the groups in the orthoposition to the amino group, are used as the initial products. On partial reduction of such compounds the cyclization to benzimidazoles takes place [85, 368], For example, the reduction of 2,4-dinitroacetanilyde with ammonium sulfide has afforded 2-methyl-5(6)-nitrobenzimidazole (Scheme 2.41) [85],... 

Preparation of R-(+)-3-A-trifluoroacetyl-6-bromo-2,3-dihydro-7-methyl-5-nitro-lH-pyrrolo-[l,2-a]benzimidazole... 

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... 

Pyrido[l,2-a]benzimidazol 4-Methyl-1 -nitro-2-oxo-2,10-dihydro-E15/3, 2790 [cycl. 

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

---