Imidazole 1- alkyl-5-nitro

By way of illustration, nitration of 2-isopropyl-imidazole (55) affords the 4- or 5-nitro derivative (56, 57). Alkylation with methyl iodide affords isomer 58. The same reaction carried out with dimethyl sulfate under neutral or acidic conditions provides the isomer methylated at the alternate... 

In a similar vein, alkylation of 4-(5)-nitro-imidazole with N-(2-chloroethyl)morpholine affords a mixture of N-alkylated imidazoles (61 and 62). The compound containing the adjacent ring substituents (61) is the antitrichomonal agent nimorazole.15... 

A still different scheme is used for the preparation of the benzimidazole buterizine (74). Alkylation of benzhydrylpiperazine with substituted benzyl chloride 70 gives the intermediate 7U Nucleophilic aromatic displacement on this compound by means of ethyl amine leads to reduction of the nitro group then gives the diamine T. Treatment of that with the orthoformate ester of pentanoic acid serves to form the imidazole ring. There is thus obtained the peripheral vasodilating agent buteri zi ne (74). ... 

Imidazol und einfache Alkyl-imidazole besitzen im UV-Spektrum im Bereich > 200 nm nur Banden mit geringer Extinktion. Durch Aryl-Substituenten oder funktionclle Gruppen (z.B. Formyl, Nitro) steigt die Absorbtion betrachtlich68 ... 

Neben den bereits in Band VI genannten Beispielen konnen auch 1-Alkyl-5-nitro-imidazole in 2-Stellung hydroxymethyliert werden (1 -Alkyl-2-hydroxymethyl-5-nitro-imidazole). Diese Umsetzung wird normalerweise in Dimethylsulfoxid mit Paraformaldehyd bei 120-130" durchgefuhrt746- 748. 

Benhida, R. Gharbaoui, T. Lechevallier, A. Beugelmans, R. Derives N-alkyles du 4-nitro-imidazole. Synthese par chimie radicalaire (SrnI) et amenagements fonctionnels. Bull. Soe. Chim. Fr. 1994, 333, 200-209. 

Syntheses of fused mesoionic heterocycles such as [l,2,3]triazolo[l,5-a]-quinoline, -quinazoline, -quinoxaline, and -benzotriazine derivatives have been described <02T3185>. Cyclizations of alkyl 2-benzoylamino-(4,5-dicyano-1 //-1,2,3-triazol-1 -yl)propenoates gave [1,2,3]triazolo[l, 5-a]pyrazines <02H(56)353>. Reaction of triethyl N-( 1 -ethy 1-2-methy 1-4-nitro-l//-imidazol-5-yl)phosphorimidate with aryl isocyanates provided a route to 2-aryI-2//,4//-imidazo[4,5-fif][l,2,3]triazoles <02JCS(P 1)1968>. 2-(A,A-Diphenylamino)-4-hydrazino-6-... 

It is noted [321] that alkylated 5-nitroimidazoles show more distinct maxima in a field of 220-260 nm than the corresponding 4-nitroisomers. This band is also slightly displaced to the long-wave area (7-13 nm) for 5-nitrosubstituted compounds in comparison with 4-nitroimidazoles. Thus, statistical analysis of the absorption spectra of 1-alkylnitroimidazoles allows establishing the nitro group position in the ring that is extremely valuable in the nitration chemistry of imidazoles. The absorption bands of... 

In a patent138 a nitro-substituted cyclic enediamine was acylated by l-methyl-3-(phenoxycarbonyl)imidazolium chloride, prepared from the reaction of phenoxycarbonyl chloride and imidazole, to give product 168. Hydrolysis of 168 leads to the / -carbon atom acylated product 169. Unlike the alkylation which occurs only at the /7-carbon atom, acylation takes place both at the / -carbon and at the secondary nitrogen atom giving 168 (equation 63). 

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