Synthesis of Some New Imidazo[4,5-B]Pyridine Derivatives Using 2-Cyanomethyl-1-Methyl-1H-Imidazo[4,5-B]Pyridine

Abstract

The reactions of 2-cyanomethyl-1-methyl-1H-imidazo[4,5-b]pyridine with isothiocyanates, nitroso compounds, acid chlorides, and thioglycolic acid were investigated. New imidazo[4,5-b]pyridine derivatives with various substituents in 2-position and derivatives of the new pyrrolo[2′,1′:2,3]imidazo[4,5-b]pyridine ring system were synthesized. The compounds obtained were tested in vitro for their tuberculostatic activity.     

Synthesis of imidazo[4,5-b]pyridines from aminoimidazolecarbaldehydes

4-Amino-1,2-dimethylimidazole-5-carbaldehyde (1) and 5-amino-1-methylimidazole-4-carbaldehydes 3 were prepared by reduction of the corresponding aminoimidazolecarbonitriles 2 and 4. Condensation of 1 and 3 with carbonitriles, ketones and polyfunctional carbonyl compounds bearing the-CH₂CO-moiety afforded to the imidazo[4,5-b]pyridine derivatives.     

Reduction of Imidazo[4,5-c]pyridine and [1,2,3]Triazolo[4,5-c]pyridine Derivatives to Spinaceamines and 2-Azaspinaceamines

Reduction of 1-substituted [1,2,3]triazolo[4,5-c]pyridines with nickel-aluminum alloy in aqueous alkali gave 2-azaspinaceamines. Reduction of imidazo[4,5-c]pyridine and [1,2,3]triazolo[4,5-c]pyridine derivatives with formic acid in the presence of triethylamine resulted in formation of 5-formylspinaceamines and 2-azaspinaceamines. The 5-formyl group in the latter can be removed by acid hydrolysis. Unsubstituted 2-azaspinaceamine, an aza analog of natural spinaceamine, was synthesized for the first time.     

Imidazo [4,5-c] - and [4,5-6] pyridines

The synthesis of novel imidazo[4,5-c]pyridines 11-13 and imidazo[4,5-b]pyridines 18-20 is described using 2 as the starting material. The synthesis is generally applicable for the introduction of a wide variety of substituents.     

Reactions of 1-Substituted Benzo[4,5]imidazo[1,2-a]pyridines

Bromination of 1-oxo(imino, amino)benzo[4,5]imidazo[1,2-a]pyridines gave the corresponding 2-bromo derivatives. Acylation using the Vilsmeier complex in acetic anhydride gave the N-formyl and N-acetyl derivatives. The reaction of the amine with the Vilsmeier complex, acetyl acetone, ethyl acetoacetate, and 2,5-dimethoxytetrahydrofuran occurs at the amino group.     

A novel preparation of thiazolo[5,4-c]pyridines and the synthesis of some imidazo[4,5-c]pyridines and oxazolo[4,5-c]pyridines

Diethoxymethyl acetate was used to cyclize o-disubstituted aminopyridines to oxazolo[4,5-c]pyridines and imidazo[4,5-c]pyridines. All the possible imidazole-methylated imidazo[4,5-c]pyridines were prepared. A novel synthesis of 2-substituted thiazolo[5,4-c]pyridines and 4-amino-3-pyridinethiol was discovered.     

N-oxides of imidazo[4,5-b]quinoxalines and imidazo[4,5-b]pyrazines

The N-oxides and N,N-dioxides of methyl derivatives of imidazo[4,5-b]quinoxaline and imidazo[4,5-b]pyrazine were synthesized. The higher reactivity of the 2-methyl group in the N-oxides of 2-methylimidazo[4,5-b]quinoxaline as compared with the corresponding unoxidized derivatives was demonstrated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1266–1270, September, 1972.     

Palladium(0)-catalyzed phenylation of imidazo[4,5-b]pyridines

The tetrakis(triphenylphosphine)palladium(O)-catalyzed coupling of benzeneboronic acid with 2-chloro, 6-bromo and 6-bromo-2-chloro derivatives of 1- and 3-methylimidazo[4,5-b]pyridines to novel 2-phenyl-, 6-phenyl- and 2,6-diphenylimidazo[4,5-b]pyridines is described. The phenylation of imidazo[4,5-b]-pyridines containing labile hydrogens was not successful.     

Quaternization of 1H-imidazo[4,5-b]pyridine and 4-methyl-4H-imidazo[4,5-b]pyridine

Unsubstituted imidazo[4,5-b]pyridine adds methyl iodide to the pyridine N atom. Treatment of the resulting iodide with base forms 4-methyl-4H-imidazo[4,5-b]pyridine. This nucleophile can readily add methyl iodide to form only one salt, 1,4-dimethylimidazo[4,5-b]pyridinium iodide.L. M. Litvinenko Institute of Physical Organic Chemistry and Coal Chemistry, Ukraine Academy of Sciences, Donetsk 340114. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1232–1233, September, 1994. Original article submitted june 17, 1994.     

Synthesis and antituberculotic activity of some new imidazo[4,5-b]pyridine derivatives

The reactions of 2-acetylimidazo[4,5-b]pyridine hydrazone with some alkyl-and arylisothiocyanates and some orthoesters were carried out. Various new derivatives of the titled compound such as thiosemicarbazones, ethoxymethylenehydrazones, and derivatives of the new pyrido-[3′,2′:4,5]imidazo[1,2-d][1,2,4]triazine ring system were obtained. Biological data for selected compounds are presented. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1571–1579, October, 2006.     

Studies on the chemical synthesis of potential antimetabolites. 30. Regioselective introduction of a chlorine atom into the imidazo[4,5-b]pyridine nucleus

Reactions of some imidazo[4,5-b]pyridine 4-oxides with phosphoryl chloride are described. Treatment of N-1-substituted imidazo[4,5-b]pyridine 4-oxides with phosphoryl chloride led to the predominant formation of 7-chloro derivatives. This feature was successfully applied to the preparation of a chloroimidazo[4,5-b]pyridine nucleoside, which served as an important precursor of 1-deazaadenosine.     

Synthesis of New Imidazo[4,5-b]pyridine Derivatives

New imidazo[4,5-b]pyridine derivatives with various substituents in the 2-position (,-unsaturated ketones, imines, ²-pyrazolines, pyrimidines, 1,2,3,4-tetrahydropyrimidines) and derivatives of the new pyrido[3',2':4,5]imidazo[1,2-d][1,2,4]triazine ring system were synthesized. Biological data for selected compounds are presented.     

Structure and properties of 1- and 3-hydroxytriazolo [4,5-b] pyridines

It is shown that 1-hydroxytriazolo[4,5-b]pyridine exists in alcohol solution primarily in the N-oxide form, whereas 3-hydroxytriazolo[4,5-b]pyridine exists in the hydroxy form. 4-Methyl-triazolo[4,5-b]pyridine 1-oxide is formed in the methylation of 1-hydroxytriazolo[4,5-b]pyridine, whereas 3-methoxytriazolo[4,5-b]pyridine is formed in the methylation of 3-hydroxytriazolo[4,-5-b]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1418–1421, October, 1976.     

Synthesis of Substituted Imidazo[4,5-b]pyridines as Analogues of the DNA Binding Fluorochrome Hoechst 33258

Various substituted imidazo[4,5-b]pyridine analogues of Hoechst 33258 have been synthesized to explore the potential of selective helicase blockade and anticancer activity. The target compounds II a, b & d were obtained by condensation of the appropriate functionalized diamine and substituted benzimidazole aldehydes in nitrobenzene.     

咪唑并吡啶类化合物的合成及其应用*

咪唑并吡啶类化合物具有与吲哚、氮杂吲哚等类似的特殊结构和良好的生物活性,在医药和农药工业有着广泛的应用,成为有机化学家和药物化学家的研究热点。咪唑并吡啶类化合物主要有咪唑并[4,5-b]吡啶、咪唑并[4,5-c]吡啶、咪唑并[1,2-a]吡啶和咪唑并[1,5-a]吡啶等4个类型。本文阐述了近年来咪唑并吡啶类化合物的合成研究进展和应用情况,主要介绍了咪唑并[4,5-b]吡啶和咪唑并[4,5-c]吡啶这两类化合物的合成方法和在医药及农药领域的应用。     

Synthesis and anticonvulsant activity of 1-benzyl-4-alkylamino-1H-imidazo[4,5-c]pyridines

Four 3-deaza analogues of the potent anticonvulsant purine, BW A78U, were synthesized and tested for anticonvulsant activity. The imidazo[4,5-c]pyridines 9–12 were prepared in two steps from 4-chloro-1H-imidazo[4,5-c]pyridine ( 2 ). The compounds were potent anticonvulsant agents against maximal electroshock-induced seizures in rats with i.p. ED₅₀ ranging from 2 to 3.5 mg/kg. However, these 3-deazapurines were appreciably more toxic than BW A78U, which precluded their development as potential antiepileptic agents.     

Synthesis of imidazo[4,5-a]acridones and imidazo[4,5-a]acridines as potential antibacterial agents

Abstract  

New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl₃. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug.     

Synthesis and transformation of N-oxides of some imidazo[4,5-b]pyrazine derivatives

The Böckelheide reaction was accomplished with a number of imidazo[4,5-b]pyrazine N-oxides, and the N-oxidation of the resulting acetoxy(hydroxy)methyl derivatives of imidazo[4,5-b]pyrazine and 6-bromo-1-methylimidazo[4,5-b]pyrazine was studied. The hydrolytic cleavage of 6-bromo-1-methylimidazo[4,5-b]pyrazine and its 4-N-oxide was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 690–693, May, 1975.     

Preparation of new nitrogen-bridged heterocycles 72. A new approach to 1-acyl-3-(substituted methylthio)thieno[3',4':4,5]imidazo[1,2-a]pyridine derivatives. [corrected

The alkaline treatment of the pyridinium salts, readily available from the S-alkylations of 3-amino-4-(1-pyridinio)thiophene-5-thiolates with various alkyl halides, in chloroform at room temperature afforded the corresponding thieno[3',4':4,5]imidazo[1,2-a]pyridine derivatives in low to moderate yields via the intramolecular cyclization of the resulting 1,5-dipoles followed by the aromatization of the primary cycloadducts. Interestingly, the reactions using unsymmetrical 3-amino-4-[1-(3-methylpyridinio)]thiophene-5-thiolates afforded only 8-methylthieno[3',4':4,5]imidazo[1,2-a]pyridines and the other 6-methyl derivatives were not formed at all. In addition the isolation of a byproduct in the condensation reaction of pyridinium salt with the solvent (CHCl?) is also discussed.     

Preparation of 2-aryl and 2-aryloxymethyl imidazo[1,2-a]pyridines and related compounds

A series of substituted 2-aryl imidazo[1,2-a]pyridines has been prepared in which a variety of substituents are introduced on the 4′-position of the phenyl ring and on the 3, 5 , 6 or 7 position of the heterocyclic ring. Most examples have acetamido, bromo, cyano, or formyl substituents at the 4′-position. Analogous imidazo-[2,1-b]fhiazoles and imidazo[1,2-a]pyrimidines have also been prepared. Another series of compounds consisting of 4′-formylphenoxymethyl derivatives of imidazole, the three positional isomers of pyridine, thiazole, benzimidazole and ring-substituted imidazo[1,2-a]pyridines has been prepared. 2-(4′-Formylphenylethenyl) derivatives of imidazole and imidazo[1,2-a]pyridine were also prepared.