Synthesis of 4,7-dihydro-4-oxopyrrolo[2,3-b]pyridine-5-carboxylic acid derivatives as potential antimicrobial agents

Synthetic approaches to 1-benzyl-7-alkyl-2,3-dimethyl-4,7-dihydro-4-oxopyrrolo[2,3-b]pyridine-5-carboxylic acids from 1-benzyl-2-amino-3-t-butoxycarbonyl-4,5-dimethylpyrrole are reported.     

Synthesis of 3-benzoyl-4,7-dihydro-7-oxopyrrolo[3,2-b]pyridine-6-carboxylic acid derivatives as potential antimicrobial agents

A series of twelve newly synthesized derivations of 3-benzoyl-4,7-dihydro-7-oxopyrrolo[3,2-b]pyridine-6-carboxylic acid from 2-methyl-3-benzoyl-4-aminopyrrole is reported.     

Synthesis of 4,7-dihydro-4-oxoisoxazolo[5,4-b]pyridine-5-carboxylic acid derivatives as potential antimicrobial agents

Synthetic approaches to 3-substituted-7-ethyl-4,7-dihydro-4-oxoisoxazolo[5,4-b]pyridine-5-carboxylic acid derivatives from 3-substituted-5-aminoisoxazoles are reported.     

Synthesis of 7-oxopyrrolo[3,2-B]pyridine-6-carboxylic acid derivatives as potential antimicrobial agents

A route for the synthesis of various derivatives of 7-oxopyrrolo[3,2-b]pyridine-6-carboxylic acid from 2-methyl-3-carbomethoxy-4-aminopyrrole is reported.     

Synthesis of 1,4-dihydro-4-oxopyrrolo[1,2-b]pyridazine-3-carboxylic acids and 1,4-dihydro-4-oxoimidazo[1,5-b]pyridazine-3-carboxylic acids as potential antibacterial agents

To check the antibacterial potential of two families of aza analogues of the quinolones, 1,4-dihydro-4-oxopyrrolo[1,2-b]pyridazine-3-carboxylic acids and 1,4-dihydro-4-oxoimidazo[1,5-b]pyridazine-3-carboxylic acids, we have prepared a few derivatives in theses families using N-aminopyrrole and N-aminoimidazole derivatives as starting building blocks and the classical pathways of the quinolone series. The compounds showed no interesting antibacterial activity.     

Synthesis of 8-cyano-1,4-dihydro-4-oxopyrrolo[1,2-a]pyrimidine-3-carboxylic acids as potential antimicrobial agents

The preparation of a variety of 8-cyano-1,4-dihydro-7-phenyl-4-oxopyrrolo[1,2-a]pyrimidine-3-carboxylicacids and 8-cyano-1,4-dihydro-7-p-fluorophenyl-4-oxopyrrolo[1,2-a]pyrimidine-3-carboxylic acids is described.     

Synthesis of certain pyrrolo[2,3-b]pyridine-5-carboxylic acid derivatives as potential antimicrobial agents

Summary A synthetic approach to new 1-benzyl-7-alkyl-2,3-dimethyl-4-oxopyrrolo[2,3-b]pyridine-5-carboxylic acids using 5,6-dimethyl-2,4-dioxopyrrolo[2,3-d][1,3]oxazine as the starting material is reported. The antimicrobial activity of these compound is reported.

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Synthese von Pyrrolo[2,3-b]pyridin-5-carbonsäure-Derivaten als potentielle antimikrobielle Substanzen

Zusammenfassung Die Synthese von neuen 1-Benzyl-7-alkyl-2,3-dimethyl-4-oxopyrrolo[2,3-b]pyridin-5-carbonsäuren durch Verwendung von 5,6-Dimethyl-2,4-dioxopyrrolo[2,3-d][1,3]oxazinen als Ausgangsmaterial wird beschrieben. Die antimikrobielle Aktivität dieser Substanzen wurde geprüft.

     

Synthesis of 1,4-dihydro-4-oxopyridazino[1,6-a]indole-3-carboxylic acids and 1,4-dihydro-4-oxopyrido[3′,2′:4,5]pyrrolo[1,2-b]-pyridazine-3-carboxylic acids as potential antibacterial agents

A few aza analogues of the quinolones have been prepared in the two families of the 1,4-dihydro-4-oxopyridazino[1,6-a]indole-3-carboxylic acids and the 1,4-dihydro-4-oxopyrido[3′,2′:4,5]pyrrolo[1,2-b]-pyridazine-3-carboxylic acids to check their antibacterial potential. One compound 6c shows antibacterial activities of the level of nalidixic acid and represents a new lead structure differing from the classical quinolones.     

Synthesis and antibacterial activity of 7-ethyl-3-methyl-4,7-dihydro-4-oxoisothiazolo[5,4-b]pyridine-5-carboxylic acid

The synthesis of the quinolone, 7-ethyl-3-methyl-4,7-dihydro-4-oxoisothiazolo[5,4-b]pyridine-5-carboxylic acid 4 was accomplished utilizing the Gould-Jacobs dependent route. The compound had very weak in vitro activity as compared to nalidixic acid versus E. coli, P. aeruginosa, K. pnuemoniae, S. aureus and P. mirabilis.     

Synthesis of 5-methylfuro[3,2-b]pyridine-2-carboxylic acid

Oxidation of 3-hydroxy-6-methyl-2-hydroxymethylpyridine with manganese dioxide yielded the corresponding aldehyde, the condensation of which with diethyl bromomalonate furnished hydroxydihydrofuro[3,2-b]pyridinediearboxylie acid ester. Saponification of the diester with concentrated hydrochloric acid afforded the hydrochloride of 5-methylfuro[3,2-b]pyrjdine car-boxylic acid.     

Synthesis of [1]benzopyrano[3,4-b] [1,4]oxazines as potential antidepressants

Stereospecific syntheses, from Δ-3-chromene, of cis and trans-4-aminochroman-3-ols, 5 and 8 , and their conversion into cis and trans-1,2,3,4a,5,10b-hexahydro[1]benzopyrano[3,4-b][1,4]-oxazines, 15 and 16 , are described.     

Synthesis of 7-ethyl-4,7-dihydro-4-oxo-2-(4-pyridinyl)thieno[2,3-b]pyridine-5-carboxylic acid

7-Ethyl-4,7-dihydro-4-oxo-2-(4-pyridinyl)thieno[2,3-b]pyridine-5-carboxylic acid ( 4 ), an analog of nalidixic acid, was synthesized in seven steps starting from commercially available 4-methylpyridine. Bacterial susceptibility to compound 4 was tested and the title compound was found to exhibit only weak antibacterial activity against a variety of pathogens including S. Aureus, E. Coli and P. Aeruginosa.     

A convenient synthesis of 3,4-dihydro-2-methyl-3-oxo-2H-1,4-benzoxazine-2-carboxylic acids and 3,4-dihydro-2-methyl-3-oxo-2H-pyrido[3,2-b]-1, 4-oxazine-2-carboxylic acid

A convenient one pot synthesis of ethyl 3,4-dihydro-2-methyl-3-oxo-2H-1,4-benzoxazine-2-carboxylates and 3,4-dihydro-2-methyl-3-oxo-2H-pyrido[3,2-b]-1,4-oxazine-2-carboxylates and their conversion into the respective carboxylic acids are described.     

Synthesis of 4H-furo[3,2-b]indole derivatives. III. Preparation of 4H-furo[3,2-b]indole-2-carboxylic acid derivatives

Methyl or ethyl 4H-furo[3,2-b]indole-2-carboxylates (Va,b) were prepared from deoxygenation of methyl or ethyl 5-(2-nitrophenyl)-2-furoates (IIIa,b) and thermolysis of methyl or ethyl 5-(2-azidophenyl)-2-furoates (VIIIa,b). 4H-Furo[3,2-b]indole-2-carboxylic acid amides (XIa-h) were obtained by the reaction of 4H-furo[3,2-b]indole-2-carboxyl chloride (X) with the appropriate amines.     

Synthesis of pyrazolo[3,4-b][1,4]diazepines and pyrazolo[3,4-b]pyrazines

The synthesis and structure elucidation of new pyrazolo[3,4-b][1,4]diazepines and pyrazolo[3,4-b]pyrazines are reported and the characterisation of isomers and tautomers by proton and carbon-13 nmr are discussed. In some case only NOE experiments allow us to identify the isomeric structure.     

Discovery of 4H-thieno[3,2-b]pyrrole derivatives as potential anticancer agents

In this study, we describe the discovery of the 4H-thieno[3,2-b]pyrrole derivatives as an useful scaffold to obtain potent lead compounds for the treatment of colon cancer. We first started with the 4H-thieno[3,2-b]pyrrole derivatives which come from compound libraries screening, and then optimized their structures based on the cellular activities and pharmacophore models. The inhibition rate of cell growth assay demonstrated that this series compounds showed better inhibitory activities against colon cancer cells than other tested tumor cells. Moreover, the target of the most active compound 8i was explored by target fishing strategy and validated by molecular docking and biological activity analysis. The results of apoptosis and flow cytometry demonstrated that compound 8i induces cell apoptosis probably by inhibiting activity of methionine aminopeptidase 2, therefore compound 8i may be a potent inhibitor to methionine aminopeptidase 2.     

Rearrangement of 2-aminofuro[3,2-b]pyridine-3-carboxylic esters

Ethyl 2-aminofuro[3,2-b]pyridine-3-carboxylate rearranges with sodium ethoxide in ethanol to 2-oxo-3-cyano-2,3-dihydro[3,2-b]furopyridine; the corresponding p-nitrophenyl ester undergoes the same rearrangement by dilute aqueous sodium hydroxide. In the first case it was possible to isolate the labile intermediate, which was shown to be the hemiacetal of the above mentioned cyanolactone.     

A convenient synthesis of 1,4-dihydro-4-oxopyridazino[3,4-b]quinoxalines by a ring transformation of 1,2-diazepino[3,4-b]quinoxalines

The reaction of the 1,2-diazepino[3,4-b]quinoxalines 2a,b or 3a,b with N-bromosuccinimide/water resulted in ring transformation to give the 1,4-dihydro-4-oxopyridazino[3,4-b]quinoxalines 4a,b , respectively.     

Synthesis and keto-enol tautomerism of ethyl 4-oxo-3,4-dihydro-1H-pyrano[3,4-b]quinoline-3-carboxylate

An efficient method has been developed for the synthesis of a novel β-keto ester-containing pyranoquinoline compound, i.e., ethyl 4-oxo-3,4-dihydro-1H-pyrano[3,4-b]quinoline-3-carboxylate. The method entails a two-step synthesis. The first step involves the Williamson-type reaction of ethyl 2-bromomethyl-3-quinoline-3-carboxylate with ethyl hydroxyacetate in anhydrous benzene to afford the intermediate ethyl 2-[(2-ethoxy-2-oxoethoxy)methyl]quinoline-3-carboxylate. The second step includes the Dieckmann condensation reaction of the resulting intermediate in the presence of sodium ethoxide in anhydrous toluene to afford the desired pyranoquinoline containing β-keto ester moiety. Keto-enol tautomerism of the compound thus obtained was investigated by spectroscopic methods.