A versatile synthetic route to chiral quinoxaline derivatives from amino acids precursors (original) (raw)
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A versatile synthetic route to chiral quinoxaline derivatives from amino
The synthesis of N-protected L-amino acid (3-benzylquinoxalin-2-yl) hydrazide derivatives is reported here. 3-Benzyl-2-hydrazinoquinoxaline was prepared and then coupled with N-Boc-L-amino acids including; Alanine, Valine, Leucine, Phenylalanine, Tyrosine, Serine and Proline in the presence of HBTU as a coupling reagent to provide the expected product with high yield and purity. The products were deprotected by p-toluenesulphonic acid in acetonitrile and then the tosylate salts were evaluated for antibacterial and antifungal activity.
Journal of Heterocyclic Chemistry, 2017
Alkylation of quinoxaline scaffold 1 in the presence of K 2 CO 3 preferred N-alkylation than O-alkylation. Quinoxaline hydrazide 6 was successfully coupled with various amino acids, esters, and amines via azide-coupling method. New heterocyclic compounds containing quinoxaline linked to 1,3,4-oxadiazolethione or pyrazole were obtained from cyclization of 6 with CS 2 and acetylacetone, respectively. A series of hydrazide Schiff's bases were formed from hydrazide 6 by condensation with a set of aldehydes and ketones. NMR spectroscopy and mass spectrometry were used for structure elucidation of new compounds. The antimicrobial activity of the synthesized compounds was investigated toward two wild-type bacterial strains (Staphylococcus aureus and Escherichia coli) and two fungal species (Alternaria brassicicola and Fusarium oxysporum). Four compounds displayed a significant activity toward S. aureus. The ester 4 showed higher activity than the standard drugs, which make it a promising lead compound.
Medicinal Chemistry Research, 2018
Newcastle disease virus is the most devastating virus in poultry industry. It can eradicate the entire poultry flocks once infected. This study is aimed to investigate the antiviral efficacy of novel phosphorylated analogues of the drug abacavir (ABC) against Newcastle disease virus (NDV). About 16 analogues of ABC were designed and docking was performed against fusion protein of NDV. Three compounds were identified and selected for synthesis and biological evaluation based on binding affinity and docking scores. The compounds were synthesized and characterized by IR, 1 H, 13 C, 31 P and CHN analysis and mass spectra. These compounds were tested for antiviral efficacy against NDVinfected DF-1 cells. Compound ABC-1 had shown potent antiviral activity as evidenced by significant reduction in plaque units and cytopathic effect. Therefore, ABC-1 was selected to test for NDV-infected chicken survival rate. Effective dose 50 concentrations were determined for ABC-1. Antioxidant enzyme levels in brain, liver and lung tissues were estimated. Superoxide dismutase and catalase were significantly raised and lipid peroxidation and HA titer levels were decreased upon treatment with 2 mg/kg body weight ABC-1. Histopathological modifications were also restored in the ABC-1-treated group. These findings demonstrated ABC-1 as a potential antiviral agent against NDV in chicken.
Synthetic Development of Antimicrobial Novel Quinoxaline Derivatives
3.2.3. N-(4-Chlorophe nyl)-2,3-diphenylquinoxaline-6-sulfonamide (c): 0.65 g of 4-Chloro aniline was refluxed with 1.9 g of 2, 3-Diphenylquinoxaline-6-sulfonylchloride and 50 ml of 10% aq. NaOH solution for 1.30 hrs. Then reaction mixture was po ured into 10 ml. cold water and stirred until product crystallized then product was filtered and recrystalized by ethanol.
Synthesis and Antimicrobial Activity of Some Quinoxaline Derivatives
2013
A series of quinoxaline derivatives were synthesized by doing molecular modifications at C-3 methyl group of 2-hydroxy-3-methylquinoxaline nucleus. The synthesis was initiated by bromination followed by attachment of p-hydroxy bezaldehydes to 3-methyl group to synthesize 3(4-formyl phenoxymethyl)-quinoxaline-(1 H)-2-one as new intermediate and condense it with substituted aromatic amines to afford the synthesis of Schiff bases of 3-methylquinoxalin-2(1 H)-one. The new compounds (GG1, GG2, GG3, GG4 and GG5) have been synthesized by treating o-phenylene- diamine with ethyl pyruvate to yield 3-methylquinoxaline 2-one, which on bromination afforded the synthesis of 3-bromomethyl quinoxaline-2-one. Finally 3-bromomethyl quinoxaline-2-one was treated with 4-hydroxy benzaldehyde to yield the synthesis of 3-(-4-formyl phenoxy methyl)-quinoxalin 2(1 H)-one (GG1), which was treated with different substituted aromatic amines to yield the synthesis of 3-((4-(substituted-phenylimino)-methyl)-phe...
Synthesis of Quinoline Analogues as Anti-microbial Agents
2015
Various substituted Quinoline containing different functional group have been synthesized by conventional method. The quinoline derivative is synthesized by using 8-hydroxy quinoline) was first treated with ethyl chloroacetate to form ester intermediate which was subsequently treated with Hydrazine Hydrate result into formation of Hydrazone derivative then this intermediate was made to react with substituted benzoic acid. The final structures have been established on the basis of their chemical analysis and spectral data. Final compounds were further evaluated for in-vitro anti-microbial activity using standards.
Aims: This aims of this study was to synthesis new quinoxaline-based heterocycles and study its antibacterial properties. Objective: This study was designed to synthesis some 3-methyl-6-nitroquinoxaline-2-one with hydrazine moiety, characterize the synthesized compounds, and study their antibacterial properties on some bacterial strains. Materials and Methods: Six 3-methylquinoxaline-2-hydrazone derivatives were synthesized by reacting 2-hydrazinyl-3-methyl-6-nitroquinoxaline with various substituted acetophenones. The hydrazones were screened for their potential antibacterial properties. Results: All the test compounds were found to possessed promising antibacterial properties against a panel of bacterial strains screened for this study. The MIC values exhibited by these compounds ranged between 0.0313 and 0.250 mg/mL. The lowest MBC of the compounds against the test organism was 0.0625 mg/mL while the highest MBC was 0.250 mg/mL. Discussion and Conclusion: The study concluded that all the compounds exhibited appreciable bactericidal effects against all the bacterial strains, which is an indication that such synthetic Original Research Article
Synthesis and Antimicrobial Activity of Some New Quinoline Derivatives
2012
Two series of novel quinoline derivatives; oxadiazolyl and thiadiazolyl quinolines were prepared and evaluated for their antimicrobial activities. The first series; 5-(2-aryl-6-substituted-4-quinolyl)-1.3,4-oxadiazol-2-amines (Va-g) was synthesized by cyclization of the key intermediate thiosemicarbazides (IV1-7). The second one; 5-(2-aryl-6-substituted-4-quinoly!)-1,3.4- thiadiazol-2-amines (VI a.c.f.g) was synthesized through cyclization of the key intermediate quinoline-4-carboxylic acids (I1-7) or from the synthetically accessible thiosemicarbazides (IV1-7).The target oxadiazole and thiadiazole derivatives were evaluated against Gram positive, Gram negative bacteria and fungi. The obtained results showed that the 1,3,4-thiadiazoles VI 4,8 exhibited the most potent antibacterial activity with MIC values of 4 µg/ml.
Synthesis and Characterization of New Quinazolines as Potential Antimicrobial Agents
ChemInform, 2007
Ethyl 4-[2-(2-chlorophenyl)-4-oxo-3-hydroquinazolin-3yl]benzoate 1 which reacts with hydrazine hydrate in presence of methanol resulted into N-amino{4-[2-(2-chlorophenyl)-4-oxo(3hydroquinazolin-3-yl)phenyl}carboxamide 2. Compound 2 on treatment with aryl isothiocyanates in presence of acetone is converted into aryl-N-{[({4-[2-(2-chlorophenyl)-4-oxo(3-hydroquinazolin-3-yl)]phenyl}carbonylamino)amino]thioxo methyl}amides 3. Compound 3, in presence of sulphuric acid has yielded aryl-N-(5-{4-[2-(2-chlorophenyl)-4-oxo(3-hydroquinazolin-3-yl)]-phenyl}(1,3,4,thiadiazol-2-yl))amides 4a-l. Newly synthesized compounds 4a-l have been screened for their antibacterial and antifungal activities on Eschericia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus pyogenes, C. albicans, A. niger and A. clavatus.