The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
K C Majumdar - One of the best experts on this subject based on the ideXlab platform.
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bf3 oet2 mediated 1 3 hydride shift followed by 6π electrocyclization an efficient route for the synthesis of pyridopyrimidine pyranoquinoline and phenanthroline derivatives
ChemInform, 2012Co-Authors: K C Majumdar, Sudipta Ponra, Raj Kumar NandiAbstract:A variety of potentially bioactive pyridopyrimidine (III), (VI), pyranoquinoline and phenanthroline derivatives (VIII) is prepared by BF3·OEt2-catalyzed cyclization of heterocycle-based aminopentadienes (I) and (VII) with aromatic aldehydes as well as formaldehyde.
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bf3 oet2 mediated 1 3 hydride shift followed by 6π electrocyclization an efficient route for the synthesis of pyridopyrimidine pyranoquinoline and phenanthroline derivatives
European Journal of Organic Chemistry, 2011Co-Authors: K C Majumdar, Sudipta Ponra, Raj Kumar NandiAbstract:The synthesis of pyridopyrimidine, pyranoquinoline, and phenanthroline derivatives can be easily and efficiently accomplished by the direct reaction of a 1-aminopenta-1,4-diene fragment, an aromatic aldehyde, and BF 3 ·OEt 2 in the absence of any metal catalyst. The notable features of this procedure are mild reaction conditions, good to high yields, and operational simplicity.
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palladium catalyzed intramolecular arylation of pyrimidines a novel and expedient avenue to benzannulated Pyridopyrimidines
ChemInform, 2009Co-Authors: K C Majumdar, Biswajit Sinha, Pradip K Maji, Shital K ChattopadhyayAbstract:Abstract A new efficient protocol for the synthesis of benzannulated pyrido[2,3-d]- and pyrido[3,2-d]pyrimidines has been successfully accomplished via the palladium-catalyzed intramolecular arylation of C–H bond of pyrimidine moiety. The methodology has also been extended to the synthesis of pyrimido[5,4,-c]isoquinoline-2,4,6(1H,3H,5H)-trione derivatives in excellent yields.
Jeff B Smaill - One of the best experts on this subject based on the ideXlab platform.
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tyrosine kinase inhibitors 15 4 phenylamino quinazoline and 4 phenylamino pyrido d pyrimidine acrylamides as irreversible inhibitors of the atp binding site of the epidermal growth factor receptor
Journal of Medicinal Chemistry, 1999Co-Authors: Jeff B Smaill, Alexander J Bridges, Hairong Zhou, Dennis Joseph Mcnamara, Ellen Myra Dobrusin, H Hollis D Showalter, William A. Denny, Brian D Palmer, Gordon W. Rewcastle, Thomas R WintersAbstract:A series of 6- and 7-acrylamide derivatives of the 4-(phenylamino)quinazoline and -pyridopyrimidine classes of epidermal growth factor receptor (EGFR) inhibitors were prepared from the corresponding amino compounds by reaction with either acryloyl chloride/base or acrylic acid/1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. All of the 6-acrylamides, but only the parent quinazoline 7-acrylamide, were irreversible inhibitors of the isolated enzyme, confirming that the former are better-positioned, when bound to the enzyme, to react with the critical cysteine-773. Quinazoline, pyrido[3,4-d]pyrimidine, and pyrido[3,2-d]pyrimidine 6-acrylamides were all irreversible inhibitors and showed similar high potencies in the enzyme assay (likely due to titration of the available enzyme). However the pyrido[3,2-d]pyrimidine analogues were 2−6-fold less potent than the others in a cellular autophosphorylation assay for EGFR in A431 cells. The quinazolines were generally less potent overall toward inhibition...
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tyrosine kinase inhibitors 15 4 phenylamino quinazoline and 4 phenylamino pyrido d pyrimidine acrylamides as irreversible inhibitors of the atp binding site of the epidermal growth factor receptor
Journal of Medicinal Chemistry, 1999Co-Authors: Jeff B Smaill, Alexander J Bridges, Hairong Zhou, Dennis Joseph Mcnamara, Ellen Myra Dobrusin, William A. Denny, Brian D Palmer, Gordon W. Rewcastle, Howard Daniel Hollis Showalter, Roy Thomas WintersAbstract:A series of 6- and 7-acrylamide derivatives of the 4-(phenylamino)quinazoline and -pyridopyrimidine classes of epidermal growth factor receptor (EGFR) inhibitors were prepared from the corresponding amino compounds by reaction with either acryloyl chloride/base or acrylic acid/1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. All of the 6-acrylamides, but only the parent quinazoline 7-acrylamide, were irreversible inhibitors of the isolated enzyme, confirming that the former are better-positioned, when bound to the enzyme, to react with the critical cysteine-773. Quinazoline, pyrido[3,4-d]pyrimidine, and pyrido[3,2-d]pyrimidine 6-acrylamides were all irreversible inhibitors and showed similar high potencies in the enzyme assay (likely due to titration of the available enzyme). However the pyrido[3,2-d]pyrimidine analogues were 2-6-fold less potent than the others in a cellular autophosphorylation assay for EGFR in A431 cells. The quinazolines were generally less potent overall toward inhibition of heregulin-stimulated autophosphorylation of erbB2 (in MDA-MB-453-cells), whereas the Pyridopyrimidines were equipotent. Selected compounds were evaluated in A431 epidermoid and H125 non-small-cell lung cancer human tumor xenografts. The compounds showed better activity when given orally than intraperitoneally. All showed significant tumor growth inhibition (stasis) over a dose range. The poor aqueous solubility of the compounds was a drawback, requiring formulation as fine particulate emulsions.
Terry L Bowlin - One of the best experts on this subject based on the ideXlab platform.
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structure activity relationships of a novel pyranopyridine series of gram negative bacterial efflux pump inhibitors
Bioorganic & Medicinal Chemistry, 2015Co-Authors: Son T Nguyen, Steven M Kwasny, Xiaoyuan Ding, Steven C Cardinale, Courtney T Mccarthy, Hongsuk Kim, Hiroshi Nikaido, Norton P Peet, John D Williams, Terry L BowlinAbstract:Recently we described a novel pyranopyridine inhibitor (MBX2319) of RND-type efflux pumps of the Enterobacteriaceae. MBX2319 (3,3-dimethyl-5-cyano-8-morpholino-6-(phenethylthio)-3,4-dihydro-1H-pyrano[3,4-c]pyridine) is structurally distinct from other known Gram-negative efflux pump inhibitors (EPIs), such as 1-(1-naphthylmethyl)-piperazine (NMP), phenylalanylarginine-β-naphthylamide (PAβN), D13-9001, and the pyridopyrimidine derivatives. Here, we report the synthesis and biological evaluation of 60 new analogs of MBX2319 that were designed to probe the structure activity relationships (SARs) of the pyranopyridine scaffold. The results of these studies produced a molecular activity map of the scaffold, which identifies regions that are critical to efflux inhibitory activities and those that can be modified to improve potency, metabolic stability and solubility. Several compounds, such as 22d–f, 22i and 22k, are significantly more effective than MBX2319 at potentiating the antibacterial activity of levofloxacin and piperacillin against Escherichia coli.
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structure activity relationships of a novel pyranopyridine series of gram negative bacterial efflux pump inhibitors
Bioorganic & Medicinal Chemistry, 2015Co-Authors: Son T Nguyen, Steven M Kwasny, Xiaoyuan Ding, Steven C Cardinale, Courtney T Mccarthy, Hiroshi Nikaido, Norton P Peet, John D Williams, Terry L Bowlin, Timothy J OppermanAbstract:Recently we described a novel pyranopyridine inhibitor (MBX2319) of RND-type efflux pumps of the Enterobacteriaceae. MBX2319 (3,3-dimethyl-5-cyano-8-morpholino-6-(phenethylthio)-3,4-dihydro-1H-pyrano[3,4-c]pyridine) is structurally distinct from other known Gram-negative efflux pump inhibitors (EPIs), such as 1-(1-naphthylmethyl)-piperazine (NMP), phenylalanylarginine-β-naphthylamide (PAβN), D13-9001, and the pyridopyrimidine derivatives. Here, we report the synthesis and biological evaluation of 60 new analogs of MBX2319 that were designed to probe the structure activity relationships (SARs) of the pyranopyridine scaffold. The results of these studies produced a molecular activity map of the scaffold, which identifies regions that are critical to efflux inhibitory activities and those that can be modified to improve potency, metabolic stability and solubility. Several compounds, such as 22d–f, 22i and 22k, are significantly more effective than MBX2319 at potentiating the antibacterial activity of levofloxacin and piperacillin against Escherichia coli.
Raj Kumar Nandi - One of the best experts on this subject based on the ideXlab platform.
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bf3 oet2 mediated 1 3 hydride shift followed by 6π electrocyclization an efficient route for the synthesis of pyridopyrimidine pyranoquinoline and phenanthroline derivatives
ChemInform, 2012Co-Authors: K C Majumdar, Sudipta Ponra, Raj Kumar NandiAbstract:A variety of potentially bioactive pyridopyrimidine (III), (VI), pyranoquinoline and phenanthroline derivatives (VIII) is prepared by BF3·OEt2-catalyzed cyclization of heterocycle-based aminopentadienes (I) and (VII) with aromatic aldehydes as well as formaldehyde.
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bf3 oet2 mediated 1 3 hydride shift followed by 6π electrocyclization an efficient route for the synthesis of pyridopyrimidine pyranoquinoline and phenanthroline derivatives
European Journal of Organic Chemistry, 2011Co-Authors: K C Majumdar, Sudipta Ponra, Raj Kumar NandiAbstract:The synthesis of pyridopyrimidine, pyranoquinoline, and phenanthroline derivatives can be easily and efficiently accomplished by the direct reaction of a 1-aminopenta-1,4-diene fragment, an aromatic aldehyde, and BF 3 ·OEt 2 in the absence of any metal catalyst. The notable features of this procedure are mild reaction conditions, good to high yields, and operational simplicity.
Oktay Arslan - One of the best experts on this subject based on the ideXlab platform.
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synthesis of carbazole bearing pyridopyrimidine substituted sulfonamide derivatives and studies their carbonic anhydrase enzyme activity
Journal of Biochemical and Molecular Toxicology, 2019Co-Authors: Arleta Rifatinixha, Mustafa Arslan, Nahit Gencer, Kubra Cikrikici, Basak Gokce, Oktay ArslanAbstract:The synthesis of carbazole containing pyridopyrimidine-substituted sulfonamide derivatives (3a-i) and their inhibitory effects on human carbonic anhydrase (hCA) I and II were studied. Spectral data and elemental analysis confirmed the structures of the compounds synthesized. The results show that all the synthesized compounds inhibited the CA I and II activities. Among them, 3a was found to be the most active ( K i : 14 µM) for hCA I and 3f ( K i : 126 µM) for hCA II.
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development of carbazole bearing pyridopyrimidine substituted urea thiourea as polyphenol oxidase inhibitors synthesis biochemistry and theoretical studies
Archives of Physiology and Biochemistry, 2019Co-Authors: Arleta Rifati Nixha, Oktay Arslan, Nahit Gencer, Adem Ergun, Mustafa ArslanAbstract:Polyphenol oxidase (Tyrosinase, PPO) has received considerable attention, since it is the key enzyme in melanin biosynthesis. In this study, we investigated prepared novel carbazole-containing pyridopyrimidine-substituted with urea and thiourea derivatives and their PPO activities on the diphenolase activity of banana tyrosinase. The structures of the compounds synthesized were confirmed by 1 H NMR, 13 C NMR, FTIR and elemental analysis. PPO enzyme was purified from banana on an affinity gel comprised of Sepharose 4B-L-tyrosine-p-amino benzoic acid. For evaluating the enzyme activity, the synthesised compounds were subjected to tyrosinase inhibition assay using catechol as substrate. While some of the compounds (6, 7, 8f, 8h, 8i, 8j) showed enzyme inhibitor effect, some of them (8a, 8b, 8c, 8d, 8e, 8g, 8k) activated the PPO enzyme activity. Gaussian software was used for the molecular calculations to explain the results for the prepared compounds.
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Development of carbazole-bearing pyridopyrimidine-substituted urea/thiourea as polyphenol oxidase inhibitors: synthesis, biochemistry, and theoretical studies
'Informa UK Limited', 2019Co-Authors: Arleta Rifati Nixha, Nahit Gencer, Oktay Arslan, Adem Ergun, Arslan MustafaAbstract:Polyphenol oxidase (Tyrosinase, PPO) has received considerable attention, since it is the key enzyme in melanin biosynthesis. In this study, we investigated prepared novel carbazole-containing pyridopyrimidine-substituted with urea and thiourea derivatives and their PPO activities on the diphenolase activity of banana tyrosinase. The structures of the compounds synthesized were confirmed by 1 H NMR, 13 C NMR, FTIR and elemental analysis. PPO enzyme was purified from banana on an affinity gel comprised of Sepharose 4B-L-tyrosine-p-amino benzoic acid. For evaluating the enzyme activity, the synthesised compounds were subjected to tyrosinase inhibition assay using catechol as substrate. While some of the compounds (6, 7, 8f, 8h, 8i, 8j) showed enzyme inhibitor effect, some of them (8a, 8b, 8c, 8d, 8e, 8g, 8k) activated the PPO enzyme activity. Gaussian software was used for the molecular calculations to explain the results for the prepared compounds
