Browsing by Author "Salunke, Deepak B."

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Design and Synthesis of New Biprivileged Molecular Scaffolds: Indolo-Fused Benzodiazepinyl/quinoxalinyl benzimidazoles
(2012-06-01)
Barve, Indrajeet J.
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Chen, Chan-Yu
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Salunke, Deepak B.
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Chung, Wen-Sheng
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Sun, Chung-Ming
The present article describes the design and synthesis of new biprivileged molecular scaffolds with diverse structural features. Commercially available, simple heterocyclic building blocks such as 4-fluoro-3-nitrobenzoic acid, 2-chloro-3-nitrobenzoic acid, and indoline were utilized for the synthesis of the novel heterocycles. PictetSpengler-type condensation was used as a key step to construct tetracyclic indolo-benzodiazepines and indolo-quinoxalines linked with substituted benzimidazoles. Analysis of single crystals of representative compounds showed that these molecular skeletons have the potential to present various substituents with distinct three-dimensional orientations.
Divergent Synthesis of Unsymmetrical Annulated Biheterocyclic Compound Libraries: Benzimidazole Linked Indolo-benzodiazepines/quinoxaline
(2011-07-01)
Chen, Li-Hsun
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Chang, Chia-Mao
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Salunke, Deepak B.
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Sun, Chung-Ming
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應用化學系
Diversity-oriented synthesis of novel benzimidazole linked indolo-benzodiazepine/quinoxaline ring systems using poly(ethylene glycol) as soluble polymer support is described. Corrunercially available 4-fluoro-3-nitrobenzoic acid and indoline were utilized for the construction of these annulated biheterocyclic compound libraries having multiple privileged structures with three-point structural diversity. A reagent based diversification approach coupled with the Pictet-Spengler-type condensation was used to construct the tetracydic indolo-benzodiazepines/quinoxalines on substituted benzimidazoles.
Multistep Microwave-Assisted Divergent Synthesis of Indolo-Fused Pyrazino-/Diazepinoquinoxalinones on PEG Support
(2010-05-21)
Lai, Jin-Ji
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Salunke, Deepak B.
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Sun, Chung-Ming
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應用化學系
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Department of Applied Chemistry
Synthesis of amino acid and indoline-substituted dinitrobenzene on a soluble polymer support (PEG) and its further reductive double-ring closure to afford structurally diverse indolo-fused pyrazino-/diazepinoquinoxalinones is described. Traceless synthesis of quinoxalinones coupled with application of the Pictet-Spengler-type condensation reaction furnished these novel scaffolds. These hitherto novel heterocycles are synthesized in shorter times under microwave irradiation conditions in comparison with that of classical reaction conditions.
Post-Pictet-Spengler Cyclization (PPSC): A Strategy to Synthesize Polycyclic beta-Carboline-Derived Natural Products and Biologically Active N-Heterocycles
(1970-01-01)
Singh, Rahul
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Kumar, Sunil
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Patil, Madhuri T.
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Sun, Chung-Ming
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Salunke, Deepak B.
Pictet-Spengler reaction is a typical condensation reaction of beta-arylethylamine or Tryptamine with an aldehyde or ketone followed by ring closure to generate tetrahydroisoquinoline (THIQ) and Tetrahydro-beta-carboline (TH beta C), respectively. Both these key skeletons represent huge range of structurally diverse naturally occurring isoquinoline and indole alkaloids. Nature has synthesized structurally complex Reserpine, Ajmalicine as well as other related alkaloids using various biosynthetic pathwaysviaPictet-Spengler reaction followed by post-Pictet-Spengler cyclization (PPSC) stratergy. This biosynthetic process is the short and reliable method to access diverse range of polycyclic heterocycles. Over the period of last sixty years, several researchers have synthesized complex alkaloids without highlighting the synthetic utility of the post-Pictet-Spengler cyclization strategy. We summarized the synthesis of numerous natural products and related natural product inspired heterocyclic scaffolds which follow the PPSC strategy to demonstrate its usefulness for the construction of diverse compound collection. 1. Introduction 2. beta-Carboline Fused Heterocycles Synthesized via post-Pictet-Spengler C1-N2 Cyclization 3. beta-Carboline Fused Heterocycles Synthesized via post Pictet-Spengler C1-N9 Cyclization 4. beta-Carboline Fused Heterocycles Synthesized via post-Pictet-Spengler C3-N2 Cyclization 5. beta-Carboline Fused Heterocycles Synthesized via post-Pictet-Spengler C1-C3 Cyclization 6. Conclusion
Regioselective Synthesis of Angular Isocoumarinselenazoles: A Benzoselenazole-directed, Site-specific, Ruthenium-catalyzed C(sp(2))-H Activation
(2018-03-01)
Dhole, Sandip
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Liao, Jen-Yu
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Kumar, Sunil
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Salunke, Deepak B.
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Sun, Chung-Ming
The synthesis of new, angular isocoumarinselenazoles is described, which involves the construction of 2-amino benzoselenazoles and their regioselective C2N-alkylation and alkyne insertion. An expeditious and metal-free synthesis of 2-aminobenzoselenazoles by the reaction of methyl 3-amino-4-fluorobenzoate and isoselenocyanates was achieved. Further N-alkylation of the 2-aminobenzoselenazoles resulted the formation of two regioisomers with different reactivities towards the alkyne insertion. The regioselective construction of the a-pyrone ring on the benzo[1,3-d] selenazole skeleton was achieved via a ruthenium (II)-catalyzed oxidative annulation. It is clear that the selenazole nitrogen plays an important role in the observed selectivity.
Soluble polymer supported divergent synthesis of tetracyclic benzene-fused pyrazino/diazepino indoles: an advanced synthetic approach to bioactive scaffolds
(2011)
Lin, Po-Tsung
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Salunke, Deepak B.
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Chen, Li-Hsun
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Sun, Chung-Ming
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應用化學系
The synthesis of indoline substituted nitrobenzene on a PEG support and its further elaboration to structurally diverse benzene-fused pyrazino/diazepino indoles is disclosed. A reagent based diversification approach coupled with Pictet-Spengler type condensation reactions furnished these fused polycyclic scaffolds. Microwave irradiation was used as a means of rate acceleration for soluble polymer-supported reactions. The efficiency of these fused heterocyclic molecules to inhibit the vascular endothelial growth factor receptor 3 (VEGFR-3) was examined in vitro using kinase receptor activation enzyme-linked immunosorbant assay (KIRA-ELISA). Based on the preliminary results obtained, a small set of potential drug candidates were identified as novel leads in this therapeutic area to be further explored as anti-metastatic agents.