Sandeep Chaudhary | NIPER (National Institute of Pharmaceutical Education & Research (original) (raw)
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Papers by Sandeep Chaudhary
![Research paper thumbnail of Microwave-assisted One-pot Efficient Synthesis of Functionalized 2-Oxo-2-phenylethylidenes-linked 2-Oxobenzo[1,4]oxazines and 2-Oxoquino[1,4]oxalines: Synthetic Applications, Antioxidant Activity, SAR and Cytotoxic Studies](https://attachments.academia-assets.com/119343194/thumbnails/1.jpg)
](Acta Chimica Slovenica, 2017
![Research paper thumbnail of {"__content__"=>"Discovery of C-3 Tethered 2-oxo-benzo[1,4]oxazines as Potent Antioxidants: Bio-Inspired Based Design, Synthesis, Biological Evaluation, Cytotoxic, and Molecular Docking Studies.", "i"=>{"__content__"=>"in Silico"}}](https://attachments.academia-assets.com/108840595/thumbnails/1.jpg)
](Frontiers in chemistry, 2018
The discovery of C-3 tethered 2-oxo-benzo[1,4]oxazines as potent antioxidants is disclosed. All t... more The discovery of C-3 tethered 2-oxo-benzo[1,4]oxazines as potent antioxidants is disclosed. All the analogs have been synthesized via "on water" ultrasound-assisted irradiation conditions in excellent yields (upto 98%). All the compounds have been evaluated for their antioxidant activities using DPPH free radical scavenging assay as well as FRAP assay. The result showed promising antioxidant activities having IC values in the range of 4.74 ± 0.08 to 92.20 ± 1.54 μg/mL taking ascorbic acid (IC = 4.57 μg/mL) as standard reference. In this study, compounds and , the most active compound of the series, showed IC values of 6.89 ± 0.07 μg/mL and 4.74 ± 0.08 μg/mL, respectively in comparison with ascorbic acid. In addition, the detailed SAR study shows that electron-withdrawing group increases antioxidant activity and vice versa. Furthermore, in the FRAP assay, eight compounds (, , , , , , , and ) were found more potent than standard reference BHT (C = 546.0 ± 13.6 μM). The preli...
![Research paper thumbnail of Organocatalytic Modified Guareschi–Thorpe Type Regioselective Synthesis: A Unified Direct Access to 5,6,7,8-Tetrahydroquinolines and Other Alicyclic[b]-Fused Pyridines](https://attachments.academia-assets.com/97073554/thumbnails/1.jpg)
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Tetrahedron Letters
ABSTRACT
Organic letters, Jan 2, 2015
New, highly stable tricyclic antitubercular ozonides 9 and 10 derived from artemisinin are report... more New, highly stable tricyclic antitubercular ozonides 9 and 10 derived from artemisinin are reported in 39 and 9% yields, respectively. The ozonide groups of 9 and 10 were found to be stable under strong basic and acidic conditions. The absolute configuration of ozonides 9 was confirmed by X-ray crystallography. Ozonide 10 shows promising antitubercular activity against M. tuberculosis H37Ra and M. tuberculosis H37Rv with MIC values of 0.39 and 3.12 μg/mL, respectively.
Tetrahedron Letters, 2015
ABSTRACT
Chemistry - A European Journal, 2013
An efficient enantioselective synthetic route to atorvastatin was developed based on a direct cat... more An efficient enantioselective synthetic route to atorvastatin was developed based on a direct catalytic asymmetric aldol reaction. The expensive chiral ligand used in the initial aldol reaction was readily recovered (91 %) and reused. Implementation of an oxy-Michael reaction for the construction of the syn-1,3-diol unit eliminated several redundant steps, allowing for rapid access to the common intermediate in six steps.
Natural product communications, 2008
From an acetone extract of the aerial parts of Tidestromia oblongifolia (Amaranthaceae), a new dr... more From an acetone extract of the aerial parts of Tidestromia oblongifolia (Amaranthaceae), a new drimane sesquiterpenoid bearing an 11,12,13-trihydroxydrimene skeleton (1) as well as the 11,12 acetonide of 1 were isolated. Three known stigmastane triterpenoids were also isolated. Structures were elucidated with the aid of 1D and 2D NMR spectroscopic techniques. The absolute configuration of 1 was confirmed by single-crystal x-ray crystallography. This is the first report on phytochemical constituents from any plant of the genus Tidestromia and is the first report of the occurrence of drimanes in the Amaranthaceae.
Tetrahedron, Jan 21, 2011
Representatives of the C-homoaporphine class of alkaloids have shown interesting biological activ... more Representatives of the C-homoaporphine class of alkaloids have shown interesting biological activities. To date the synthesis of these molecules has never been attempted via a direct arylation strategy. We report herein the first Pd-mediated intramolecular direct arylation in the synthesis of C-homoaporphines via the use of microwaves. Use of tricyclohexylphosphine tetrafluoroborate as ligand gave good percentage conversions and suppressed competing debromination with the substrates evaluated. This arylation strategy should be broadly useful in the synthesis of C-homoaporphine alkaloids as demonstrated herein in the synthesis of (±)-homonantenine.
ChemInform, 2010
3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information... more 3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full ...
ChemInform, 2009
3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information... more 3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full ...
Tetrahedron Letters, 2009
Journal of Medicinal Chemistry, 2006
A new series of ether derivatives of dihydroartemisinin have been prepared and evaluated for thei... more A new series of ether derivatives of dihydroartemisinin have been prepared and evaluated for their antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in mice by oral route. These new derivatives 7-17 are highly lipophilic (log P in the range of 5.51 to 7.19) as compared with beta-arteether (log P 3.84), and several of them are two- to four-fold more active than beta-arteether. Among the ether derivatives, alpha-isomers are more active than the beta-isomers. The ether derivatives 12alpha and 14alpha, the most active compounds of the series, provided 100% protection to infected mice at 12 mg/kgx4 days. In this model beta-arteether provides 100% and 20% protection at 48 mg/kgx4 days and 24 mg/kgx4 days, respectively.
Journal of Medicinal Chemistry, 2012
Artesunic acid 5, the hemisuccinate derivative of dihydroartemisinin 2, is the only clinically us... more Artesunic acid 5, the hemisuccinate derivative of dihydroartemisinin 2, is the only clinically useful water-soluble derivative of artemisinin 1. However, being a lactol ester, it is rapidly hydrolyzed back to dihydroartemisinin in aqueous alkaline solution, a reaction that seriously limits its utility. A new series of potentially more stable linker-based hemisuccinate derivatives 12a-i and 14a-c have been prepared. The process involved acid-catalyzed reaction of dihydroartemisinin with various diols and polyethylene glycols to give hydroxy-functionalized ethers 7a-i and 10a-c and their further derivatization to hemisuccinate esters 12a-i and 14a-c. Both the hydroxy-functionalized ethers 7a-i and 10a-c and their hemisuccinate derivatives 12a-i and 14a-c have been assessed for antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in Swiss mice. Several of these hemisuccinate derivatives have shown very promising activity. Hemisuccinate derivatives 12f and 12i, the two most active compounds of the series, provided 100% protection to malaria-infected mice at 24 mg/kg × 4 days and therefore are twice as potent as artesunic acid, which provides a similar level of protection at 48 mg/kg × 4 days.
Bioorganic & Medicinal Chemistry Letters, 2009
Bioorganic & Medicinal Chemistry Letters, 2008
Bioorganic & Medicinal Chemistry Letters, 2011
Acta Chimica Slovenica, 2017
Frontiers in chemistry, 2018
The discovery of C-3 tethered 2-oxo-benzo[1,4]oxazines as potent antioxidants is disclosed. All t... more The discovery of C-3 tethered 2-oxo-benzo[1,4]oxazines as potent antioxidants is disclosed. All the analogs have been synthesized via "on water" ultrasound-assisted irradiation conditions in excellent yields (upto 98%). All the compounds have been evaluated for their antioxidant activities using DPPH free radical scavenging assay as well as FRAP assay. The result showed promising antioxidant activities having IC values in the range of 4.74 ± 0.08 to 92.20 ± 1.54 μg/mL taking ascorbic acid (IC = 4.57 μg/mL) as standard reference. In this study, compounds and , the most active compound of the series, showed IC values of 6.89 ± 0.07 μg/mL and 4.74 ± 0.08 μg/mL, respectively in comparison with ascorbic acid. In addition, the detailed SAR study shows that electron-withdrawing group increases antioxidant activity and vice versa. Furthermore, in the FRAP assay, eight compounds (, , , , , , , and ) were found more potent than standard reference BHT (C = 546.0 ± 13.6 μM). The preli...
Tetrahedron Letters
ABSTRACT
Organic letters, Jan 2, 2015
New, highly stable tricyclic antitubercular ozonides 9 and 10 derived from artemisinin are report... more New, highly stable tricyclic antitubercular ozonides 9 and 10 derived from artemisinin are reported in 39 and 9% yields, respectively. The ozonide groups of 9 and 10 were found to be stable under strong basic and acidic conditions. The absolute configuration of ozonides 9 was confirmed by X-ray crystallography. Ozonide 10 shows promising antitubercular activity against M. tuberculosis H37Ra and M. tuberculosis H37Rv with MIC values of 0.39 and 3.12 μg/mL, respectively.
Tetrahedron Letters, 2015
ABSTRACT
Chemistry - A European Journal, 2013
An efficient enantioselective synthetic route to atorvastatin was developed based on a direct cat... more An efficient enantioselective synthetic route to atorvastatin was developed based on a direct catalytic asymmetric aldol reaction. The expensive chiral ligand used in the initial aldol reaction was readily recovered (91 %) and reused. Implementation of an oxy-Michael reaction for the construction of the syn-1,3-diol unit eliminated several redundant steps, allowing for rapid access to the common intermediate in six steps.
Natural product communications, 2008
From an acetone extract of the aerial parts of Tidestromia oblongifolia (Amaranthaceae), a new dr... more From an acetone extract of the aerial parts of Tidestromia oblongifolia (Amaranthaceae), a new drimane sesquiterpenoid bearing an 11,12,13-trihydroxydrimene skeleton (1) as well as the 11,12 acetonide of 1 were isolated. Three known stigmastane triterpenoids were also isolated. Structures were elucidated with the aid of 1D and 2D NMR spectroscopic techniques. The absolute configuration of 1 was confirmed by single-crystal x-ray crystallography. This is the first report on phytochemical constituents from any plant of the genus Tidestromia and is the first report of the occurrence of drimanes in the Amaranthaceae.
Tetrahedron, Jan 21, 2011
Representatives of the C-homoaporphine class of alkaloids have shown interesting biological activ... more Representatives of the C-homoaporphine class of alkaloids have shown interesting biological activities. To date the synthesis of these molecules has never been attempted via a direct arylation strategy. We report herein the first Pd-mediated intramolecular direct arylation in the synthesis of C-homoaporphines via the use of microwaves. Use of tricyclohexylphosphine tetrafluoroborate as ligand gave good percentage conversions and suppressed competing debromination with the substrates evaluated. This arylation strategy should be broadly useful in the synthesis of C-homoaporphine alkaloids as demonstrated herein in the synthesis of (±)-homonantenine.
ChemInform, 2010
3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information... more 3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full ...
ChemInform, 2009
3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information... more 3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full ...
Tetrahedron Letters, 2009
Journal of Medicinal Chemistry, 2006
A new series of ether derivatives of dihydroartemisinin have been prepared and evaluated for thei... more A new series of ether derivatives of dihydroartemisinin have been prepared and evaluated for their antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in mice by oral route. These new derivatives 7-17 are highly lipophilic (log P in the range of 5.51 to 7.19) as compared with beta-arteether (log P 3.84), and several of them are two- to four-fold more active than beta-arteether. Among the ether derivatives, alpha-isomers are more active than the beta-isomers. The ether derivatives 12alpha and 14alpha, the most active compounds of the series, provided 100% protection to infected mice at 12 mg/kgx4 days. In this model beta-arteether provides 100% and 20% protection at 48 mg/kgx4 days and 24 mg/kgx4 days, respectively.
Journal of Medicinal Chemistry, 2012
Artesunic acid 5, the hemisuccinate derivative of dihydroartemisinin 2, is the only clinically us... more Artesunic acid 5, the hemisuccinate derivative of dihydroartemisinin 2, is the only clinically useful water-soluble derivative of artemisinin 1. However, being a lactol ester, it is rapidly hydrolyzed back to dihydroartemisinin in aqueous alkaline solution, a reaction that seriously limits its utility. A new series of potentially more stable linker-based hemisuccinate derivatives 12a-i and 14a-c have been prepared. The process involved acid-catalyzed reaction of dihydroartemisinin with various diols and polyethylene glycols to give hydroxy-functionalized ethers 7a-i and 10a-c and their further derivatization to hemisuccinate esters 12a-i and 14a-c. Both the hydroxy-functionalized ethers 7a-i and 10a-c and their hemisuccinate derivatives 12a-i and 14a-c have been assessed for antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in Swiss mice. Several of these hemisuccinate derivatives have shown very promising activity. Hemisuccinate derivatives 12f and 12i, the two most active compounds of the series, provided 100% protection to malaria-infected mice at 24 mg/kg × 4 days and therefore are twice as potent as artesunic acid, which provides a similar level of protection at 48 mg/kg × 4 days.
Bioorganic & Medicinal Chemistry Letters, 2009
Bioorganic & Medicinal Chemistry Letters, 2008
Bioorganic & Medicinal Chemistry Letters, 2011