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Gurpinder Singh

Bio: Gurpinder Singh is an academic researcher from Guru Nanak Dev University. The author has contributed to research in topics: Nitrone & Crotyl. The author has an hindex of 7, co-authored 15 publications receiving 224 citations.

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Journal ArticleDOI
TL;DR: The compounds displayed promising anticancer activity under these test systems and shall serve as useful 'leads' for further design.

88 citations

Journal ArticleDOI
TL;DR: The bivariate correlation results revealed that any of the two radiographic techniques (IOPA and OPG) can be used for analysis of the regenerative therapy in IBDs.
Abstract: Objective: The primary objective of this study was to compare clinically and radiographically the efficacy of autologous platelet rich fibrin (PRF) and autogenous bone graft (ABG) obtained using bone scrapper in the treatment of intrabony periodontal defects. Materials and Methods: Thirty-eight intrabony defects (IBDs) were treated with either open flap debridement (OFD) with PRF or OFD with ABG. Clinical parameters were recorded at baseline and 6 months postoperatively. The defect-fill and defect resolution at baseline and 6 months were calculated radiographically (intraoral periapical radiographs [IOPA] and orthopantomogram [OPG]). Results: Significant probing pocket depth (PPD) reduction, clinical attachment level (CAL) gain, defect fill and defect resolution at both PRF and ABG treated sites with OFD was observed. However, inter-group comparison was non-significant (P > 0.05). The bivariate correlation results revealed that any of the two radiographic techniques (IOPA and OPG) can be used for analysis of the regenerative therapy in IBDs. Conclusion: The use of either PRF or ABG were effective in the treatment of three wall IBDs with an uneventful healing of the sites.

53 citations

Journal ArticleDOI
TL;DR: Substituted 3-formylchromones react with 2-phenyl-4-dimethylamino-1-thia-3-azabuta-1,3-diene ( 4 ) or thio-benzamide ( 7 ) by heating their toluene solution in a sealed tube to give novel substituted 3-(5phenyl)-3 H -[1,2,4]dithiazol-3yl)chromen-4ones ( 6a − e ) in high yields as discussed by the authors.

23 citations

Journal ArticleDOI
TL;DR: In contrast to the reported facile intramolecular 1,3-dipolar cycloadditions of in-situ generated nitrone on heterocyclic systems, reactions of 2-(N-allyl/crotyl/cinnamyl-anilino)-3-formylchromones with N-phenyl-/methylhydroxylamine under comparable conditions, afford fused isoxazolidines only in low to moderate yields; the corresponding amides derived from rearrangement of in situ generated nitrones are formed as major products RE

21 citations

Journal ArticleDOI
TL;DR: In this article, a stereoselective 1,3-dipolar cycloadditions of C -(3-indolyl)- N -phenylnitrone (10) with different mono-substituted, disubstitized and cyclic dipolarophiles under mono-mode microwave irradiation were carried out to obtain substituted 3-(indol-3′-3-yl)- N-phenyl-isoxazolidines (16−22).

17 citations


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TL;DR: This work was supported by the Foundation for Science and Technology (FCT), Portugal (projects PTDC/QUI-QUI/113687/2009 and PEst-C/QUI/UI0081/2013) and SFRH/BD/61262/2009.
Abstract: This work was supported by the Foundation for Science and Technology (FCT), Portugal (projects PTDC/QUI-QUI/113687/2009 and PEst-C/QUI/UI0081/2013). A.G. (SFRH/BD/43531/2008) and M.J.M. (SFRH/BD/61262/2009) thank FCT for grants.

514 citations

Journal ArticleDOI
TL;DR: The present review focuses on the pharmacological profile of chromone derivatives in the current literature with an update of recent research findings on this nucleus and the perspectives that they hold for future research.

331 citations

Journal ArticleDOI
TL;DR: Corey et al. as discussed by the authors provided an update on the principal developments of catalytic non-enzymatic kinetic resolution (KR) covering the literature since 2004, which is the most important industrial approach to the synthesis of chiral compounds.
Abstract: While tremendous advances have been made in asymmetric synthesis, the resolution of racemates is still the most important industrial approach to the synthesis of chiral compounds. The use of enzymes for the kinetic resolution (KR) of racemic substrates to afford enantiopure compounds in high enantioselectivity and good yield has long been a popular strategy in synthesis. However, transition metal-mediated and more recently organocatalyzed KRs have gained popularity within the synthetic community over the last two decades due to the progress made in the development of chiral catalysts for asymmetric reactions. Many catalytic non-enzymatic procedures have been developed providing high enantioselectivity and yield for both products and recovered starting materials. Indeed, the non-enzymatic KR of racemic compounds based on the use of a chiral catalyst is presently an area of great importance in asymmetric organic synthesis. The goal of this review is to provide an update on the principal developments of catalytic non-enzymatic KR covering the literature since 2004. This review is subdivided into seven sections, according to the different types of compounds that have been resolved through catalytic non-enzymatic KR, such as alcohols, epoxides, amines, alkenes, carbonyl derivatives, sulfur compounds and ferrocenes. Abbreviations: Ac: acetyl; acac: acetylacetone; AQN: anthraquinone; Ar: aryl; Atm: atmosphere; BINAM: 1,1′-binaphthalenyl-2,2′-diamine; BINAP: 2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl; BINEPINE: phenylbinaphthophosphepine; BINOL: 1,1′-bi-2-naphthol; Bmim: 1-butyl-3-methylimidazolium; Bn: benzyl; Boc: tert-butoxycarbonyl; Box: bisoxazoline; BSA: bis(trimethylsilyl)acetamide; Bu: butyl; Bz: benzoyl; c: cyclo; CBS: Corey–Bakshi–Shibata; Cbz: benzyloxycarbonyl; COD: cyclooctadiene; COE: cyclooctene; Cy: cyclohexyl; Dba: (E,E)-dibenzylideneacetone; DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene; DCC: N,N′-dicyclohexylcarbodiimide; de: diastereomeric excess; DEAD: diethyl azodicarboxylate; Dec: decanyl; DHQD: dihydroquinidine; Difluorphos: 5,5′-bis(diphenylphosphino)-2,2,2′,2′-tetrafluoro-4,4′-bi-1,3-benzodioxole; DIPEA: diisopropylethylamine: DKR: dynamic kinetic resolution; DMAP: 4-dimethylaminopyridine; DMSO: dimethyl sulfoxide; DNA: deoxyribonucleic acid; DOSP: N-(dodecylbenzenesulfonyl)prolinate; DTBM: di-tert-butylmethoxy; ee: enantiomeric excess; Et: ethyl; equiv.: equivalent; Fu: furyl; Hex: hexyl; HIV: human immunodeficiency virus; HMDS: hexamethyldisilazide; KR: kinetic resolution; L: ligand; LDA: lithium diisopropylamide; MAO: methylaluminoxane; Me: methyl; Ms: mesyl; MTBE: methyl tert-butyl ether; Naph: naphthyl; nbd: norbornadiene; NBS: N-bromosuccinimide; NIS: N-iodosuccinimide; Pent: pentyl; Ph: phenyl; Piv: pivaloyl; PMB: p-methoxybenzoyl; Pr: propyl Py: pyridyl; r.t.: room temperature; s: selectivity factor; Segphos: 5,5′-bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole; (S,S′,R,R′)-Tangphos: (1S,1S′,2R,2R′)-1,1′-di-tert-butyl-(2,2′)-diphospholane; TBS: tert-butyldimethylsilyl; TBDPS: tert-butyldiphenylsilyl; TCCA: trichloroisocyanuric acid ; TEA: triethylamine; TEMPO: tetramethylpentahydropyridine oxide; THF: tetrahydrofuran; Thio: thiophene; Tf: trifluoromethanesulfonyl; TMS: trimethylsilyl; Tol: tolyl; Ts: 4-toluenesulfonyl (tosyl)

258 citations

Journal ArticleDOI
TL;DR: An overview of therapies and biomaterials used for alveolar bone engineering around teeth and implants and for implant site development are presented, with emphasis on most recent findings and future directions.
Abstract: The balance between bone resorption and bone formation is vital for maintenance and regeneration of alveolar bone and supporting structures around teeth and dental implants. Tissue regeneration in the oral cavity is regulated by multiple cell types, signaling mechanisms, and matrix interactions. A goal for periodontal tissue engineering/regenerative medicine is to restore oral soft and hard tissues through cell, scaffold, and/or signaling approaches to functional and aesthetic oral tissues. Bony defects in the oral cavity can vary significantly, ranging from smaller intrabony lesions resulting from periodontal or peri-implant diseases to large osseous defects that extend through the jaws as a result of trauma, tumor resection, or congenital defects. The disparity in size and location of these alveolar defects is compounded further by patient-specific and environmental factors that contribute to the challenges in periodontal regeneration, peri-implant tissue regeneration, and alveolar ridge reconstruction. Efforts have been made over the last few decades to produce reliable and predictable methods to stimulate bone regeneration in alveolar bone defects. Tissue engineering/regenerative medicine provide new avenues to enhance tissue regeneration by introducing bioactive models or constructing patient-specific substitutes. This review presents an overview of therapies (e.g., protein, gene, and cell based) and biomaterials (e.g., resorbable, nonresorbable, and 3-dimensionally printed) used for alveolar bone engineering around teeth and implants and for implant site development, with emphasis on most recent findings and future directions.

183 citations

Journal ArticleDOI
TL;DR: This review aims to be a comprehensive and general summary of the different isoxazolidine syntheses, their use as starting building blocks for the preparation of natural compounds, and their main biological activities.
Abstract: The isoxazolidine ring represents one of the privileged structures in medicinal chemistry, and there have been an increasing number of studies on isoxazolidine and isoxazolidine-containing compounds. Optimization of the 1,3-dipolar cycloaddition (1,3-DC), original methods including electrophilic or palladium-mediated cyclization of unsaturated hydroxylamine, has been developed to obtain isoxazolidines. Novel reactions involving the isoxazolidine ring have been highlighted to accomplish total synthesis or to obtain bioactive compounds, one of the most significant examples being probably the thermic ring contraction applied to the total synthesis of (±)-Gelsemoxonine. The unique isoxazolidine scaffold also exhibits an impressive potential as a mimic of nucleosides, carbohydrates, PNA, amino acids, and steroid analogs. This review aims to be a comprehensive and general summary of the different isoxazolidine syntheses, their use as starting building blocks for the preparation of natural compounds, and their m...

176 citations