Publications by authors named "Kunal Keskar"

7 Publications

  • Page 1 of 1

The synthesis of densely functionalised α-acyloxy enaminals and enaminones via a novel homogeneous silver(i) catalysed rearrangement.

Chem Commun (Camb) 2019 Sep;55(73):10868-10871

Department of Chemistry & Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada.

A synthesis of densely functionalised α-acyloxy enaminals and enaminones via a novel homogeneous silver(i) catalyzed rearrangement of 1-acyloxy-3-azido ketones is reported. This silver catalyzed reaction involves an internal redox process comprised of four net transformations: loss of nitrogen, reductive cleavage of the azide, 1,2-acyl migration and oxidation of the acyloxy position to an aldehyde (enaminal) or ketone (enaminone). These mild reaction conditions have been applied to acyclic, cyclic, and chiral substrates yielding the rearranged enaminals or enaminones in up to 91% yield, all of which prove to be stable, isolatable products.
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http://dx.doi.org/10.1039/c9cc05614aDOI Listing
September 2019

Synthesis of the cyanobacterial metabolite nostodione A, structural studies and potent antiparasitic activity against Toxoplasma gondii.

Org Biomol Chem 2015 Oct;13(39):10015-24

Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, CanadaL8S 4M1.

A total synthesis of the cyanobacterial natural product nostodione A is reported involving a convergent, diversity-oriented route, enabling the assembly of a mini-library of structural analogues. The first single crystal X-ray structural determination on a member of this series is reported along with SAR studies identifying potent inhibitors of invasion and replication of the parasitic protozoan Toxoplasma gondii.
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http://dx.doi.org/10.1039/c5ob01506eDOI Listing
October 2015

Discovery of a new class of cinnamyl-triazole as potent and selective inhibitors of aromatase (cytochrome P450 19A1).

Bioorg Med Chem Lett 2014 Sep 7;24(18):4586-4589. Epub 2014 Aug 7.

Department of Obstetrics and Gynecology, McMaster University, 1280 Main Street West, Hamilton, Ont. L8S 4K1, Canada.

Synthesis of a novel class of natural product inspired cinnamyl-containing 1,4,5-triazole and the potent inhibition of human aromatase (CYP 450 19A1) by select members is described. Structure-activity data generated provides insights into the requirements for potency particularly the inclusion of an aryl bromide or chloride residue as a keto-bioisostere.
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http://dx.doi.org/10.1016/j.bmcl.2014.07.083DOI Listing
September 2014

High yielding synthesis of carboranes under mild reaction conditions using a homogeneous silver(I) catalyst: direct evidence of a bimetallic intermediate.

Angew Chem Int Ed Engl 2014 May 2;53(20):5156-60. Epub 2014 Apr 2.

Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St W., Hamilton, Ont., L8S 4M1 Canada; Department of Chemistry, Faculty of Science, Tanta University, 31527 Tanta (Egypt).

Methods used to prepare functionalized carboranes generally require heating to high temperatures, and thus limits the range of derivatives which can be prepared directly from alkynes. We show here that by using a homogeneous silver(I) catalyst it is now possible to prepare carboranes in good to excellent yield at temperatures below 40 °C, including at room temperature. The process is general and provides an important new synthetic strategy for the preparation of functionalized boron clusters.
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http://dx.doi.org/10.1002/anie.201311012DOI Listing
May 2014

Phthalide: a direct building-block towards P,O and P,N hemilabile ligands. Application in the palladium-catalysed Suzuki-Miyaura cross-coupling of aryl chlorides.

Org Biomol Chem 2013 Apr 5;11(15):2404-7. Epub 2013 Mar 5.

Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, CanadaL8S 4M1.

The direct synthesis of new hemilabile ligands from the economical, readily available lactone phthalide is described. Pd-complexes of one such ligand were found highly effective in general Suzuki-Miyaura cross-coupling reactions, including deactivated and hindered aryl chlorides.
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http://dx.doi.org/10.1039/c3ob40198gDOI Listing
April 2013

The first well-defined silver(I)-complex-catalyzed cycloaddition of azides onto terminal alkynes at room temperature.

Chemistry 2011 Dec 28;17(52):14727-30. Epub 2011 Nov 28.

Department of Chemistry and Chemical-Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4M1, Canada.

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http://dx.doi.org/10.1002/chem.201103244DOI Listing
December 2011

Isolation of flavonoids from the heartwood and resin of Prunus avium and some preliminary biological investigations.

Phytochemistry 2009 Dec;70(17-18):2040-6

Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1.

An investigation of the constituents in heartwood and resin of Prunus avium is reported. A mini-library of structurally diverse flavanones and flavones was screened for human cytochrome P450 1A1, 3A4 and 19 (aromatase) inhibition, and for antifungal activity against a panel of pathogenic fungi. The defensive role of these natural plant flavonoids as antifungal phytoalexins and phytoanticipins is discussed.
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http://dx.doi.org/10.1016/j.phytochem.2009.08.018DOI Listing
December 2009