Publications by authors named "Michael A Kerr"

68 Publications

Annulation of Oxime-Ether Tethered Donor-Acceptor Cyclopropanes.

Chemistry 2020 Jan 3;26(1):171-175. Epub 2019 Dec 3.

Department of Chemistry, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.

Novel oxime-ether tethered cyclopropanes, when exposed to Yb(OTf) and heat, annulate to generate hydropyrrolo-oxazines products that can be taken to their respective pyrrolidines via hydrogenative N-O bond cleavage. The hydropyrrolo-oxazines are generated in a diastereoselective manner isolating the cis or trans product based on the temperature of the reaction. 20 examples of selective cis and trans hydropyrrolo-oxazines were generated in high yields by temperature control.
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http://dx.doi.org/10.1002/chem.201904521DOI Listing
January 2020

Tandem Cyclopropanation/Vinylogous Cloke-Wilson Rearrangement for the Synthesis of Heterocyclic Scaffolds.

Org Lett 2018 12 15;20(23):7624-7627. Epub 2018 Nov 15.

Department of Chemistry , The University of Western Ontario , London , Ontario , Canada N6A 5B7.

Cyclopropanation of 1,3-dienes with ethyl 2-formyldiazoacetate under rhodium catalysis results in either a tandem cyclopropanation/Cloke-Wilson rearrangement or a vinylogous variant, depending on the diene used. These adducts may be subjected to an oxygen to nitrogen substitution with various amines under palladium catalysis. The substrate scope and mechanistic reasoning is presented.
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http://dx.doi.org/10.1021/acs.orglett.8b03361DOI Listing
December 2018

Total Synthesis of Isodihydrokoumine, (19 Z)-Taberpsychine, and (4 R)-Isodihydroukoumine N-Oxide.

J Am Chem Soc 2018 07 28;140(27):8415-8419. Epub 2018 Jun 28.

Department of Chemistry , University of Western Ontario , 1151 Richmond Street , London , ON N6A 3K7 , Canada.

We report the total synthesis of the natural products isodihydrokoumine and (19 Z)-taberpsychine in 11 steps each and (4 R)-isodihydrokoumine N-oxide in 12 steps from commercially available starting materials. The key reactions include an intramolecular [3 + 2] nitrone cycloaddition and Lewis acid mediated cyclizations of a common intermediate to provide the core structures of either taberpsychine or isodihydrokoumine.
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http://dx.doi.org/10.1021/jacs.8b05095DOI Listing
July 2018

Nucleophilic Opening of Donor-Acceptor Cyclopropanes with Indoles via Hydrogen Bond Activation with 1,1,1,3,3,3-Hexafluoroisopropanol.

J Org Chem 2018 06 23;83(11):6235-6242. Epub 2018 May 23.

Department of Chemistry , The University of Western Ontario , London , Ontario N6A 5B7 , Canada.

The treatment of donor-acceptor cyclopropanes with the a strong hydrogen bond donor, HFIP, activated the cyclopropanes (via presumed hydrogen bonding) toward homo-Michael additions with indoles as the nucleophiles. This reaction proceeded without the need for high pressure or catalysis.
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http://dx.doi.org/10.1021/acs.joc.8b00894DOI Listing
June 2018

Annulation Reactions of Donor-Acceptor Cyclopropanes with (1-Azidovinyl)benzene and 3-Phenyl-2H-azirine.

Org Lett 2016 09 6;18(18):4738-41. Epub 2016 Sep 6.

Department of Chemistry, The University of Western Ontario , London, Ontario, Canada N6A 5B7.

Under the influence of heat and Lewis acid, donor/acceptor cyclopropanes underwent annulation reactions with (1-azidovinyl)benzene and 3-phenyl-2H-azirine to form an unusual azabicyclic scaffold with an imbedded aziridine. The mechanism of reaction is believed to proceed via a vinyl nitrene intermediate.
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http://dx.doi.org/10.1021/acs.orglett.6b02409DOI Listing
September 2016

Cascade Reaction of Donor-Acceptor Cyclopropanes: Mechanistic Studies on Cycloadditions with Nitrosoarenes and cis-Diazenes.

Org Lett 2016 06 7;18(12):2922-5. Epub 2016 Jun 7.

Department of Chemistry, The University of Western Ontario , 1151 Richmond Street, London, ON N6A 5B7, Canada.

Tandem ring opening, elimination, and cycloaddition of donor-acceptor cyclopropanes were observed in Yb(OTf)3-catalyzed cycloaddition with nitrosoarenes. The reaction results in formation of tetrahydro-1,2-oxazine instead of the normal cycloadduct isoxazolidine via in situ nitrone formation. A similar cascade sequence was observed with cis-diazines. Mechanistic studies on this unique transformation offer an entirely new approach for reaction design with donor-acceptor cyclopropanes.
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http://dx.doi.org/10.1021/acs.orglett.6b01269DOI Listing
June 2016

Radical Cyclizations for the Synthesis of Pyrroloindoles: Progress toward the Flinderoles.

Org Lett 2016 05 15;18(9):2142-5. Epub 2016 Apr 15.

Department of Chemistry, The University of Western Ontario , London, Ontario, Canada , N6A 5B7.

Under the influence of Lewis acid catalysis, donor/acceptor cyclopropanes underwent nucleophilic ring opening by indolines. The resulting N-alkyl indolines bearing a pendant malonyl moiety oxidatively cyclized to 1,2-pyrroloindoles. This method was showcased by the preparation of the skeletal structure of the flinderoles.
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http://dx.doi.org/10.1021/acs.orglett.6b00768DOI Listing
May 2016

Untargeted plasma and tissue metabolomics in rats with chronic kidney disease given AST-120.

Sci Rep 2016 Mar 2;6:22526. Epub 2016 Mar 2.

Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.

Chronic kidney disease (CKD) results in the accumulation of metabolic waste products that are normally cleared by the kidney, known as uremia. Many of these waste products are from bacteria metabolites in the gut. Accumulation of uremic toxins in plasma and tissue, as well as the gut-plasma-tissue metabolic axis are important for understanding pathophysiological mechanisms of comorbidities in CKD. In this study, an untargeted metabolomics approach was used to determine uremic toxin accumulation in plasma, liver, heart and kidney tissue in rats with adenine-induced CKD. Rats with CKD were also given AST-120, a spherical carbon adsorbent, to assess metabolic changes in plasma and tissues with the removal of gut-derived uremic toxins. AST-120 decreased >55% of metabolites that were increased in plasma, liver and heart tissue of rats with CKD. CKD was primarily defined by 8 gut-derived uremic toxins, which were significantly increased in plasma and all tissues. These metabolites were derived from aromatic amino acids and soy protein including: indoxyl sulfate, p-cresyl sulfate, hippuric acid, phenyl sulfate, pyrocatechol sulfate, 4-ethylphenyl sulfate, p-cresol glucuronide and equol 7-glucuronide. Our results highlight the importance of diet and gut-derived metabolites in the accumulation of uremic toxins and define the gut-plasma-tissue metabolic axis in CKD.
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http://dx.doi.org/10.1038/srep22526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4773761PMC
March 2016

Carbocycles from donor-acceptor cyclopropanes.

Org Biomol Chem 2015 Jan;13(3):655-71

The University of Western Ontario, Department of Chemistry, London, Ontario, Canada N6A 5B7.

This review summarizes research directed towards the formation of carbocyclic adducts from donor-acceptor cyclopropanes. The focus of the review is on annulation and cycloaddition reactions (both inter- and intramolecularly) mediated by Lewis or protic acid, bases, or thermal conditions. Rearrangements resulting in carbocycles and those reactions mediated by transition metal catalysis have been excluded.
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http://dx.doi.org/10.1039/c4ob02117gDOI Listing
January 2015

Scandium triflate-catalyzed nucleophilic additions to indolylmethyl Meldrum's acid derivatives via a gramine-type fragmentation: synthesis of substituted indolemethanes.

J Org Chem 2013 Oct 8;78(20):10534-40. Epub 2013 Oct 8.

Department of Chemistry, The University of Western Ontario , London, Ontario, Canada N6A 5B7.

Treatment of indolylmethyl Meldrum's acids with catalytic scandium triflate and a variety of nucleophiles results in the nucleophilic displacement of the Meldrum's acid moiety via a gramine-type fragmentation. The reaction is useful for the generation of heterocyclic compounds of significant molecular complexity.
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http://dx.doi.org/10.1021/jo4017524DOI Listing
October 2013

γ-Substituted butanolides from cyclopropane hemimalonates: an expedient synthesis of natural (R)-dodecan-4-olide.

Org Lett 2013 Sep 5;15(18):4838-41. Epub 2013 Sep 5.

Department of Chemistry, The University of Western Ontario , London, Ontario, Canada N6A 5B7.

Exploration into the reactivity of donor-acceptor cyclopropane hemimalonates has led to the facile synthesis of γ-substituted butanolides. Under microwave irradiation, cyclopropane hemimalonates undergo rapid conversion to butanolides in the presence of inorganic salts with an unprecedented retention of stereochemistry. This unique process has been applied to the total synthesis of the naturally occurring (R)-dodecan-4-olide.
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http://dx.doi.org/10.1021/ol402252uDOI Listing
September 2013

Multicomponent synthesis of pyrroles from cyclopropanes: a one-pot palladium(0)-catalyzed dehydrocarbonylation/dehydration.

Angew Chem Int Ed Engl 2012 Oct 4;51(44):11088-91. Epub 2012 Oct 4.

Department of Chemistry, The University of Western Ontario, London, ON, N6A 5B7, Canada.

Ring the changes: The cycloaddition of nitrones with 1-carboallyloxy-1-carbomethoxycyclopropanes yields tetrahydro-1,2-oxazines, which in turn undergo a Tsuji dehydrocarbonylation to give dihydro-1,2-oxazines (see scheme; dba = dibenzylideneacetone). Addition of base to this reaction mixture results in clean conversion to pyrroles. The result is a flexible three-component strategy for the synthesis of tetrasubstituted pyrroles.
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http://dx.doi.org/10.1002/anie.201206177DOI Listing
October 2012

Tandem ring-opening decarboxylation of cyclopropane hemimalonates with sodium azide: a short route to γ-aminobutyric acid esters.

J Org Chem 2012 Aug 16;77(15):6634-7. Epub 2012 Jul 16.

Department of Chemistry, Western University, London, Ontario, Canada N6A 5B7.

Cyclopropane hemimalonates, when treated with sodium azide, undergo a tandem ring-opening decarboxylation to produce γ-azidobutyric acids in good yields. These adducts were hydrogenated to form γ-aminobutyric acid (GABA) methyl esters.
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http://dx.doi.org/10.1021/jo3010606DOI Listing
August 2012

Nucleophilic ring opening of cyclopropane hemimalonates using internal Brønsted acid activation.

Org Lett 2011 Aug 18;13(16):4180-3. Epub 2011 Jul 18.

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

The reaction of cyclopropanes, geminally disubstituted with one carboalkoxy and one carbohydroxy group, undergoes ring-opening reactions with indole nucleophiles under catalyst-free, hyperbaric (13 kbar) conditions. An internal hydrogen bond is postulated as the mode of activation obviating the need for the Lewis acid catalyst normally used for such donor-acceptor cyclopropane chemistry. These conditions avoid decarboxylation and yield useful adducts with the carboxylic acid group intact for further elaboration.
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http://dx.doi.org/10.1021/ol201486xDOI Listing
August 2011

Tandem cyclopropane ring-opening/Conia-ene reactions of 2-alkynyl indoles: a [3 + 3] annulative route to tetrahydrocarbazoles.

Org Lett 2011 Jan 16;13(2):220-3. Epub 2010 Dec 16.

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

A Zn(NTf(2))(2) catalyzed tandem reaction consisting of a nucelophilic ring opening of 1,1-cyclopropanediesters by 2-alkynyl indoles followed by a Conia-ene ring closure results in the efficient one-step synthesis of tetrahydrocarbazoles. The adducts may be further elaborated to carbazoles.
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http://dx.doi.org/10.1021/ol102627eDOI Listing
January 2011

Direct functionalization of indoles: copper-catalyzed malonyl carbenoid insertions.

Org Lett 2010 Nov;12(21):4956-9

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

Indoles, when treated with dimethyl diazomalonate under catalysis by Cu(acac)(2), undergo C-H insertion reactions regioselectively depending on the substitution pattern on the indole moiety. Indoles where the 3-position is substituted give high yields of the C2-H insertion product. Microwave conditions are also disclosed which show comparable yields with reduced reaction times.
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http://dx.doi.org/10.1021/ol1020948DOI Listing
November 2010

Total synthesis of (+)-isatisine A.

J Org Chem 2010 Oct;75(20):6830-41

Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 5B7.

The asymmetric total synthesis of (+)-isatisine A has been accomplished commencing with a Lewis acid-catalyzed cyclization of homochiral (S)-vinylcyclopropane diester and N-tosylindole-2-carboxaldehyde to construct the tetrahydrofuran ring. A palladium-catalyzed oxidative decarboxylation was utilized to obtain the dihydrofuran required for the subsequent dihydroxylation reaction to install the diol present on the tetrahydrofuran ring. The total synthesis was completed by an indole oxidation and electrophilic aromatic substitution sequence to construct isatisine A acetonide, which was then carried forward to the antipode of the natural product. The absolute configuration of the natural enantiomer (-)-isatisine A was determined to be C2(S), C9(R), C10(S), C12(R), and C13(R).
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http://dx.doi.org/10.1021/jo101209yDOI Listing
October 2010

Total synthesis of (+)-isatisine A.

Angew Chem Int Ed Engl 2010 Feb;49(6):1133-5

Department of Chemistry, The University of Western Ontario, London, ON, N6 A 5B7, Canada.

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http://dx.doi.org/10.1002/anie.200906632DOI Listing
February 2010

Synthesis of tetrahydropyrans from propargyl alcohols and 1,1-cyclopropanediesters: a one-pot ring-opening/Conia-ene protocol.

J Org Chem 2009 Nov;74(21):8414-6

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

Lewis acid catalyzed ring opening of 1,1-cyclopropanediesters by the hydroxyl group of a propargyl alcohol sets up a subsequent Conia-ene cyclization to afford substituted tetrahydropyrans in a one-pot, high-yielding procedure.
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http://dx.doi.org/10.1021/jo9019122DOI Listing
November 2009

Heterocycles from cyclopropanes: applications in natural product synthesis.

Chem Soc Rev 2009 Nov 10;38(11):3051-60. Epub 2009 Jul 10.

University of Western Ontario, Department of Chemistry, London, ON, N6A 5B7, Canada.

The construction of heterocyclic compounds from activated cyclopropane derivatives offers an alternative strategy for the preparation of molecules that may be of interest from a structural or biological standpoint. Several newly developed methods provide access to densely functionalized heterocycles in a manner that can be considered useful for both diversity- and target-oriented synthetic approaches. This tutorial review focuses on the latter, describing recent developments and applications of cyclopropane ring-expansion reactions in natural product synthesis.
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http://dx.doi.org/10.1039/b901245cDOI Listing
November 2009

Stereodivergent synthesis of fused bicyclopyrazolidines: access to pyrazolines and pyrrolidines.

Org Lett 2009 Oct;11(19):4354-7

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

The reaction of hydrazinoethyl 1,1-cyclopropanediesters with aldehydes in the presence of catalytic Yb(OTf)(3) allows access to structurally complex fused bicyclo pyrazolidines. Either 2,5-cis or 2,5-trans adducts can be obtained in good to excellent yields in most cases by simply controlling the order of addition of the catalyst and aldehyde.
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http://dx.doi.org/10.1021/ol901744eDOI Listing
October 2009

Zn(II)-Catalyzed synthesis of piperidines from propargyl amines and cyclopropanes.

Org Lett 2009 Aug;11(16):3770-2

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

The reaction of benzyl-protected propargyl amines and 1,1-cyclopropane diesters in the presence of catalytic Zn(NTf(2))(2) allows access to highly functionalized piperidines in excellent yields. The process proceeds via a tandem cyclopropane ring-opening/Conia-ene cyclization.
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http://dx.doi.org/10.1021/ol901435kDOI Listing
August 2009

Domino synthesis of bridged bicyclic tetrahydro-1,2-oxazines: access to stereodefined 4-aminocyclohexanols.

Org Lett 2009 Aug;11(16):3694-7

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

The intramolecular variant of the homo-[3 + 2]-dipolar cycloaddition of nitrones (generated in situ from an aldehyde and a hydroxylamine) with donor-acceptor cyclopropanes allows for the efficient synthesis of bridged tetrahydro-1,2-oxazines. This domino sequence produces adducts amenable to reductive N-O bond cleavage producing cis-1,4-aminocyclohexanols in excellent yields.
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http://dx.doi.org/10.1021/ol901454yDOI Listing
August 2009

Synthesis of cyclohexanes via [3 + 3] hexannulation of cyclopropanes and 2-chloromethyl allylsilanes.

Org Lett 2009 May;11(10):2081-4

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada, N6A 5B7.

Lewis acid-assisted ring-opening/allylation of 1,1-cyclopropane diesters, followed by base-mediated ring closure, generates functionalized exo-methylenecyclohexanes in good yield. This two-step procedure is highlighted by expedient preparation of a pyrido[1,2-a]indole skeleton common to the chippiine class of Iboga indole alkaloids.
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http://dx.doi.org/10.1021/ol900457zDOI Listing
May 2009

Functional and structural characterisation of human colostrum free secretory component.

Mol Immunol 2009 Apr 23;46(7):1534-41. Epub 2009 Feb 23.

Department of Pathology, College of Medicine and King Khalid University Hospital, King Saud University, P.O. Box 2925, Riyadh 11461, Saudi Arabia.

Secretory component (SC) in association with polymeric IgA (pIgA) forms secretory IgA (SIgA), the major antibody active at mucosal surfaces. SC also exists in a free form in secretions, with innate neutralizing properties against important pathogens. IgA-bound SC and free secretory component (FSC) are both produced by proteolytic cleavage of the polymeric Ig receptor whose function is to transport IgA and IgM across mucosal epithelia. Although the proteases have not been characterised and the site(s) of cleavage of the polymeric Ig receptor has been debated, it has been assumed that bound and free SC are produced by cleavage at the same site. Here we show by SDS-PAGE analyses that FSC is slightly smaller than SIgA1- or SIgA2-bound SC when purified simultaneously. The FSC preparation was functionally active, shown by binding to dimeric and polymeric IgA, and by its ability to trigger a respiratory burst by binding to 'SC receptors' on eosinophils. We also show that FSC from different human secretions have different molecular sizes. The solution structure of FSC from colostrum was studied by analytical ultracentrifugation and X-ray scattering. The sedimentation coefficient of 4.25S is close to that for recombinant FSC. The X-ray scattering curve showed that FSC adopts a compact structure in solution which corresponds well to the J-shaped domain arrangement determined previously for recombinant FSC which terminates at residue Arg585. The smaller sizes of the FSC forms are attributable to variable cleavages of the C-terminal linker region, and may result from the absence of dimeric IgA. The FSC modelling accounts for the lack of effect of the C-terminal linker on the known functions of FSC.
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http://dx.doi.org/10.1016/j.molimm.2008.12.022DOI Listing
April 2009

Total synthesis of FR901483.

Org Lett 2009 Feb;11(3):777-9

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.

The architecturally sophisticated skeleton of the immunosuppressive alkaloid FR901483 was assembled via a process relying on the reaction of an in situ generated imine with a suitably disposed donor-acceptor cyclopropane. A short sequence of functional group transformations provided the natural product in an efficient manner.
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http://dx.doi.org/10.1021/ol802870cDOI Listing
February 2009

The nonplanar secretory IgA2 and near planar secretory IgA1 solution structures rationalize their different mucosal immune responses.

J Biol Chem 2009 Feb 23;284(8):5077-87. Epub 2008 Dec 23.

Institute of Structural and Molecular Biology, Division of Biosciences, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom.

Secretory IgA (SIgA) is the most prevalent human antibody and is central to mucosal immunity. It exists as two subclasses, SIgA1 and SIgA2, where SIgA2 has a shorter hinge joining the Fab and Fc regions. Both forms of SIgA are predominantly dimeric and contain an additional protein called the secretory component (SC) that is attached during the secretory process and is believed to protect SIgA in harsh mucosal conditions. Here we locate the five SC domains relative to dimeric IgA2 within SIgA2 using constrained scattering modeling. The x-ray and sedimentation parameters showed that SIgA2 has an extended solution structure. The constrained modeling of SIgA2 was initiated using two IgA2 monomers that were positioned according to our best fit solution structure for dimeric IgA1. SC was best located along the convex edge of the Fc-Fc region. The best fit models showed that SIgA2 is significantly nonplanar in its structure, in distinction to our previous near planar SIgA1 structure. Both the shorter IgA2 hinges and the presence of SC appear to displace the four Fab regions out of the Fc plane in SIgA2. This may explain the noncovalent binding of SC in some SIgA2 molecules. This nonplanar structure is predicted to result in specific immune properties for SIgA2 and SIgA1. It may explain differences observed between the SIgA1 and SIgA2 subclasses in terms of their interactions with antigens, susceptibility to proteases, effects on receptors, and distribution in different tissues. The different structures account for the prevalence of both forms in mucosal secretions.
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http://dx.doi.org/10.1074/jbc.M807529200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2643523PMC
February 2009

Serologic diagnosis of allergic bronchopulmonary aspergillosis in patients with cystic fibrosis through the detection of immunoglobulin G to Aspergillus fumigatus.

Diagn Microbiol Infect Dis 2008 Nov;62(3):287-91

Department of Microbiology, Leeds Teaching Hospitals Trust, Leeds, UK.

Allergic bronchopulmonary aspergillosis (ABPA) is seen in approximately 10% of patients with cystic fibrosis (CF) and can be difficult to diagnose. Consensus criteria require the presence of multiple elevated immunologic markers such as total immunoglobulin E (IgE), Aspergillus IgE and Aspergillus IgG, or precipitins for a robust diagnosis. There is some degree of standardization of total IgE and Aspergillus IgE levels, but there is no standardization in the measurement of IgG antibodies or precipitins to Aspergillus. The interpretation of results may, therefore, be confusing. Eighty-seven patients with CF were categorized as having ABPA or as controls, using the consensus criteria and an in-house enzyme immunoassay to measure IgG levels to Aspergillus. All sera from patients were then analyzed by commercial fluorescent immunoassay (FEIA) for the quantitative detection of anti-Aspergillus IgG. FEIA results were analyzed against the consensus conference minimum diagnostic criteria to ascertain a cutoff point, which could predict a diagnosis of ABPA in CF. Eighty patients with CF and with no or incomplete evidence of ABPA had a mean FEIA score of 51.1 mg/L, whereas 7 CF patients with ABPA had a mean FEIA score of 132.5 mg/L. Using receiver operator characteristic curve analysis of the ImmunoCAP (Phadia) IgG score on ABPA versus all other patients gave an area under the curve of 0.933 (estimated SE, 0.027). This analysis provisionally suggested that a score of 90 mg/L may be used as a cutoff point, which would give a sensitivity of 91% and specificity of 88.0% for the diagnosis of ABPA, though this requires further validation. This quantitative approach to Aspergillus IgG measurement in patients with CF along with the results of other tests will hopefully provide a more accurate approach to the diagnosis of ABPA.
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http://dx.doi.org/10.1016/j.diagmicrobio.2008.06.018DOI Listing
November 2008

Total synthesis of (-)-allosecurinine.

Angew Chem Int Ed Engl 2008 ;47(41):7945-8

Department of Chemistry, The University of Western Ontario, London, ON, Canada.

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http://dx.doi.org/10.1002/anie.200803257DOI Listing
November 2008

Expedient synthesis of pyrrolo[1,2-a]indoles: preparation of the core of yuremamine.

Org Lett 2008 Aug 11;10(16):3497-500. Epub 2008 Jul 11.

Department of Chemistry, The University of Western Ontario, London, Ontario, Canada.

Pyrrolo[1,2- a]indoles are conveniently prepared from tetrahydro-1,2-oxazines, which in turn are generated through the reaction of nitrones with 1,1-cyclopropanediesters. The synthetic route proves to be highly diastereoselective and provides access to the core of the recently discovered pyrrolo[1,2- a]indole natural product yuremamine.
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http://dx.doi.org/10.1021/ol8012777DOI Listing
August 2008