A5025135705- Synthetic Organic Chemistry Methods
- Oxidative Organic Chemistry Reactions
- Synthesis and Catalytic Reactions
- Chemical synthesis and alkaloids
- Marine Sponges and Natural Products
- Carbohydrate Chemistry and Synthesis
- Cyclopropane Reaction Mechanisms
- Asymmetric Synthesis and Catalysis
- Traditional and Medicinal Uses of Annonaceae
- Alkaloids: synthesis and pharmacology
- Catalytic C–H Functionalization Methods
- Advanced Synthetic Organic Chemistry
- Chemical Reactions and Mechanisms
- Chemical Synthesis and Analysis
- Quinazolinone synthesis and applications
- Synthesis and Biological Evaluation
- Respiratory viral infections research
- Synthesis of Tetrazole Derivatives
- Virus-based gene therapy research
- Marine Toxins and Detection Methods
- Catalytic Alkyne Reactions
- Enzyme Catalysis and Immobilization
- Histone Deacetylase Inhibitors Research
- Influenza Virus Research Studies
- Vanadium and Halogenation Chemistry
University of Illinois Chicago
2009-2024
University of Chicago
2001-2014
Oregon State University
1999-2005
The development of a versatile method for the preparation five- to eight-membered hydroxy lactams that involves iodine(III)-mediated oxamidation unsaturated O-alkyl hydroxamates is described. This transformation, which believed proceed through intermediacy singlet nitrenium and bicyclic N-acyl-N-alkoxyaziridinium ions, both stereospecific highly regioselective in most 22 cases examined.
[reaction: see text] A convenient method for the preparation of 2,5-dihydrofurans by using chemistry alkynyl(phenyl)iodonium salts is reported. Treatment 3-alkoxy-1-alkynyl(phenyl)iodonium triflates with sodium benzenesulfinate generates an alkylidenecarbene, which undergoes [1,5]-C-H insertion to form 2-substituted 4-benzenesulfonyl-2,5-dihydrofurans in reasonable yield. These cyclic vinyl sulfones are functionalized such a way as make them useful starting materials lignans. The application...
Herein, we report the development of an antifiloviral screening system, based on a pseudotyping strategy, and its application in discovery novel group small molecules that selectively inhibit Ebola Marburg glycoprotein (GP)-mediated infection human cells. Using Zaire GP-pseudotyped HIV particles bearing luciferase reporter gene 293T cells, library 237 was screened for inhibition GP-mediated viral entry. From this assay, lead compound 8a identified as selective inhibitor filoviral entry with...
[structure: see text]. A formal synthesis of the muscarinic M(1) receptor antagonist (-)-TAN1251A (7) from L-tyrosine is described. Central to this venture has been construction 1-azaspiro[4.5]decane skeleton present in natural product by an N-methoxy-N-acylnitrenium ion-induced spirocyclization. The dienone generated transformation, 10, was converted via tricycle 9, intermediate Kawahara's recent racemic 7.
Although 1,4-cyclohexadienes 2, obtained through the Birch reduction of arenes 1, have found widespread use as masked β-oxo carbonyl synthons 3, possibility that 2,5-cyclohexadienones 5 might also be employed to same end has been overlooked despite their ready availability. As part our ongoing investigation synthetic chemistry nitrenium ions, we developed a novel and efficient strategy for stereoselective preparation di- trisubstituted azetidinone, pyrrolidinone, piperidinone derivatives,...
The asymmetric total synthesis of the α-glucosidase inhibitor (+)-castanospermine is reported. central theme in our approach to this polyhydroxylated alkaloid simultaneous generation piperidine ring and C-1/8a erythro stereodiad through diastereoselective, oxamidation an unsaturated O-alkyl hydroxamate. This process believed proceed sequentially via singlet acylnitrenium aziridinium ion intermediates.
A stereoselective synthesis of agelastatin A, a potent cytotoxin and inhibitor osteopontin (OPN)-mediated neoplastic transformations, has been accomplished in 14 steps (12 operations) with an approximate overall yield 8%. Notable features this route include the direct manner which pyrroloketopiperazine A-ring target is generated efficient employment trichloroacetamide, introduced through Overman rearrangement, as protecting group, pendant nucleophile, latent urea.
The total synthesis of (−)-swainsonine from 2,3-O-isopropylidene-d-erythrose in 12 steps and an overall yield 28% is reported. pivotal transformation our route to this indolizidine alkaloid the formation pyrrolidine ring C-8a/8 stereodiad through diastereoselective, bis-cyclofunctionalization γ,δ-unsaturated O-alkyl hydroxamate. This believed proceed via intramolecular capture N-acyl-N-alkoxyaziridinium ion generated by diastereoselective addition a singlet acylnitrenium pendant alkene.
The formal synthesis of (±)-desmethylamino FR901483 (2) is described. Construction the unique azatricyclic skeleton 2 was accomplished by a sequence which involved (i) preparation dienone 7 an N-methoxy-N-acylnitrenium ion-induced spirocyclization, (ii) formation 2-azabicyclo[3.3.1]nonane 5 6-(π-exo)-exo-trig radical cyclization 1,7-enyne 6, and (iii) installation C-5 p-methoxybenzyl side chain Lewis acid-mediated alkylation silyl enol ether 18.
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTTotal Synthesis of the Marine Toxin Polycavernoside A via Selective Macrolactonization a Trihydroxy Carboxylic AcidJames D. White, Paul R. Blakemore, Cindy C. Browder, Jian Hong, Christopher M. Lincoln, Pavel A. Nagornyy, Lonnie Robarge, and Duncan J. WardropView Author Information Department Chemistry, Oregon State University Corvallis, 97331-4003 Cite this: Am. Chem. Soc. 2001, 123, 35, 8593–8595Publication Date (Web):August 10,...
Two approaches to the synthesis of aglycon 120 polycavernoside A (1) were developed, only one which was completed. The successful "second-generation" route assembled seco acids 102 and 106 via Nozaki−Hiyama−Kishi coupling aldehyde 70, prepared from methyl (S)-3-hydroxy-2-methylpropionate (72) (S)-pantolactone (73), with vinyl bromide 71. latter obtained a sequence commenced silyl ether 24 3-hydroxypropionaldehyde entailed cyclization (Z)-ζ-hydroxy-α,β-unsaturated ester 82. Regioselective...
The enantioselective total synthesis of the potent α-glucosidase inhibitors schulzeine A, B, and C a revision proposed C20′ configuration A are reported. central feature our convergent route to this family novel marine natural products is preparation common benzo[a]quinolizidine subunit through substrate-controlled, diastereoselective Pictet−Spengler cyclocondensation.
The diastereoselective total synthesis of the marine natural product (−)-dysibetaine is reported. key steps in this venture are i) a nitrenium ion spirocyclization, which serves to generate pyrrolidinone ring and quaternary stereocenter target, ii) use 2-methoxycyclohexa-2,5-dienone formed during cyclization as masked 2-amino-1,3-dicarbonyl synthon.
In the course of screening for new small-molecule modulators cell motility, we discovered that quinocarmycin (also known as quinocarcin) analog DX-52-1 is an inhibitor epithelial migration. While it has been assumed main target DNA, identified and confirmed radixin relevant molecular in cell. Radixin a member ezrin/radixin/moesin family membrane-actin cytoskeleton linker proteins also participate signal transduction pathways. binds specifically covalently to C-terminal region radixin, which...
A synthetic route to the neurotrophic agent (+)-lactacystin has been developed utilizing a base-promoted intramolecular alkylidenecarbene C-H insertion as key transformation.
The recent outbreak of H7N9 influenza in China is high concern to public health. H7 hemagglutinin (HA) plays a critical role entry and thus HA presents an attractive target for antivirals. Previous studies have suggested that the small molecule tert-butyl hydroquinone (TBHQ) inhibits H3 by binding stem loop stabilizing neutral pH conformation HA, thereby disrupting membrane fusion step. Based on amino acid sequence, structure immunogenicity, related Group 2 HA. In this work we show, using...
The embodiment of lactam rings within a wealth physiologically active natural products and pharmaceutical agents ensures that the development synthetic methods, which facilitate preparation these saturated N<i>-</i>heterocycles, is critical importance. Herein versatile method for synthesis 4 to 8-membered α-vinyl α-(2-silylvinyl) lactams involving iodine(III)-mediated oxidative cyclization unsaturated <i>O</i>-alkyl hydroxamates, encompass an allylsilane, reported. Importantly, outcome this...
A novel method for the stereospecific preparation of [4.5]spiroketal glycosides utilizing 1,5 C−H bond insertion alkylidenecarbenes is described. Treatment 2-oxopropyl β-pyranosides with lithium (trimethylsilyl)diazomethane in THF at −78 °C afforded 1,6-dioxaspiro[4,5]decenes B good yield. Submission corresponding α-glycosides C to same reagent gave isomeric products D moderate high
The development of a mild, base-free method for the generation alkylidenecarbenes is reported. Treatment 5-hydroxyalkyl-1H-tetrazoles with carbodiimides generates products arising from 1,2-rearrangement or [1,5]-C–H bond insertion putative alkylidenecarbene. Formation this divalent intermediate proposed to occur by way tetraazafulvene, which undergoes extrusion 2 mol dinitrogen. Details methodology, its application synthesis combretastatin A-4, and an improved route are described.