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Showing 1 to 20 of 90 for “"stereospecific"”.
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Stereospecific Syntheses from Podocarpic Acid
The triterpene precursor, 12-methoxypodocarpa-8,11,13-trien-3-one (46)*, has been prepared via the 3a-alcohol (48) formed by opening of the 3a,4a-epoxide (13) with lithium diethylamide. The total synthesis of the methyl ether of the natural product, (+)-hinokione, has been achieved by a similar …
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Studies on the Stereospecific Synthesis of Trisubstituted Olefins
Made available in DSpace on 2014-12-10T23:01:46Z (GMT). No. of bitstreams: 1 7412113.pdf: 2628191 bytes, checksum: dda504b7a7be7e1562b8692daed36af3 (MD5) Previous issue date: 1973
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Stereospecific Csp3 cross-coupling for modular polyketide synthesis
… cross-coupling reactions. Here, I show that stereospecific palladium-catalyzed cross-coupling reactions of secondary alkyl organoboron nucleophiles can be leveraged to access the alpha-methyl-beta-hydroxyl motif that is ubiquitous amongst polyketide and other natural products. To achieve this …
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Stereospecific total synthesis of beta-lactam antibiotics from peptide precursors.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1978
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Part One: Stereospecific Synthesis of Trisubstituted Olefins. Part Two: Cephalotaxus Alkaloid Esters
Made available in DSpace on 2014-12-13T20:09:48Z (GMT). No. of bitstreams: 1 7606999.pdf: 4588533 bytes, checksum: b276a6c9ec0d3ea23da6f850f28f72e2 (MD5) Previous issue date: 1975
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STEREOSPECIFIC SUZUKI-MIYAURA CROSS-COUPLING OF CHIRAL BENZYLIC BORONIC ESTERS AND VINYL BROMIDES
… 2009, our group reported the first example of a stereospecific coupling between chiral secondary boronic esters and aryl iodides. In this thesis, we report our investigations towards expanding the scope of our established Csp2-Csp3 coupling reaction with chiral boronic esters. By employing vinyl …
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Studies on stereospecific diketopiperazine oxidation and applications to the synthesis of complex epidithiodiketopiperazines
… of complex ETPs are examined. II. Studies on Stereospecific Diketopiperazine C–H Hydroxylation Mechanistic investigation of the permanganate-mediated hydroxylation reaction of 2,5-diketopiperazines (DKPs) is discussed. The course of the hydroxylation reaction with three permanganate oxidants …
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The Modified Stereospecific Stille Reaction: Palladium-Catalyzed Cross-Coupling Reactions Involving Secondary and Tertiary Alkyl Carbastannatranes
… scope of reactants, and even proceed with high stereospecificity. The development of a general system that enables a broad scope of reactants to be employed in reactions with high sterespecificity would be transformative in the field of organic synthesis and drug development. Herein, in the …
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Halo enol lactone and protio enol lactone inhibitors of alpha-chymotrypsin: Mechanism and stereospecific behavior of inhibition
A kinetic study of inactivation of $\alpha$-chymotrypsin by enol lactones was performed. Halo enol lactones, 3-(1-naphthyl)-6(E)-(iodomethylene)tetrahydro-2-pyranone ($\alpha$Np6I) and 3-phenyl-6(E)-(bromomethylene)tetrahydro-2-pyranone ($\alpha$Ph6Br), showed burst kinetics in the inactivation of …
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A Stereospecific Pd-Catalyzed Suzuki Cross-Coupling Reaction and a Statistical Study of the Ligand's Role in Stereoselection
<p>The development of palladium-catalyzed carbon-carbon cross-coupling reactions has profoundly influenced the manner through which we approach the synthesis of complex organic molecules. Among established cross-coupling reactions, which include Kumada, Negishi, and Stille reactions, the Suzuki …
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Stereospecific alkynylation at the more hindered carbon of trisubstituted epoxides and concise syntheses of bis-THF acetogenins and analogues
… in 75-80% isolated yield. The reaction is stereospecific with inversion at the substitution center. This work constitutes the first general method for the addition of a carbon nucleophile at the more congested site of a trisubstituted epoxide. The less efficient alkynyl alane reagents for …
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The interactions of Propafenone and its enantiomers with the major human forms of cytochrome P450 in terms of inhibition and metabolic rates
… CYP1A2, CYP3A4 and CYP2C19) to determine any stereospecific differences which may exist. This was conducted by measuring the in vitro metabolism of propafenone (racemate and enatiomers) and by developing CYP inhibition screens which could prove to be useful in providing information of …
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Total synthesis and study of myrmicarin alkaloids
… in this convergent approach include a stereospecific palladium-catalyzed N-vinylation of a pyrrole with a vinyl triflate, a copper-catalyzed enantioselective conjugate reduction of a P-pyrrolyl enoate, and a regioselective Friedel-Crafts reaction. The synthesis of optically active and …
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ROLE OF 12/15 LIPOXYGENASE EXPRESSION IN LIPID METABOLISM, ATHEROSCLEROSIS AND INSULIN RESISTANCE
… of a family of enzymes that can catalyze the stereospecific incorporation of oxygen into polyunsaturated fatty acids (PUFAs), forming a series of bioactive lipid mediators. Though lipid mediators produced by 12/15LO have the potential to affect lipid metabolism and atherosclerosis, the role of …
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Stereochemistry of the Allene-Forming Cycloelimination of 4-Diazo-3,5-Diethyl-3,5-Dimethyl-1-Pyrazoline
… (2). To achieve this goal, a stereospecific synthesis of 1a which would permit its optical resolution was devised. Cyclization of tosylhydrazine and 4,5-epoxy-5-methyl-3-heptanone (3) provides a mixture of diastereomeric pyrazolols 4a and 5a, which upon oxidation to the
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