Index Catalog // ScholarsArchive@OSU

Synthetic studies on marine natural products : I. Stereoselective synthesis of E,Z-1,3-Dienes by tandem nucleophilic addition to a dienylphosphonium salt followed by Wittig reaction. II. Synthesis of cyclopropyl oxylipins by a cation mediated carbocyclization

Creator:: Jensen, Mark S.
Resource Type:: Dissertation
Full Text:: . Stereoselective synthesis of E,Z-1,3-Dienes by tandem nucleophilic addition to a dienylphosphonium salt followed

Approaches to the total synthesis of verrucarol

Creator:: Hill, David E. (David Edwin) 1954-
Abstract:: Verrucarol is the sesquiterpene portion of a number of macrocyclic di- and triesters of potential medicinal importance. In this study, a novel approach to the synthesis of this fungal metabolite is presented. An A-B-C route was investigated in which C-3 and C-4 of the C-ring were emplaced using a [2+2]...
Resource Type:: Dissertation
Full Text:: ABSTRACT OF THE THESIS OF David E. Hill for the degree of Doctor of_Philosophy in Chemistry presented on

Studies towards the total synthesis of (-)-kendomycin

Creator:: Smits, Helmars
Abstract:: Studies towards the total synthesis of (−)-kendomycin (1), a bacterial metabolite with a unique molecular architecture and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediate 208, containing all of the carbon atoms of 1. A Dötz annulation between alkyne 122 and novel chromium carbenoid...
Resource Type:: Dissertation
Full Text:: testing as well as for the synthesis of analogs. O O OH O HO HO 13 16 18 20 1 4 4a 57 9

Absolute stereochemistry and total synthesis of botryococcene

Creator:: Reddy, Guvvala Nagabhushana
Abstract:: Studies were carried out to determine the absolute stereochemistry of botryococcene (1). The natural product was degraded to two sets of 'y- and 8- valerolactones. All enantiomeric variations of these lactones were synthesized in optically pure form starting from (S)- and (R)-methyloxiranes. 1H NMR correlation of natural and synthetic materials...
Resource Type:: Dissertation
Full Text:: -[(methoxymethypoxy]-3-E-hexenoate (126 and 127), and an organocopper coupling reaction. Methyl (2S)-3-hydroxy-2

Chiral synthesis of monic acid C

Creator:: Theramongkol, Parinya
Abstract:: Bromoalkoxylation of dihydropyran with bromine and 1-borneol, followed by dehydrobromination and epoxidation, afforded trans-2-1- bornyloxy-3,4-epoxytetrahydropyran as a major product. This was treated with sodium phenylselenide to give a 1:1 mixture of (2R,3R,4R)- 2-1-bornyloxy-3-hydroxy-4-phenylselenotetrahydropyran and its (2S,3S, 4S) diastereomer. Elimination of the selenoxide, derived from oxidation of the former with hydrogen...
Resource Type:: Dissertation
Full Text:: . Conformation of the Metal Ion Complex (M+ = e) of Lasalocid. 5 15 6 , R = H 7, R = OH 8 Ho 9 10 , R

Approaches to the synthesis of the macrolactone pyrrolizidine alkaloids (-)-integerrimine and (+)-usaramine

Creator:: Jayasinghe, Lalith Ratnasiri
Abstract:: A formal total synthesis of the macrolactone pyrolizidine alkaloid (-)-integerrimine (2), from R-(+)-citronellal (93) is described. Aldehyde 93 was converted to exo methylene derivative 94 which was reduced to allylic alcohol 95. The epoxides 96 and 98, obtained in a ratio of 3:1 respectively by Sharp less epoxidation of 95...
Resource Type:: Dissertation
Full Text:: of the primary alcohol of 102, followed by introduction of the E-ethylidene group, furnished 31

Synthetic studies on alkaloids : part I, an approach toward the synthesis of (̳+)-koumine : part II, an approach toward the synthesis of (̳+)-morphine

Creator:: Stappenbeck, Frank
Resource Type:: Dissertation
Full Text:: ) LiAIH4 C 02M e 4) AcCI, DMAP 5) PPTS, Et0H 81% 33 OTHP scheme 11 35 HO H N" EtO2C OAc Mg13r2 C

An approach toward the synthesis of euonyminol and cathedulin K- 19

Creator:: Shin, Hyunik
Abstract:: A synthetic approach toward the two major fragments of cathedulin K-19, euonyminol (4) and dimethyl cathate (69), was investigated. Synthesis of dimethyl cathate was accomplished in 3 steps starting from 73. Efforts directed towards the synthesis of euonyminol, a highly oxygenated dihydroagarofuran sesquiterpene, was advanced to a stage in which...
Resource Type:: Dissertation
Full Text:: 99 C 02Me 0,T19 OTBS (OR)n 98 Scheme 21 m-C P BA C H2Cl2 quant. E HO OH 0 98 C 02Me 0 OTBS

Studies toward the total synthesis of sanglifehrin A

Creator:: Suttisintong, Khomson
Abstract:: Studies toward synthesis of subunits of sanglifehrin A, an immunosuppressant featuring a highly substituted [5,5]-spirolactam moiety as well as a 22-membered macrocycle are described. The macrolactone contains a peptidic backbone characterized by an unusual [beta]-substituted (S)-piperazic acid and (S)-m-hydroxyphenylalanine units. These studies resulted in the synthesis of advanced intermediate 358...
Resource Type:: Dissertation
Full Text:: 2002. 2 O NH O HO OH OH OO N NH O NH O HN OH O O HO Sanglifehrin A (1) O NH

Approaches to the synthesis of methymycin

Creator:: Raghavan, Palaykotai Rajagopalan
Abstract:: Several approaches to the synthesis of methymycin were investigated. Segment A (39), containing functionality corresponding to C-9, 10, and 11 of methynolide was made in six steps from propionaldehyde in an overall yield of 37%. Oxidation of 34 with silver nitrate gave 35 which, upon hydroxylation with hydrogen peroxide, gave...
Resource Type:: Dissertation
Full Text:: V CHAININ (8) 0 e s',- HO 1! i. ).1 5 ,,,./ 10 0 4 2 ..`.3 411.''''Cr'j l'' OH OH ...a

Phenolic oxidative coupling : an approach to the synthesis of pretazettine

Creator:: Chong, Wesley Kwan Mung
Abstract:: Various hypervalent iodine compounds were evaluated as reagents for intramolecular phenolic oxidative coupling. It was found that phenyliodine(III) bis(trifluoroacetate) was effective for the coupling of the monophenolic substrate 13a to 14a under neutral conditions. Vanadium oxytrifluoride and hypervalent iodine compounds were compared as oxidants for the conversion of 32 to...
Resource Type:: Dissertation
Full Text:: ), a representative of " the crinine class of alkaloids. It is presumed that subsequent H3CO HO OH

Total synthesis of phorboxazole A

Creator:: Lee, Tae Hee
Abstract:: The total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, is described. Both a palladium(II)-mediated and a palladium(II)-catalyzed intramolecular alkoxycarbonylation were used as key steps for the preparation of the two cis-2,6-disubstituted tetrahydropyran rings (C22-C26 and C11-C15) of phorboxazole A. The synthesis used a convergent approach involving...
Resource Type:: Dissertation
Full Text:: produced 32 exclusively with (E) configuration at the C19-C20 double bond. O NCl HO OTBDPS 30 O

Tandem intramolecular photocycloaddition-retro-Mannich fragmentation as a route to indole and oxindole

Creator:: Li, Yang
Abstract:: Irradiation of a tryptamine linked through its side-chain nitrogen to an alkylidene malonate residue results in an intramolecular [2 + 2] cycloaddition to the indole 2,3-double bond. The resultant cyclobutane undergoes spontaneous retro-Mannich fission to produce a spiro[indoline-3,3-pyrrolenine] with relative configuration defined by the orientation of substituents in the transient...
Resource Type:: Dissertation
Full Text:: photoexcitation of a conjugated system to a singlet excited state. The O + hν O H H H + (E) and (Z

Approaches to the synthesis of trichothecenes

Creator:: Kim, No-soo
Resource Type:: Dissertation
Full Text:: relative stereochemistry at the two quaternary centers C5 and C6.21 HO Scheme 7 Masuoka and Kubota21 a

The synthesis of nonactic acid

Creator:: Arco, Manuel Jose
Abstract:: Alkylation of propylene oxide with 2-lithiofuran gave alcohol I, which was smoothly converted to acetylfuran II. hydrogenation of II over rhodium on charcoal followed by Jones' oxidation afforded ketone III. Further transformation into IV was accomplished via a Wittig reaction followed by saponification with methanolic sodium hydroxide. Hydroboration of the...
Resource Type:: Dissertation
Full Text:: . AcO 1) c03 P = CH2 2) NaOH, CH3OH 77% Bu Li, 9 7 % 1) H2, Rh/C 2) Jones' reagent 100% HO H

Synthetic studies n bioactive natural products. Part I, An approach towards the nootrophic agent huperzine A. Part II, Synthesis of the tricarbonyl subunit of rapamycin

Creator:: Jeffrey, Scott C.
Resource Type:: Dissertation
Full Text:: 364a and 364b 140 This dissertation is dedicated to my Mother and Father, Saundra E. and Gerald

The isolation and structure of leptosphaerin : a metabolite of the marine ascomycete, Leptosphaeria oraemaris (Linder) and A synthesis of the marine toxin, 9-isocyanopupukeanane

Creator:: Schiehser, Guy Alan
Abstract:: The ethyl acetate extract of the culture filtrate of the marine Ascomycete, Leptosphaeria oraemaris (Linder) yielded a novel metabolite designated by the common name leptosphaerin. An x-ray crystallographic structure analysis was disproved by the synthesis of 3-acetoxy-S-(1,2-dihydroxyethyl)- 3-pyrrolin-2-one 1, starting with N,N-dibenzylhydroxylamine 47 and D-mannitol 44. Oxidation of 47 followed...
Resource Type:: Dissertation
Full Text:: . Structure Elucidation C. Synthesis of the Putative Leptosphaerin D. Experimental E. Bibliography 1 4 9

Synthesis of a model of the spiroketal portion of avermectin B

Creator:: Warrier, Ulhas S.
Abstract:: Avermectin Bia is a member of a class of medicinally important natural products known for its potent antiparasitic activity and interesting structural features. In this thesis, synthesis of a model for the spiroketal portion of the avermectins is presented. Oxidation of (S)-2-methylbutanol, followed by a stereoselective chromium mediated reaction with...
Resource Type:: Masters Thesis
Full Text:: stimulated by avermectin B1 is GABA-mediated, this HO,.. OMe OMe HO, OMe HO 30 iii HO... OH OH 3

Synthetic studies on alkaloids : part I; asymmetric synthesis of (±) codeine. Formal synthesis of (±) morphine : part II; a unified asymetric approach toward synthesis of polyhydroxylated pyrrolizidine alkaloids, australine and alexine

Creator:: Hrnciar, Peter
Resource Type:: Dissertation
Full Text:: degree of Doctor of Philosophy Completed August 18, 1998 Commenced Jun e 1999 Doctor of Philosophy

Cis-2,5-diaminobicyclo[2.2.2]octane : a novel C₂-symmetric scaffold for asymmetric catalysis

Creator:: Shaw, Subrata
Abstract:: This thesis describes the development of a new enantioselective synthetic method employing chiral cis-2,5-diaminobicyclo[2.2.2]octane-based organometallic catalysts. The significance of this new method to organic synthesis is illustrated with preparation of enantioenriched products that are transformed to important pharmaceutical agents. Chapter 1 provides a brief historical overview of asymmetric catalysis, especially...
Resource Type:: Dissertation
Full Text:: enzyme present in vivo, converts the (R) e n anti o me r of 6 to the active (S)-enantiomer.4 / NH 0 0

ScholarsArchive@OSU

Synthetic studies on marine natural products : I. Stereoselective synthesis of E,Z-1,3-Dienes by tandem nucleophilic addition to a dienylphosphonium salt followed by Wittig reaction. II. Synthesis of cyclopropyl oxylipins by a cation mediated carbocyclization

Approaches to the total synthesis of verrucarol

Studies towards the total synthesis of (-)-kendomycin

Absolute stereochemistry and total synthesis of botryococcene

Chiral synthesis of monic acid C

Approaches to the synthesis of the macrolactone pyrrolizidine alkaloids (-)-integerrimine and (+)-usaramine

Synthetic studies on alkaloids : part I, an approach toward the synthesis of (̳+)-koumine : part II, an approach toward the synthesis of (̳+)-morphine

An approach toward the synthesis of euonyminol and cathedulin K- 19

Studies toward the total synthesis of sanglifehrin A

Approaches to the synthesis of methymycin

Phenolic oxidative coupling : an approach to the synthesis of pretazettine

Total synthesis of phorboxazole A

Tandem intramolecular photocycloaddition-retro-Mannich fragmentation as a route to indole and oxindole

Approaches to the synthesis of trichothecenes

The synthesis of nonactic acid

Synthetic studies n bioactive natural products. Part I, An approach towards the nootrophic agent huperzine A. Part II, Synthesis of the tricarbonyl subunit of rapamycin

The isolation and structure of leptosphaerin : a metabolite of the marine ascomycete, Leptosphaeria oraemaris (Linder) and A synthesis of the marine toxin, 9-isocyanopupukeanane

Synthesis of a model of the spiroketal portion of avermectin B

Synthetic studies on alkaloids : part I; asymmetric synthesis of (±) codeine. Formal synthesis of (±) morphine : part II; a unified asymetric approach toward synthesis of polyhydroxylated pyrrolizidine alkaloids, australine and alexine

Cis-2,5-diaminobicyclo[2.2.2]octane : a novel C₂-symmetric scaffold for asymmetric catalysis

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