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Filtering by: Alternative title ssim Report no. 72-5 Remove constraint Alternative title ssim: Report no. 72-5 Advisor White, James D. Remove constraint Advisor: White, James D.

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  • Approaches to the synthesis of trichothecenes

    Creator:
    Kim, No-soo
    Resource Type:
    Dissertation
    Full Text:
    Abstract of the Thesis of No-Soo Kim for the degree of Doctor of Philosophy in Chemistry presented on

  • 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:
    for C 6 H 7 NO 3 : 141.043), 123 (72%), 99 (52%), 98 (31%), 70 (40%) and 43 (78%). 31

  • Approaches toward synthesis of the mycosporins

    Creator:
    Cammack, Janice H.
    Abstract:
    The mycosporins, formerly called P310's are secondary metabolites of fungi closely associated with fungal reproductive processes that require light. The structurally related iminomycosporins are found in marine plants and animals and may also have functions related to light. In this study, approaches toward the asymmetric synthesis of the mycosporins are...
    Resource Type:
    Dissertation
    Full Text:
    . Protection of (1R,2S13R15R)-1,2-0-cyclopentylidene-1,2,315- tetrahydroxy-5-hydroxymethylcyclohexane (39) and

  • Synthetic studies of nonadrides

    Creator:
    Drapela, Nicholas Ernest
    Abstract:
    An asymmetric approach to the synthesis of byssochlamic acid (1) is described. Regioisomeric enzymatic differentiation is described in the selective hydrolysis of dimethyl ester 30 by porcine liver esterase. Chiral dimethyl ester 42 was prepared by desymmetrization of cyclopentene 34 using porcine liver esterase. A key intramolecular [2+2]cycloaddition-cycloreversion photometathesis of...
    Resource Type:
    Dissertation
    Full Text:
    racemic diester was converted to monoacid. No other products were isolated except a small amount (<5%) of

  • Total synthesis of (-)-7-epicylindrospermopsin

    Creator:
    Hansen, Joshua D.
    Abstract:
    The first asymmetric synthesis of (-)-7-epicylindrospermopsin via intramolecular nitrone cycloaddition is described. The synthesis utilized a convergent approach to prepare the cycloaddition precursor 176, which was assembled by condensation of hydroxylamine 175 with aldehyde 145. Hydroxylamine 175 was synthesized from ethylene glycol (166) in seven steps. Aldehyde 145 was completed...
    Resource Type:
    Dissertation
    Full Text:
    oxazabicyclo[2.2.1 ]heptane derivative 177 accompanied by two unidentified stereoisomers in a ratio of 10:5

  • Synthetic approaches to the tricarbonyl subunit of rapamycin

    Creator:
    LaMunyon, James B.
    Abstract:
    Rapamycin (5) was isolated in 1975 from the soil bacteria Streptomyces hygroscopicus and its structure was determined from spectroscopic techniques and an x-ray crystallographic analysis. Although it was initially found to exhibit antibiotic activity, it was subsequently shown to possess potent immunosuppressive activity as well. Three approaches to the synthesis...
    Resource Type:
    Masters Thesis
    Full Text:
    Tricarbonyl Subunit of Rapamycin. Abstract approved: James D. White Rapamycin (5) was isolated in 1975

  • 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:
    its iodide. Methyl (2R)-3-hydroxy-2-methylpropionate was transformed into methoxy- methyl ( 5S)- 2, 5

  • The synthesis of trisporic acids

    Creator:
    Prisbylla, Michael Paul
    Abstract:
    A total synthesis of the fungal hormones, trisporic acids A and B, is described, starting from a -methyltetronic acid 34. A Robinson annelation of 34 with ethyl vinyl ketone affords the lactone 33. Treatment of 33 with N-bromosuccinimide gave 97, which was hydrolyzed to the lactol 103. The reaction of...
    Resource Type:
    Dissertation
    Full Text:
    hydrolysis, (±)-(7E, 9E)-trisporic acid B (3). Treatment of 3 with diazomethane afforded a 5% yield of

  • 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:
    mixture of (2S,3S,4R,5S)-2-(3-methyl)-(E)-carbo-t- butoxypropeny1)-3,4-cyclohexylidenedioxy-2H-pyran-5

  • Approaches to the synthesis of penicillin

    Creator:
    Furuta, Takuya
    Abstract:
    Several approaches to the synthesis of penicillin from 2-iminothioazolidine 50, from 2-thiothiazolidine 66 and by photocyclization of 77 and 78 were investigated. 2-Iminothiazolidine 50 was prepared from dibromoester 45 by the action of benzylamine followed by treatment of aziridine 46 with potassium or ammonium thiocyanate. Attempted introduction of a two-carbon...
    Resource Type:
    Dissertation
    Full Text:
    . 49; N, 12. 72. Found: C, 60. 13; H, 5. 75; N, 12. 51. 1, 3-Dibenzylhydantoin-2-thione (48) A