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  • Approaches to the synthesis of polyketides. Vermiculine

    Creator:
    Kirkemo, Curtis Lee
    Abstract:
    An approach to the generation of polyketides was investigated, which involved ozonolysis of 6, 7 cyclopenteno -1> 4, 5, 8 -tetrahydromethoxy- 3-methylnaphthalene (26), to produce what is believed to be polyketide 27. Compound 26 was formed by the following sequence: Die ls -Alder addition of 1, 2 -dim.ethylenecyclopentane and 2...
    Resource Type:
    Dissertation
    Full Text:
    scheme have not been established. O 0 ,,> /COON Scheme 4. EtO +12 14 H+ COOEt HO COOEt 15

  • Synthesis of marine natural products. part I, Cryptophycins-1, -3, -4, -24, and -29, part II, Polycavernoside A

    Creator:
    Robarge, Lonnie A.
    Resource Type:
    Dissertation
    Full Text:
    , cryptophycin-3) 4, R = Me, X = H(cryptophycin D, cryptophycin-4) 6, R = H, X = CI(cryptophycin-29) Figure 1.1

  • 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:
    ) 4 Avermectin Alb Me Me CH2 -CH(OH) 5 Avermectin Bia H Et CH = CH 6 Avermectin Bi b H Me CH = CH 7

  • 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:
    conformation. 15 LiAIH4 Et20 (15)R=Ac (16)A =H (17) R = COCH2Br OH 4 1 : 1 Scheme 2 OH 18 Cathedulins

  • 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:
    missing. There is also a change in the keto-enol status of the uracil moiety. 4 H H o Ny~H NyNH H

  • Asymmetric synthesis of cyclopropanes via a "zipper reaction"

    Creator:
    Lincoln, Christopher M.
    Abstract:
    The rearrangement of a homoallyl cation to a cyclopropylcarbinyl cation is thought to play a role in the biogenesis of a variety of cyclopropane-containing natural products,¹ a hypothesis which has previously led to the design of successful biomimetic syntheses of several natural products.² The strategy underlying this approach to cyclopropane...
    Resource Type:
    Dissertation
    Full Text:
    (Scheme 4). CO2Me CH2 8,9, 10 CO2Mel47c J 12 CO2Me1[v/H 13 / CO2Me [ 14 6 / CO2Me I Scheme

  • Studies toward the total synthesis of (+)-providencin

    Creator:
    Jana, Somnath
    Abstract:
    Studies toward the total synthesis of (+)-providencin (1), a highly oxygenated cembranoid dipterpene with a unique bicyclo[12.2.0]hexadecane skeleton and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediates 320 and 332 which contain all of the carbon atoms of 1. In a first generation approach...
    Resource Type:
    Dissertation
    Full Text:
    to couple the two major fragments, 228 and 288, using palladium-catalyzed C-H activation of the

  • Alkylation studies on Hagemann's ester: an approach to the synthesis of the trisporic acids

    Creator:
    Sung, Wing Lam
    Abstract:
    Sequential alkylation of Hagemann's ester with methyl and methallyl halides has been studied. Treatment of Hagemann's ester with methyl iodide and sodium ethoxide gave a mixture of 21 and 25 in a ratio of 4:1. Alkylation of 21 with methallyl chloride and potassium t-butoxide afforded a mixture of 37 and...
    Resource Type:
    Masters Thesis
    Full Text:
    produced a mixture of 29 (two CH3, 6 1. 62) and 30 (vinyl H, 6 4. 97, doublet) in a ratio of 1:1 (yield 75

  • 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:
    June 4, 1986. Title: Approaches to the Total Synthesis of Verrucarol Abstract approved: Redacted for

  • Synthesis of furanoeremophilane sesquiterpenoids

    Creator:
    Shanmugham, Meenakshi Sundaram
    Abstract:
    Two approaches to the tricyclic core of the furanoeremophilane sesquiterpenoids are described. The first approach entails a projected Diels-Alder/retro Diels-Alder reaction of an acetylenic oxazole 64. Construction of the pivotal aldehyde 67 commenced from ketone 68. The acetyenic moiety was then introduced via a Felkin-Ahn addition of lithiopropyne to aldehyde...
    Resource Type:
    Dissertation
    Full Text:
    : Petasalbine 8: Senemorin R = angelate 9: R = H 0 OH 3: Euryopsin 4: 63-Hydroxyeuryopsin 6: Ligularone 7