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Filtering by: Creator Reid, J. Leighton Remove constraint Creator: Reid, J. Leighton Advisor White, James D. Remove constraint Advisor: White, James D.

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  • Synthesis of metabolites from the ascomycetes : I. The synthesis and absolute configuration of leptosphaerin : II. Approaches to the synthesis of byssochlamic acid

    Creator:
    Pallenberg, Alexander J.
    Abstract:
    Part I. The total synthesis of (+)-leptosphaerin (2), a metabolite of the marine Ascomycete Leptosphaeria Oraemaris (Linder) was achieved, unambiguously establishing both the relative and absolute stereochemistry of this natural product. This synthesis also resolved the long-standing question of which of the isomeric structures 1 or 2 correctly represents the...
    Resource Type:
    Dissertation
    Full Text:
    AN ABSTRACT OF THE THESIS OF Alexander J. Pallenberg for the degree of Doctor of Philosophy in

  • 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:
    more likely structure. 4 02H 6 J 6 2 C 02Me 7 3 CO2H 1 10 st 4 1 10 O2Me 59a 59b Figure 2.6: Two

  • Studies toward the total synthesis of phorboxazole A

    Creator:
    Kuntiyong, Punlop
    Abstract:
    Studies toward the total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, were conducted and resulted in a route to an advanced intermediate, C4-C32, for this purpose. A key feature of our approach is the stereoselective synthesis of two cis-2,6-disubstituted tetrahydropyrans present in the macrolide portion of...
    Resource Type:
    Dissertation
    Full Text:
    Although 8 is antipodal to I, compound 8 exhibits a vicinal H37-H38 coupling (J = 8.0 Hz, CDCI3) which

  • 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:
    /MeCN (1:1), rt, 24h Scheme 12 12 References 1 (a) Searle, P. A.; Molinski, T. F. J. Am

  • Natural product synthesis via cyclobutanes : part I, Asymmetric synthesis of (+)-byssochlamic acid, part II, An approach to the nootropic agent huperzine A

    Creator:
    Kim, Jungchul
    Abstract:
    PART I. Asymmetric syntheses of both natural (+)- and nonnatural (-)-byssochlamic acid via a [2+2] photoaddition-cycloreversion strategy are described. X-ray crystallographic analysis of the cyclohexylamine salt 99 showed that the structure of the monomethyl ester 100 from esterase hydrolysis of 44 was originally misassigned as 56. The enantiomeric relationship of...
    Resource Type:
    Dissertation
    Full Text:
    Deerberg, Duncan J. Wardrop, Carla Hassler, Sung-kee Kim, Christine S. Nylund, Scott J. Kemp, Roger

  • 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:
    cyclosporine A 1.4 References 1. Fehr, T.; Oberer, L.; Ouesniaux Ryffel, V.; Sanglier, J.-J.; Schuler, W

  • Approaches toward the asymmetric synthesis of pillaromycin A

    Creator:
    Nolen, Ernest G.
    Resource Type:
    Dissertation
    Full Text:
    ; i.NaBH4, CeC13, Me0H; j.TBDMSi-triflate, 2,6-lutidine, CH2C12; k.2100C h i,j k 58 OAc the (-endo

  • Synthesis of two subunits of avermectin B1a

    Creator:
    Dantanarayana, Anura Pathmasiri
    Abstract:
    Avermectins are a group of potent anthelmintic agents produced by Streptomyces avermitilis. They are active at extremely low dosages and are now in commercial use. In this study, the synthesis of two segments of avermectin B[subscript 1a] are described. The synthesis of the hexahydrobenzofuran subunit (segment A) began with the...
    Resource Type:
    Dissertation
    Full Text:
    , yielded the hexahydrobenzfuran 36 (Scheme 4). A few months after the Fraser-Reid communication appeared

  • The synthesis of macrolactones from [omega]-hydroxyacyl xanthates

    Creator:
    Akella, Annapoorna
    Resource Type:
    Masters Thesis
    Full Text:
    , leading ultimately to a lactone 46 and xanthic acid 47 (Scheme IX). Scheme IX 0 S 0 CLI SA0Et ?j. S OH

  • Studies towards the total synthesis of (-)-gymnodimine

    Creator:
    Wang, Guoqiang
    Abstract:
    Studies towards the total synthesis of (-)-gymnodimine (1), a marine neurotoxin with a unique molecular architecture and pronounced biological activity, are described. These studies resulted in a convergent approach to the advanced intermediate 315, containing the C3-C32 section of 1. Two synthetic routes were developed to construct the tetrahydrofuran subunit...
    Resource Type:
    Dissertation
    Full Text:
    among the most potent toxins in the mouse bioassay. Pinnatoxin D (LD50> 10 j..tgIMU) showed less potent