Author: Barnett BernsteinPublisher:
ISBN:
Category : Alkaloids
Languages : en
Pages : 184
Book Description
Approaches to the Synthesis of Fawcettidine, a Lycopodium Alkaloid
Author: Barnett BernsteinPublisher:
ISBN:
Category : Alkaloids
Languages : en
Pages : 184
Book Description
Approaches to the Total Synthesis of the Lycopodium Alkaloid Fawcettimine and Related Studies
Author: Todd Andrew BlumenkopfPublisher:
ISBN:
Category :
Languages : en
Pages : 648
Book Description
An Approach to the Synthesis of Lycopodium Alkaloids
Author: Friedrich K. HessPublisher:
ISBN:
Category : Alkaloids
Languages : en
Pages : 0
Book Description
Lycopodium Alkaloids
Author: Jerold Steven HornPublisher:
ISBN:
Category : Alkaloids
Languages : en
Pages : 150
Book Description
Unified Approach to the Lycodine Lycopodium Alkaloids
Author: Michael David PurdhamPublisher:
ISBN:
Category :
Languages : en
Pages : 198
Book Description
A Unified Approach Toward the Total Synthesis of Lycopodium Alkaloids of the Miscellaneous Class
Author: Sarah Elizabeth HousePublisher:
ISBN:
Category :
Languages : en
Pages : 370
Book Description
A unified approach to the total synthesis of Lycopodium alkaloids belonging to the miscellaneous class has been developed, wherein a single tetracyclic amine is employed as a common intermediate in synthetic studies toward several alkaloids. An overview of Lycopodium alkaloids is presented, including their structural classification, isolation and biological activity. The biosynthesis of alkaloids in the miscellaneous group is discussed in depth. A summary of previous synthetic work focusing on miscellaneous Lycopodium alkaloids is presented, including total syntheses of luciduline, lyconadins A and B and nankakurines A and B.A model study of spirolucidine is discussed. A biomimetic route to access spirolucidine and nankakurine B has been investigated. In this study, a tetracyclic amine that is a key intermedite in the total synthesis of lyconadin A previously developed in our laboratory is elaborated into a tertiary alcohol that mimics the proposed biosynthetic precursor of nankakurine B.A biomimetic ring-contractive [alpha]-hydroxyimine rearrangement to generate nankakurine B has been extensively investigated and found to be disfavored. The conversion of a tricyclic ketone (first synthesized en route to lyconadin A) to the tetracyclic core of serratezomine D has been investigated. The core of this molecule was inaccessible via methods employed in the studies toward lyconadin A. The total synthesis of 1'-epi-dihydrolycolucine from the key common tetracyclic amine intermediate has been achieved. Studies toward the synthesis of serratezomine E served as a platform to develop this method and to determine the stereochemical outcome of this reaction.
An Approach to the Synthesis of Lycopodium Alkaloids
Author: George Alexander CookePublisher:
ISBN:
Category : Alkaloids
Languages : en
Pages : 0
Book Description
The compound N-acetyl-2-chloro-2-(3~aminopropyl)- cyclohexanone (LXXXI) has been prepared by the alkylation of the pyrrolidine enamine of cyclohexanone, followed by hydride reduction of the corresponding ethylene ketal, acetylation, hydrolysis of the ketal, and chlorination of the resulting N-acetyl ketone. In a more direct approach to a lycopodine system, a series of hexahydrojulolidine derivatives, oxygenated at C-9 and carrying a substituent at C-ll, were prepared. Thus Birch reduction of 9-methoxyjulolidine XXVIII yielded the dihydro-derivative XXXVI which on treatment with ethylene glycol and perchloric acid was converted to the ethylene-ketal iminium perchlorate XCVIII, This substance was then subjected to the conditions of the Grignard reaction using methallyl magnesium chloride (CVII) to produce the corresponding C-ll adduct as two stereoisomers CX (all trans) and CXI (all cis), the latter being the major product. Pure CXI was obtained by column chromatography and experiments were carried out to deter-* mine its stereochemistry. Treatment of the CXI (as its perchlorate) with ozone followed by catalytic reduction of the ozonide produced the ketone CXXIII and several attempts were made to convert this to the annotinine II skeleton by photochemical methods. Reactions were as well performed designed to introduce unsaturation at C-7a, 8 thus providing a compound which might be expected to produce the cis-trans isomer (CXLIV) on dissolving metal reduction> The mass spectra of several of these derivatives were measured and are interpreted by analogy with fragmentations observed in several Lycopodium alkaloids.
A Biogenetic Approach to the Synthesis of the Lycopodium Alkaloids
Author: Gregory Wayne SchwingPublisher:
ISBN:
Category :
Languages : en
Pages : 140
Book Description
Toward the Synthesis of the Magellaninone- and Lycopladine-type Lycopodium Alkaloids
Author: Rebecca Anne MurphyPublisher:
ISBN:
Category :
Languages : en
Pages : 340
Book Description
This dissertation describes our strategy toward the synthesis of a variety of fawcettimine-type Lycopodium alkaloids. The first section focuses on the classification, structure, and historical significance of these natural products. This section also includes a proposal for their biosynthesis and a survey of the biological activities of the members of this class. The second section describes our work toward magellanine, magellaninone, and paniculatine. Two existing syntheses of these molecules are discussed, along with the strategy that we chose to employ in our work. We first pursue the synthesis of these natural products using a C4 pyridine C-H functionalization strategy that is based on precedent by the Fagnou and Echavarren groups. We then describe a C3 pyridine C-H functionalization approach that has more diverse methodological inspiration, although the original synthetic disconnection strategy derives from work done by the Jin Quan Yu group. Both of these synthetic endeavors are detailed herein. Finally, the third section covers our efforts toward the synthesis of lycopladines B, C, and D. We describe our "Heathcock-inspired"cascade approach toward the divergent synthesis of these three natural products. In this work, we have pursued the synthesis of a number of different substrates. We conclude with a summary of how this approach has evolved into a number of other projects within our group.
Synthesis of Lycodine-Type Lycopodium Alkaloids Using C-H Functionalization Tactics
Author: James NewtonPublisher:
ISBN:
Category :
Languages : en
Pages : 97
Book Description
This dissertation describes our syntheses of several lycodine-type Lycopodium alkaloids by the late-stage C-H functionalization of lycodine derivatives. Lycodine-type alkaloids are well-known for their neurological activity. For example, huperzine A is a potent acetylcholinesterase inhibitor and the complanadine family of molecules has been shown to induce the secretion of Nerve Growth Factor. Due to these properties, lycodine-type alkaloids serve as interesting lead compounds for the development of new therapies for neurodegenerative disorders, such as Alzheimer's disease. Unsurprisingly, these molecules have attracted the attention of the synthetic community. Chapter 1 reviews syntheses of lycodine-type Lycopodium alkaloids with particular emphasis on the syntheses of biologically active congeners. Chapter 2 describes our synthesis of complanadine B, an unsymmetrical dimer of lycodine, using two approaches. In the first, the requisite skeletal oxygenation was installed early in the synthetic sequence. Our second approach utilized a blocking group strategy to enable the late-stage oxygenation of the complanadine skeleton by preventing oxygenation at undesired sites. Chapter 3 describes our efforts toward the synthesis of the casuarinine family of Lycopodium alkaloids by the late-stage C-H functionalization of lycodine derivatives. Using this strategy, we have been able to complete the synthesis of casuarinine D and have made significant progress toward the synthesis of casuarinine H, which we believe can serve as an intermediate in the synthesis of several other lycodine-type alkaloids.