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Showing 1 to 20 of 61 for “"Ring Systems"”.
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Conformational behaviour of selected silicon- and germanium-containing ring systems
… indicated equatorial preference. During this project three 1-silacyclohexanes derivation were synthesized with the purpose to be investigated by means of dissociative electron attachment measurements. These measurements were performed by prof. O. Ingólfson's research group at the …
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Multi-Configurational Investigation of Thermolytic Pathways of Highly Strained Ring Systems
… of the activation barriers in these systems. The two model systems of benzvalene and dihydrobenzvalene have been explored previously. These tricyclic structures were shown to be able to undergo a pericyclic ring opening mechanism. That particular process can either occur in either a …
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Preliminary studies in the synthesis of the polynuclear hydroaromatic ring systems
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1936.
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Synthetic and computational investigations into reaction pathways towards complex heterocyclic ring systems
Tetrazocines are eight-membered rings possessing four nitrogen atoms. The development of new synthetic routes to novel heterocyclic systems has remained a critical branch of synthetic organic chemistry due to potential applications in biomimetics and pharmaceuticals, such as dyes and explosives. …
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The synthesis and properties of some higher membered fused alicyclic ring systems
Because of the theoretical interest in the ring system consisting of two-fused fully unsaturated seven-membered rings (Wilson Baker, Tilden lecture J. 1945, 268), for which the trivial name "heptalene" is suggested, attempts have been made to synthesise this hydrocarbon to study its chemical and …
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Synthesis of multicyclic ring systems including an alternate route to Meyers’ lactam derivatives
… which includes the 1-azobicyclo[3.1.0]-hexane ring system and were originally isolated from Streptomyces sahachiroi and later from Steptomycetes griseofucus. Their structures were defined in 1983 and since then there has been significant international competition in total synthesis of …
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Self - Condensation of Polyfunctional Molecules as a Route to Certain Alkaloid Ring Systems
Made available in DSpace on 2014-12-05T19:37:19Z (GMT). No. of bitstreams: 1 6001617.pdf: 4035663 bytes, checksum: 769083ce4ba55377702dd73d1e265bc0 (MD5) Previous issue date: 1960
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Exploration of Synthetic Pathways to Quaternary Carbon Stereocenters and Fused Ring Systems via Birch Reductions
… 6-5-6 and 6-6-6 carbocyclic and heterocyclic systems. In all of these examples the Birch reduction alkylation has been the key step and we have demonstrated broad applicability and the use of some of the most complex alkylating agents to date.</p>
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NOVEL HETEROCYCLIC RING SYSTEMS DERIVED FROM CARACURINE V AS LIGANDS FOR THE ALLOSTERIC SITE OF MUSCARINIC M 2 RECEPTORS
… Die relative Stellung der aromatischen Indolringe und der Abstand zwischen den positiv geladenen Stickstoffatomen (ca. 10) in dem sehr starren Caracurin-V-Ringsystem definieren den Pharmakophor für potente allosterische Modulatoren. Caracurin-V-Salze sind strukturell sehr verwandt mit den …
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Explorations in Supramolecular Chemistry: Part 1. Development of a Modular System for the Study of Self-Organization Through Microphase Segregation in Discotic Liquid Crystals. Part 2. Investigation of Deazapterins and Naphthyridines as End-Groups for Supramolecular Polymers
… and 2,7-diamino-[1,8]-naphthyridine ring systems were pursued. While it was found that the end-groups could be made, the synthetic difficulties and inefficiencies encountered precluded the isolation of sufficient sample quantities for the exploration of the materials' properties. The …
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Dioxycarbenes and 3,3-Dioxyvinylcarbenes in the Synthesis of Novel Heterocycles
… Therefore, the discovery and development of new ring forming reactions are of paramount interest to synthetic organic chemists. Recently, the intramolecular cyclization of reactive intermediates, such as anions, cations, and radicals have provided a number of new methods by which known and novel …
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QUANTUM TRANSPORT WITH COLD ATOMS
… of atomic circuits. The current flowing through ring systems attached to leads are known to be modulated by applied gauge fields. We show that this so-called Aharonov-Bohm effect is absent for bosonic atoms. Within atomic Y-junctions, we find negative reflections that resemble Andreev-reflections …
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Studies in the synthesis of pyrimidines, pyrazoles, and pyrazolo pyrimidines. New syntheses of 1, 3 and 5 substituted pyrazolo [3, 4-d] pyrimidines, including glycosides related to naturally occurring pyrimidines, imidazoles, purines and their nucleoside derivatives.
… analogous to those found in naturally occurring systems, are found to possess chemotherapeutic activity. Some, in the form of their nucleoside or nucleotide derivatives, are valuable antimetabolites in that they may block normal RNA or DNA polymerisation, or may be incorporated into nucleic …
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Dynamics of Dipoles in the Middle Atlantic Bight
… with the observations made by the Warm-Core Rings program in the early 1980's, several Gulf Stream warm-core rings (WCR's) in the Middle Atlantic Bight (MAB) have been observed with one or more cyclones around their periphery. These ring systems are observed in the slope water between the …
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The synthesis and reactivity of 3-amino and 3-oxycyclopentadienones
… [4.3.0], and [5.3.0] bicyclic-cyclopentadienone ring systems. In an effort to probe the reactivity of our metal complexed dienones, we proceeded to subject them to cycloaddition reactions. With this goal in mind, we applied oxidative demetallation conditions to provide the metal free …
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The synthesis and benzannulation reactions of (trialkylsilyl)vinylketenes
… reaction proceeds by formation and electrocyclic ring closure of 3-oxidodienylketene intermediates, followed by an intramolecular 1,3-silyl migration to provide highly substituted 3-siloxy phenols. Further transformations of these products providing efficient access to ortho-benzoquinones and …
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Development of Novel Nicotinic Receptor Mediated Therapeutic Agents: Synthesis and Biological Evaluation of Novel Epibatidine Analogs and the First Total Synthesis of Anabasamine and Related Analogs
… 1-(pyridyloxymethyl)-7-azabicyclo[2.2.1]heptane ring systems were furnished via an intramolecular cyclization from a trans 1, 4 disubstitituted amino-cyclohexane derivative. The functionalized cyclohexane ring was formed via a [4+2] Diels-Alder cyclization reaction between the acetamidoacrylate …
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Targeting the tumor microenvironment through the design and synthesis of potent, small-molecule, anticancer agents.
… analogues incorporate a [6,7] fused ring system with an aryl ring attached at the 5-position. The initial discovery in the Pinney Research Group of the benzosuberene lead compound 1-hydroxy-2-methoxy-5-(3',4',5'-trimethoxyphenyl)benzocyclohept-5-ene 1, has led to research focused on …
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Cascade Approaches to Polycyclic Natural Products
… of considerable difficulty, such as rigid fused-ring systems and quaternary chiral centers, has been applied to the chosen molecules. The results of these studies have demonstrated the power of cascade-based core formation to rapidly assemble complex, polycyclic architectures in two different …
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