Chemistry of quinuclidines as nitrogen bicyclic bridged‐ring structures

Hamama, Wafaa S.; El-Magid, Osama. M. Abd; Zoorob, Hanafi H.

doi:10.1002/jhet.5570430601

Cited by 15 publications

(4 citation statements)

References 93 publications

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“…The enamine is reprotonated at nitrogen under the reaction conditions, but the basic workup gives the final neutral product. Other bridged enamines based on the quinuclidine skeleton − have been reviewed. , …”

Section: Synthesis Of Bridged Lactams With Complex Ring Systems and R...mentioning

confidence: 99%

Chemistry of Bridged Lactams and Related Heterocycles

2013

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CONTENTS 1. Introduction 5702 2. General Properties of Bridged Lactams 5703 2.1. Distortion Parameters of Bridged Lactams 5703 2.2. Bond Lengths of Bridged Lactams 5703 2.3. Spectroscopic Properties of Bridged Lactams 5703 2.4. Analogy of Bridged Lactams to Bridgehead Olefins 5704 2.5. Chemical and Biological Significance of Distorted Amides 5704 3. Synthesis of Historically Important Bridged Lactams 5704 3.1. Quinuclidone Derivatives 5704 3.2. Adamantanone Derivatives 5707 4. Synthesis of Bridged Lactams with the N−(CO) Bond on a Two-Carbon or Larger Bridge, ([m. (≥2).n] Type) 5708 4.1. Condensation Reactions Forming the N− C(O) Bond 5708 4.2. Heck Reactions 5711 4.3. Diels−Alder Reactions 5712 4.4. Carbene Insertion Reactions 5713 4.5. Reactions via Radical Intermediates 5714 4.6. Miscellaneous Examples 5714 5. Synthesis of Bridged Lactams with the N−(CO) Bond on a One-Carbon Bridge, ([m.1.n] Type) 5715 5.1. Carbene Insertion Reactions 5715 5.2. Schmidt Reactions 5716 5.3.

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Section: Synthesis Of Bridged Lactams With Complex Ring Systems and R...mentioning

confidence: 99%

Chemistry of Bridged Lactams and Related Heterocycles

2013

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“…In this regard, great efforts have been devoted to the development of new methods toward the preparation of quinuclidine derivatives. 9 Traditionally, quinuclidine scaffolds can be constructed by second-order nucleophilic substitution (S N 2) reaction or condensation reaction of piperidine derivatives. [10][11][12] However, most of these reactions are racemic or chiral auxiliary-assisted processes.…”

Section: Introductionmentioning

confidence: 99%

Highly Diastereo- and Enantioselective Synthesis of Quinuclidine Derivatives by an Iridium-Catalyzed Intramolecular Allylic Dearomatization Reaction

et al. 2019

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Asymmetric construction of quinuclidine derivatives has been realized by an iridium-catalyzed allylic dearomatization reaction. The catalytic system, derived from [Ir(cod)Cl] 2 and the Feringa ligand, tolerates a broad range of substrates. A large array of quinuclidine derivatives can be obtained under mild conditions in good to excellent yields (68%–96%), diastereoselectivity (up to >20/1 dr), and enantioselectivity (up to >99% ee). These products feature versatile functional group diversity and can undergo diverse transformations. A model that accounts for the origin of the stereoselectivity has been proposed based on density functional theory (DFT) calculations.

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“…However, several kinds of potent ligands for σ 1 receptor are known that are devoid of a terminal aromatic ring, provided that the basic nitrogen is joined to the aromatic head through a long linker (131 [47,51]) or is embodied in a bulky moiety, like the bicyclic quinolizidine (132 [52,53]) or the 3,3-dimethylpiperidine (133 [54]). Moreover, several kinds of spiro derivatives of N-methylpiperidine (134) or, even better, of 3-spiro derivatives of quinuclidine (135, 136) have been shown to exhibit central muscarinic activity or an agonistic effect on the α 7 nicotinic receptor [55][56][57][58], which is useful in cognitive enhancement (Figure 11). The structure of the obtained azo compound 130 is soundly supported by UV 1 H-NMR, 13 C-NMR and DEPT spectra, while the sequence leading to its formation is just one of those that could be envisaged [36].…”

Section: Affinity To Sigma Receptorsmentioning

confidence: 99%

3,3-Disubstituted 3,4-Dihydro-1,2,4-benzotriazines: Chemistry, Biological Activity, and Affinity to Sigma Receptors

Sparatore,

Sparatore

2023

Molecules

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By reducing the 2-nitrophenylhydrazone of cyclohexanone with sodium dithionite, an unexpected yellow compound was obtained instead of the corresponding colorless amino derivative. Many years later, the structure of this compound, namely, cyclohexane-3-spiro-3,4-dihydro-1,2,4-benzotriazine, was demonstrated. From that time, the reduction of 2-nitrophenylhydrazones of different kinds of ketones, followed by air oxidation of the initially formed amino compounds, has represented a general way to synthesize a variety of 3,3-disubstituted 3,4-dihydro-1,2,4-benzotriazines. Many derivatives have been obtained so far by a single research group, and most of them have demonstrated interesting pharmacological activities, mainly antihypertensive, anti-inflammatory, and diuretic effects and other activities with lower diffusion. Moreover, 3,3-disubstituted 3,4-dihydro-1,2,4-benzotriazines represent a novel class of ligands for sigma receptors, with nanomolar affinity to the σ1 subtype. This property might promote the development of agents for cardiovascular, neurodegenerative, and proliferative pathologies. The present commentary, by collecting compounds and biological results obtained so far, intends to celebrate the centennial of the discovery of the first member of this class of compounds and to promote further investigation in the field.

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Chemistry of quinuclidines as nitrogen bicyclic bridged‐ring structures

Abstract: This review summarises the structure, basicity, asymmetric organocatalysis, synthesis and reactions of quinuclidines. Quinuclidines are bicyclic saturated pyridin-containing compounds with rigid structures and a ring-juncture nitrogen atom. This review covers the period from 1984-2005.

Cited by 15 publications

References 93 publications

Chemistry of Bridged Lactams and Related Heterocycles

Chemistry of Bridged Lactams and Related Heterocycles

Highly Diastereo- and Enantioselective Synthesis of Quinuclidine Derivatives by an Iridium-Catalyzed Intramolecular Allylic Dearomatization Reaction

3,3-Disubstituted 3,4-Dihydro-1,2,4-benzotriazines: Chemistry, Biological Activity, and Affinity to Sigma Receptors

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