Five-Membered Ring Systems

Cordero, Franca M.; Giomi, Donatella; Lascialfari, Luisa

doi:10.1016/b978-0-08-102788-2.00011-8

Cited by 8 publications

(2 citation statements)

References 139 publications

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“…There are several other reaction types that can be used for this purpose. Particularly molecules containing 5-membered aromatic rings with 2 or 3 heteroatoms (oxazoles, isoxazoles, oxadiazoles, triazoles etc) may be prepared not by connecting the 2 aromatic rings, but by various heterocyclization reactions (Cordero, Giomi, and Lascialfari 2018;Baumann et al 2011), for example by 1,3-dipolar cycloaddition. To filter out such cases the list of "preferred Suzuki substrates" obtained previously by processing the reactions described in patents (Figure 1) was used.…”

Section: Boronic Acids Used In the Synthesis Of Bioactive Moleculesmentioning

confidence: 99%

Which boronic acids are used most frequently for synthesis of bioactive molecules ?

Ertl,

Altmann,

Racine

et al. 2023

Preprint

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Boronic acids are essential building blocks used for the synthesis of bioactive molecules, the generation of chemical libraries and the exploration of structure-activity relationships. As a result, more than ten thousand boronic acids are commercially available. Medicinal chemists are therefore facing a challenge; which of them should they select to maximize information obtained by the synthesis of new target molecules. The present article aims to help them to make the right choices. The boronic acids used frequently in the synthesis of bioactive molecules were identified by mining several large molecular and reaction databases and their properties were analyzed. Based on the results a diverse set of boronic acids covering well the bioactive chemical space was selected and is suggested as a basis for library design for the efficient exploration of structure-activity relationships. A Boronic Acid Navigator web tool which helps chemists to make their own selection is also made available at https://bit.ly/boronics.

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Section: Boronic Acids Used In the Synthesis Of Bioactive Moleculesmentioning

confidence: 99%

Which boronic acids are used most frequently for synthesis of bioactive molecules ?

Ertl,

Altmann,

Racine

et al. 2023

Preprint

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“…Introduction 2,3-Dihydroisoxazoles (often referred to as 4-isoxazolines) represent a very important class of N/O-containing heterocycles used as the key intermediates in the synthesis of more complex cyclic and acyclic compounds, including various biologically active molecules [1][2][3][4][5][6].…”

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confidence: 99%

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

Dikošová

Laceková

Zaborsky

et al. 2020

Beilstein J. Org. Chem.

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Isoxazolidines represent a very important class of N/O-containing heterocycles used as the key intermediates in the synthesis of more complex cyclic and acyclic compounds, including various biologically active molecules. Here, we present a fast and highly stereoselective approach towards both C-3/4-cis and C-3/4-trans isomers of 3-substituted isoxazolidin-4-ols. The strategy relies on a highly regio- and trans-stereoselective hydroboration–oxidation reaction of the 4,5-unsubstituted 2,3-dihydroisoxazoles with basic hydrogen peroxide. The consecutive oxidation/reduction route, sequentially employing Dess–Martin periodinane and ʟ-selectride, is used for the inversion of the C-3/4-trans relative configuration of the isoxazolidine ring. The significance of the method lies in its variability and applicability to a concise synthesis of various 4-hydroxyisoxazolidines, starting from the readily available C-alkyl/aryl-nitrones. The resemblance to 3-hydroxypyrrolidines certainly makes the 4-hydroxyisoxazolidines important and valuable structural fragments in drug discovery.

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Transition Metal‐Mediated Functionalization of Isoxazoles: A Review

2021

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Isoxazoles are an important class of heterocycles with nitrogen and oxygen in a 1,2-relationship. They find wide applications in synthetic organic chemistry and are part of several drug molecules. Since the last two decades, great progress has been achieved in the synthesis and functionalization of isoxazoles, in which transition metal catalysis played a pivotal role towards achieving this goal. In particular, the transition metal (TM)-mediated site-selective functionalizations of isoxazoles which retain the pharmacologically and synthetically valuable isoxazole skeleton, are highly appealing. This comprehensive review is solely dedicated to the TM-mediated functionalization of isoxazoles, wherein we have included isoxazoles as directing groups (DG) for TM-catalyzed CÀ H functionalization reactions, TM-catalyzed direct CÀ H functionalization, along with cross-coupling reactions of isoxazoles, TM-catalyzed annulation reactions of isoxazoles and finally ring-opening reactions of isoxazoles under TMcatalysis are also discussed. Also, incorporated are discussions on reaction designs, their advantages and limitations, mechanistic details and challenges that need to be addressed to inspire synthetic organic and medicinal chemists to explore new reaction arenas and make use of this key scaffold.Scheme 1. Synthetic approaches for functionalized isoxazoles.Scheme 2. Functionalization of isoxazoles via the 4-isoxazolyl anion species.

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Five-Membered Ring Systems

Cited by 8 publications

References 139 publications

Which boronic acids are used most frequently for synthesis of bioactive molecules ?

Which boronic acids are used most frequently for synthesis of bioactive molecules ?

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

Transition Metal‐Mediated Functionalization of Isoxazoles: A Review

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