Palladium-Catalyzed Intramolecular Cyclization of Ynamides: Synthesis of 4-Halo-oxazolones

Huang, Hai; He, Guangke; Zhu, Guojing; Zhu, Xiaolin; Qiu, Shineng; Zhu, Hongjun

doi:10.1021/acs.joc.5b00071

Cited by 36 publications

(9 citation statements)

References 52 publications

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“…[41] Also, an intramolecular cyclisation of N-alkynyl alkyloxycarbamates with CuCl 2 or CuBr 2 ,i nt he presence of [Pd(PPh 3 ) 4 ], yields 4-halo-oxazolones with good functional group tolerance (Scheme 4b). [42] An intermolecular Suzuki-Miyaura CÀCc oupling and an intramolecular CÀOc oupling re-action within b,b-dibromoenamides affords 2-oxazolones and a-aminoketones (Scheme4c). [43]…”

Section: Synthetic Routes To Oxazoloned Erivativesmentioning

confidence: 99%

The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview

Singh

Silakari

2018

ChemMedChem

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O-Heterocycles have been explored in the field of medicinal chemistry for a long time, but their significance has not been duly recognised and they are often shunned in favour of N-heterocycles. The design of bioactive molecules for nearly every pathophysiological condition is primarily focused on novel N-heterocycles. The main reasons for such bias include the ease of synthesis and possible mimicking of physiological molecules by N-heterocycles. But considering only this criterion rarely provides breakthrough molecules for a given disease condition, and instead the risks of toxicity or side effects are increased with such molecules. On the other hand, owing to improved synthetic feasibility, O-heterocycles have established themselves as equally potent lead molecules for a wide range of pathophysiological conditions. In the last decade there have been hundreds of reports validating the fact that equally potent molecules can be designed and developed by using O-heterocycles, and these are also expected to have comparably low toxicity. Even so, researchers tend to remain biased toward the use of N-heterocycles over O-heterocycles. Thus, this review provides a critical analysis of the synthesis and medicinal attributes of O-heterocycles, such as pyrones, oxazolones, furanones, oxetanes, oxazolidinones, and dioxolonones, and others, reported in the last five years, underlining the need for and the advantages guiding researchers toward them.

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Section: Synthetic Routes To Oxazoloned Erivativesmentioning

confidence: 99%

The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview

Singh

Silakari

2018

ChemMedChem

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“…Cyclization of ynamides containing leaving groups such as Et and i Pr took place with poor yields (Table , entries 1 and 2). As we reported before, N ‐alkynyl tert ‐butyloxycarbamates are structures of great potential for the synthesis of cyclic carbamates, and N ‐alkynyl tert ‐butyloxycarbamate 6 ac reacted well to offer the desired product in good yield (Table , entry 3). Furthermore, N ‐carbobenzyloxy‐protected ynamide ( 6 ad ) furnished the corresponding product in 51 % yield, which is relatively lower than that obtained with 6 ac (Table , entry 4).…”

Section: Resultsmentioning

confidence: 57%

Generation of Oxazolidine‐2,4‐diones Bearing Sulfur‐Substituted Quaternary Carbon Atoms by Oxothiolation/Cyclization of Ynamides

Huang

Fan

et al. 2016

Chemistry A European J

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A novel method for metal-free oxothiolation of ynamides to construct oxazolidine-2,4-diones bearing sulfur-substituted quaternary carbon atoms has been developed. It represents a rare C-O bond cleavage of ynamides, as well as a facile and tandem approach for the formation of C-O, C-S, and C-Cl bonds. This redox-neutral protocol can be applied to the synthesis of multisubstituted oxazolidine-2,4-diones with good chemoselectivity and good yields of isolated products under mild conditions.

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“…Several oxazolone analogs have prepared using some reagents such as [(Ph 3 P)Au(NCMe)]Sb 6 complex [16], N,N'-terephthaloylbis-(dl-alanine) [17], resin [18], Ph 3 P-CBr 4 adducts [19], palladium [20] and others. In this study, a steroid-oxazolone derivative was prepared using some strategies; the first stage was achieved via reaction of 2-nitroestrone with acetonitrile to form an amino-ethanol complex (Figure 1 and 2).…”

Section: Chemical Synthesismentioning

confidence: 99%

Synthesis and theoretical activity evaluation of a new steroid-oxazolone derivative against COX1-1 and COX-2

2019

Biointerface Res Appl Chem

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There are some reports for the preparation of several drugs as cyclooxygenase (COX) inhibitors; however, some reagents used in the preparation are expensive and difficult to handle. The aim of this study was to synthesize a steroid-oxazolone derivativeusing some reactions such as i) hydroxylation-amiination; ii) amidation; iii) alkynyl-addition; iv) aldolization and iv) imination. In addition, a theoretical ass was carried out to evaluate the interaction of both COX-1 and COX-2 with the steroid-oxazolone derivativeusing indomethacin and rofecoxib as controls in a docking model. The structure of the compounds obtained was confirmed through elemental analysis, spectroscopy and spectrometry data. The results showed that there are differences between the interaction of the steroidoxazolone derivativewith both COX 1 and COX 2 compared with the bound of indomethacin and rofecoxib with this type of enzymes. These data suggest that the steroid-oxazolone derivativecould be a good candidate as COX-inhibitor translated as a possible drug for treatment of pain.

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Palladium-Catalyzed Intramolecular Cyclization of Ynamides: Synthesis of 4-Halo-oxazolones

Cited by 36 publications

References 52 publications

The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview

The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview

Generation of Oxazolidine‐2,4‐diones Bearing Sulfur‐Substituted Quaternary Carbon Atoms by Oxothiolation/Cyclization of Ynamides

Synthesis and theoretical activity evaluation of a new steroid-oxazolone derivative against COX1-1 and COX-2

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