Fluorinated heterocyclic compounds: an assay on the photochemistry of some fluorinated 1-oxa-2-azoles: an expedient route to fluorinated heterocycles

Buscemi, Silvestre; Pace, Andrea; Pibiri, Ivana; Vivona, Nicolò; Caronna, Tullio

doi:10.1016/j.jfluchem.2003.07.006

Cited by 37 publications

(16 citation statements)

References 46 publications

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“…A moderate yield of 5-amino-3-alkyl-1,2,4-oxadiazoles 681 was also obtained, as a rearrangement product (Scheme 13.217) [537].…”

Section: -95%mentioning

confidence: 99%

“…Similarly, the irradiation of 3-(o-aminophenyl)-1,2,4-oxadiazole 328 affords the indazole 331 from the photolytic species 329 and the benzimidazole 332 as a byproduct originating from the carbodiimide 330, the rearrangement product of 329 (Scheme 13.120) [274]. UV irradiation of 1,2,4-oxadiazoles 333 in the presence of nucleophilic nitrogen sources (primary amines, ammonia, hydrazine) affords triazoles 335, via cleavage of the NÀO bond and addition of the nucleophile to the intermediate 334 (Scheme 13.121) [275].…”

Section: Thermal and Photochemical Ring Cleavagementioning

confidence: 99%

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Oxadiazoles

Romeo¹,

Chiacchio²

2011

Modern Heterocyclic Chemistry

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“…A moderate yield of 5-amino-3-alkyl-1,2,4-oxadiazoles 681 was also obtained, as a rearrangement product (Scheme 13.217) [537].…”

Section: -95%mentioning

confidence: 99%

Section: Thermal and Photochemical Ring Cleavagementioning

confidence: 99%

Oxadiazoles

Romeo¹,

Chiacchio²

2011

Modern Heterocyclic Chemistry

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“…This photochemical approach to 2-amino-1,3,4-oxadiazoles is more significantly applied to the synthesis of perfluoroalkylated derivatives. For instance, 2-amino-5-perfluoroalkyl-1,3,4-oxadiazoles 110 can be obtained by irradiating the corresponding 5-perfluoroalkyl-1,2,4-oxadiazoles 109 (R ¼ H) at 313 nm in methanol containing a 10-fold excess of triethylamine (Scheme 12.30) [69]. In this photoreaction, additional products (12-22%) were the 5-amino-3-perfluoroalkyl oxadiazoles 111 formed by a competing ICI route.…”

Section: Oxadiazolesmentioning

confidence: 99%

Synthesis of Heteroaromatics via Rearrangement Reactions

Vivona

Buscemi

Pibiri

et al. 2009

Handbook of Synthetic Photochemistry

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The varied family of heteroaromatics contains a large fraction of organic compounds, many of which have found important applications in different fields. Many synthetic methodologies have been developed to obtain target systems and, among them, photochemical methods represent valid and elegant alternatives when the final targets are difficult to obtain through ground-state chemistry. In this chapter, we describe the photochemical synthesis of heteroaromatic compounds through rearrangement reactions, particularly via ring-transformations of heterocyclic precursors [1][2][3][4][5][6][7].A classification of all photoinduced heterocyclic ring-transformation reactions is quite difficult to achieve due to the large variety of mechanistic pathways, experimental conditions and affecting parameters. In some cases, the photochemical product and the starting substrate have the same heterocyclic nucleus. In this chapter, we will refer to such reactions, characterized by the identity of the starting and final ring, as ring-degenerate rearrangements.In general, photoinduced rearrangements of heterocycles leading to heteroaromatic compounds may involve ring-contraction, internal cyclization, ring-expansion, ring-opening or ring-closure, and ring-fragmentation processes. As for five-membered rings, two processes will be repeatedly quoted throughout this chapter:. The ring contraction-ring expansion route (RCRE), which explains the formal interchange between two adjacent ring-atoms. This results from the photoinduced cleavage of the weakest bond in the ring with formation of a three-membered ring intermediate. The latter is then converted, either thermally or photochemically, into the final five-membered heterocyclic product (see e.g., Scheme 12.22). . The internal cyclization-isomerization route (ICI), which involves the formation of a bicyclic species featuring a single bond between the ring-atoms in the 2-and 5-positions of the original heterocycle. Sigmatropic shifts then occur, leading to different bicyclic intermediates from which the final products will arise (see e.g., Scheme 12.2).Handbook of Synthetic Photochemistry. Edited

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“…In the market, there are many drugs such as thiazole, thiophene, and pyridine derivatives. For such excessive benefits, these compounds were used in many efficient synthetic transformations and are used as intermediates in many chemical reactions . It has been reported that many thiazole, thiophene, and pyrazole derivatives showed potent analgesic, anticonvulsant, anti‐inflammatory and antibacterial, antipyretics, antitumor, antiparasitic, antimicrobial, antihistaminic, antianexiety test in mice, antiarrhythmic, and serotonin antagonist .…”

Section: Introductionmentioning

confidence: 99%

Uses of ethyl benzoylacetate for the synthesis of thiophene, thiazole, pyridine, and pyran derivatives with antitumor activities

Mohareb

Mostafa

2020

Journal of Heterocyclic Chem

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The reaction of ethyl benzoylacetate with malononitrile in an oil bath at 120°C gave the condensation product 3. The latter compound underwent a series of heterocyclization to give thiophene, thiazole, pyridine, and pyran derivatives. The structures of the synthesized products were established on the basis of analytical and spectral data. The antitumor evaluation of the newly synthesized products against the six cancer cell lines namely human gastric cancer (NUGC and HR), human colon cancer (DLD1), human liver cancer (HA22T and HEPG2), human breast cancer (MCF), nasopharyngeal carcinoma (HONE1), and normal fibroblast cells (WI38) indicated that many compounds expressed high inhibition against the six cancer cell lines. Compounds 3, 8a, 8c, 14b, 16b, 16c, 16d, 19a, 19b, 20a, 22a, 27b, and 28a were the most cytotoxic compounds among the tested compounds.

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Fluorinated heterocyclic compounds: an assay on the photochemistry of some fluorinated 1-oxa-2-azoles: an expedient route to fluorinated heterocycles

Cited by 37 publications

References 46 publications

Oxadiazoles

Oxadiazoles

Synthesis of Heteroaromatics via Rearrangement Reactions

Uses of ethyl benzoylacetate for the synthesis of thiophene, thiazole, pyridine, and pyran derivatives with antitumor activities

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