Unexpected Tellurohalogenation of Terminal N‐Alkynyl (Alkenyl) Derivatives of 4‐Functionalized Pyrazoles

ChemistryOpen, Год журнала: 2025, Номер unknown

Опубликована: Янв. 26, 2025

Abstract The efficient synthesis of terminal N‐alkenyl and N‐alkynyl derivatives pyrazole‐4‐carboxylic acids their methyl esters as substrates for studying electrophilic heterocyclization has been reported. regiochemistry stereoselectivity the tellurium‐induced 1‐pentynyl (butynyl, butenyl) substituted under action tellurium (IV) oxide in hydrohalic acid were determined. This leads to formation tetrahydropyrazolo[1,2‐a]pyridazinium dihydropyrazolo[1,2‐a]pyrazolium intramolecular salts, confirmed by X‐ray diffraction (XRD) comprehensive spectral analysis.

Язык: Английский

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Base-Catalyzed Chemo-, Regio- and Stereoselective Addition of Quinazolinones to Trifluoromethylated Internal Alkynes for Access to N3-Vinylquinazolinones

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Май 31, 2025

A base-catalyzed addition of quinazolinones to unsymmetrical trifluoromethylated internal alkynes was accomplished for straightforward access various N3-vinylquinazolinones. Excellent chemo-, regio-, and stereoselectivity were achieved along with moderate good efficacy broad substrate scope under environmentally benign conditions. Moreover, N3-vinylquinazolinone adducts could be readily transformed into a useful fused tetracyclic scaffold via one-step intramolecular oxidative cross-coupling. On the basis preliminary control experiment results, catalytic cycle proposed clarify plausible reaction mechanism.

Язык: Английский

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Photoredox/HAT-Catalyzed Intramolecular Hydrocyclization of Alkenes toward 2,3-Fused Quinazolinones and Dihydroquinazolinones

Organic Letters, Год журнала: 2024, Номер unknown

Опубликована: Окт. 2, 2024

New photochemical approaches to 2,3-fused quinazolinones and dihydroquinazolinones are disclosed. The intramolecular hydrocyclization proceeds in moderate excellent yields across diverse alkenes with high regioselectivity diastereocontrol. Mechanistic studies indicated that the radical cascade processes involve thiophenol acting as single-electron transfer hydrogen atom reagents. success of gram-scale synthesis proves strategy can be used for practical applications.

Язык: Английский

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Chemistry in Ukraine

The Chemical Record, Год журнала: 2024, Номер 24(2)

Опубликована: Янв. 29, 2024

Abstract In this special issue, we highlight recent advances in chemical research by scientists Ukraine, as well their compatriots and collaborators outside the country. Besides spotlighting contributions, see our task fostering global partnerships multi‐, inter‐, trans‐disciplinary collaborations, including much‐needed co‐funded projects initiatives. The three decades of renewed Ukraine independence have seen rather limited integration Ukrainian (chemical) science into communities. [1] At same time, surge collaborative initiatives between European Union (EU) echoes unfolding steps towards Ukraine's full participation to Horizon Europe Program. This recently implemented step opens enormous possibilities for researchers apply diverse EU grants. Moreover, a number journal issues collections were launched chemistry (i. e., Chemistry Heterocyclic Compounds [2] ChemistrySelect [3] ). Other scientific include ‘European School Ukrainians’ [4] ‘Kharkiv Chemical Seminar’ [5] voluntary aimed at engaging international research.

Язык: Английский

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Synthesis of Indole‐Fused Pyrazino[1,2‐a]quinazolinones by Copper(I)‐Catalyzed Selective Hydroamination‐Cyclization of Alkynyl‐tethered Quinazolinones

Chemistry - A European Journal, Год журнала: 2024, Номер unknown

Опубликована: Авг. 20, 2024

We described a copper(I)-catalyzed atom economic and selective hydroamination-cyclization of alkynyl-tethered quinazolinones to prepare variety indole-fused pyrazino[1,2-a]quinazolinones in good excellent yields ranging from 39 %-99 % under mild reaction conditions. Control experiments revealed that coordination-directed method quinazolinone moiety with copper(I) was important for the alkynes at N1-atom instead N3-atom quinazolinone. The could be easily performed gram scales some prepared donating groups on indole showed distinct fluorescence emission wavelength blue shift acid

Язык: Английский

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Access to Seleno‐Functionalized Thiazolo[3,2‐a]Pyrimidinones and Pyrimido[2,1‐b][1,3]Thiazinones via Selenocyclization of 2‐Alkenylthiopyrimidinones and Their Fused Analogs

ChemistrySelect, Год журнала: 2024, Номер 9(36)

Опубликована: Сен. 19, 2024

Abstract The methodology of electrophilic selenylation/cyclization 2‐alkenylthiopyrimidinones and their fused analogs underlies most the reported synthetic approaches to seleno‐functionalized thiazolo[3,2‐ a ]pyrimidinones pyrimido[2,1‐ b ][1,3]thiazinones. We have developed novel implementation this strategy using as reagent phenylselenyl chloride or visible‐light‐induced radical‐generating (PhSe) 2 /CBr 4 system. effect unsaturated substrate structure reaction conditions on selenocyclization regioselectivity has been revealed analyzed in detail. It established that regardless used, 2‐allylthiopyrimidinones react with selenylating agents via 5‐ exo ‐ trig cyclization mainly involving N1 nitrogen atom give selenium‐containing major products. On contrary, 2‐cinnamylthiopyrimidinones is dominated by 6‐ endo mode: it mostly involves six‐membered ring closure at N3 thus leading selenylated ][1,3]thiazinones, regiochemistry governed position nature substituents pyrimidine ring. However, some cinnamylthio‐substituted substrates yield cyclized products LiClO /МеNO system (a sufficiently polar solvent strong electrolyte added).

Язык: Английский

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Manganese‐ Mediated Cascade Radical Oxidative Cyclization/1,6‐Conjugate Addition of Unsaturated Oximes with p‐Quinone methides: Facile Access to β,β‐Diarylmethine Isoxazolines

Chemistry - An Asian Journal, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 9, 2024

A simple and efficient strategy for the synthesis of structurally diverse β,β-diarylmethine substituted isoxazoline derivatives have been developed. This approach employs a manganese-promoted oxidative cyclization coupled with 1,6-conjugate addition unsaturated oximes to p-quinone methides. The key features this study include formation C-O C-C bonds through intramolecular intermolecular interactions, facilitated by in situ generated iminoxyl radicals. isoxazolines, bearing wide range functional groups, were isolated high yields.

Язык: Английский

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Proton- and iodine-induced cyclization of 2-(pent-4-en-1-yl)quinazolin-4(3H)-ones: synthesis of pyrrolo[2,1-b]quinazolinone and pyrido[1,2-a]quinazolinone derivatives

Chemistry of Heterocyclic Compounds, Год журнала: 2024, Номер unknown

Опубликована: Дек. 30, 2024

Язык: Английский

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