Highly selective substitutions in 2,3-dichloropyrazine. A novel general approach to aloisines

Chekmarev, Dmitriy S.; Shorshnev, S. V.; Stepanov, A. E.; Kasatkin, Alexander N.

doi:10.1016/j.tet.2006.08.018

Cited by 15 publications

(6 citation statements)

References 32 publications

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“…It should be noted that the developed methodology is not limited to the synthesis of fluorinated benzo[ b ]furans. Replacement of perfluorobenzene with other systems capable of S N Ar, such as 2,3‐dichloropyrazines ( 22 , 24 ), enables conversion of ketones to furo[2,3‐ b ]pyrazines (Scheme 4), heteroaromatic systems known for their biological activity [46–48] . To the best of our knowledge, methods describing direct conversion of carbonyl compounds to the corresponding furo[2,3‐ b ]pyrazines, utilizing NaNH 2 [49] or KCN [50] as the ionization agent, lead to furan‐fused system with yields of just 2 %–8 %.…”

Section: Resultsmentioning

confidence: 99%

Conversion of Ketones into Blue‐Emitting Electron‐Deficient Benzofurans

Górski

Ostojić

Banasiewicz

et al. 2023

Chemistry A European J

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A novel heavy metal-free and safe synthetic methodology enabling one-step conversion of ketones into corresponding 4,5,6,7-tetrafluorobenzofurans (F 4 BFs) has been developed. The presented approach has numerous advantageous qualities, including utilization of readily available substrates, broad scope, scalability, and good reaction yields. Importantly, some of the benzofurans prepared by this method were heretofore inaccessible by any other known transformation. Importantly, furo[2,3-b]pyrazines and heretofore unexplored difuro[2,3-c:3',2'-e]pyridazine can be prepared using this strategy. Spectroscopic studies reveal that for simple systems, absorption and fluorescence maxima fall within the UV spectral range, while π-electron system expansion red-shifts both spectra. Moreover, the good fluorescence quantum yields observed in solution, up to 96 %, are also maintained in the solid state. Experimental results are supported by density functional theory (DFT) calculations. The presented methodology, combined with the spectroscopic characteristics, suggest the possibility of using F 4 BFs in the optoelectronic industry (i. e., organic light emitting devices (OLED), organic field-effect transistors (OFET), organic photovoltaics (OPV)) as inexpensive and readily available emissive or semiconductor materials.

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Section: Resultsmentioning

confidence: 99%

Conversion of Ketones into Blue‐Emitting Electron‐Deficient Benzofurans

Górski

Ostojić

Banasiewicz

et al. 2023

Chemistry A European J

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“…This reaction is commonly used on N-heterocycles employing strong bases (n-BuLi, LDA or LiHMDS, NaHMDS or KHMDS). 222,223 Scheme 45 includes examples for the reaction of pyrimidine, 224 pyridines, 223,225 and thiazolopyridine. 226 For highly electron-deficient systems, the displacement of unconventional leaving groups is also observed (Scheme 45).…”

Section: Nucleophilic Aromatic Substitutionmentioning

confidence: 99%

“…Nucleophilic aromatic substitution with acetonitrile (Chekmarev et al 2006; 224 Fier et al 2013; 223 Nishigaya et al 2014; 225…”

Section: Scheme 45mentioning

confidence: 99%

Acetonitrile as a Building Block and Reactant

Hoff

2018

Synthesis

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Acetonitrile is popular as a solvent for performing organic reactions, as a ligand in inorganic chemistry, as a mobile phase in chromatography, and as an electrolyte solvent in dye-sensitized solar cells. This is mainly due to its ability to dissolve both polar and nonpolar components. However, acetonitrile is also a valuable building block allowing atom-efficient transformations in synthetic organic chemistry. The aim of this review is to highlight synthetic transformations using acetonitrile, covering both classical approaches and modern strategies proceeding through radical intermediates or mediated by metal catalysis. Besides showcasing synthetic protocols useful for acetonitrile and analogues, warnings for when not to use acetonitrile as a solvent are also provided.1 Introduction2 Fundamental Reactions with Acetonitrile3 Cyanomethylation of Non-Aromatics4 The Acetonitrile Nitrogen as a Nucleophile5 The Blaise Reaction6 Synthesis of Pyridines7 Other Cyclization Reactions8 Cyanomethylation of Arenes and Heteroarenes9 Acetylation of Arenes Using Acetonitrile10 Synthesis of N-Arylacetamides11 Cyanation Using Acetonitrile as a Cyanide Source12 When To Avoid Acetonitrile as a Solvent13 Conclusion

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“…In 2004, Hopkins et al developed a palladium‐catalyzed heteroannulation process from readily accessible N‐ (3‐chloropyrazin‐2‐yl)methanesulfonamide and commercially available terminal alkynes (Scheme b) . In 2006, Kasatkin et al developed a two‐step process from 2,3‐dichloropyrazine with lithiated ketones/esters and nitriles followed by cyclization with primary amines (Scheme c) . In 2012, Keivanloo et al improved the yield of aloisines by modifying the conditions of Hopkins using the combination of Pd‐Cu in the presence of SDS surfactant in water .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Fused‐Pyrazines via Palladium‐Catalyzed Double Benzyl Isocyanide Insertion and Cross‐Dehydrogenative Coupling

et al. 2018

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Ap alladium-catalyzed cascade reaction has been realized for the synthesis of 5H-pyrrolo[2,3b]pyrazines and 5H-pyrazino[2,3-b]indoles from benzyli socyanide by choosing o-pivaloyloximes or oiodoanilines as as uitable substrate.T he key steps involveda re (i)o xidative addition of palladium throughN -O or C-Ic leavage; (ii)m igratory double isocyanide insertion;a nd (iii)c ross-dehydrogenative coupling. Notable features are good functional group tolerance as well as formation of three C-C and one C-N bonds. Scheme 2. Scope and limitations of oximes with isocyanides. Reaction conditions: 1a-v (0.5 mmol), 2a--c (1.05 mmol), Pd(PPh 3 ) 4 (5.0 mol%), DBU (1.1 mmol) and toluene( 0.5 M) were stirred at reflux for the indicated time unless otherwise noted.Y ields of isolated products reported;trace refers to no product isolation. Scheme 5. Plausible reaction mechanismfor 5H-pyrrolo[2,3-b]pyrazines.

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Highly selective substitutions in 2,3-dichloropyrazine. A novel general approach to aloisines

Cited by 15 publications

References 32 publications

Conversion of Ketones into Blue‐Emitting Electron‐Deficient Benzofurans

Conversion of Ketones into Blue‐Emitting Electron‐Deficient Benzofurans

Acetonitrile as a Building Block and Reactant

Synthesis of Fused‐Pyrazines via Palladium‐Catalyzed Double Benzyl Isocyanide Insertion and Cross‐Dehydrogenative Coupling

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