Regioselective Anionic [3+2] Cyclizations of Isoxazole, Pyrazole and 1,2,4-Triazole Dinucleophiles − Efficient Synthesis of 2,4-Dihydroimidazo[4,5-b]quinoxalines, 3H-Imidazo[1,2-b]pyrazoles and 5H-Imidazo[2,1-c][1,2,4]triazoles

Langer, Peter; Wuckelt, Jörg; Döring, Manfred; Schreiner, Peter R.; Görls, Helmar

doi:10.1002/1099-0690(200106)2001:12<2257::aid-ejoc2257>3.0.co;2-z

Cited by 22 publications

(2 citation statements)

References 22 publications

(13 reference statements)

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“…Regioselective cyclization reaction between compound 166 and oxaldiimidoyl dichlorides 186 in THF in the presence of triethylamine afforded 3 H -imidazo[1,2- b ]pyrazoles 187 in good yields ( Scheme 93 ) [ 133 ].…”

Section: Heteroannulated Pyrazolesmentioning

confidence: 99%

Substituted Pyrazoles and Their Heteroannulated Analogs—Recent Syntheses and Biological Activities

et al. 2021

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Pyrazoles are considered privileged scaffolds in medicinal chemistry. Previous reviews have discussed the importance of pyrazoles and their biological activities; however, few have dealt with the chemistry and the biology of heteroannulated derivatives. Therefore, we focused our attention on recent topics, up until 2020, for the synthesis of pyrazoles, their heteroannulated derivatives, and their applications as biologically active moieties. Moreover, we focused on traditional procedures used in the synthesis of pyrazoles.

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Section: Heteroannulated Pyrazolesmentioning

confidence: 99%

Substituted Pyrazoles and Their Heteroannulated Analogs—Recent Syntheses and Biological Activities

et al. 2021

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“…Pyrazole derivatives are important intermediates in organic synthesis and possess a range of interesting biological and antimicrobial properties [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Their fused pyrimidine derivatives are used as dyes [ 9 , 10 , 11 , 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Some Novel Pyrazolo[1,5-a]pyrimidine Derivatives and Their Application as Disperse Dyes

et al. 2011

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A series of novel monoazo-disperse dyes containing pyrazolo[1,5-a]pyrimidine structures were synthesized starting with the coupling reaction between ethyl cyanoacetate and 4-hydroxybenzenediazonium chloride, followed by treatment of the resulting hydrazone product with hydrazine hydrate. The pyrazolohydrazone 6 is then treated with either 2,4-pentandione and enaminonitrile or aryl-substituted enaminoketones to give the target pyrazolo[1,5-a]pyrimidine dyes 7 and 15a-d. Structural assignments to the dyes were made using NMR spectroscopic methods. A new high temperature method, using microwave heating, was employed to apply these dyes to polyester fibers. Most of the dyed fabrics tested displayed moderate light fastness and excellent washing fastness properties.

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Efficient Synthesis and First Regioselective C‐3 Direct Arylation of Imidazo[1,2‐b]pyrazoles

Grosse

Pillard²,

Massip

et al. 2012

Chemistry A European J

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Highly regioselective: An efficient synthesis of the imidazo[1,2-b]pyrazole core has been developed, and the first regioselective palladium-catalyzed direct arylation of the C-3 position is described (see scheme). Good to excellent yields were obtained for a wide range of aryl partners with electron-rich and electron-poor substituents. This methodology allows rapid access to a large variety of imidazo[1,2-b]pyrazole products and could open the way to the design of new biologically active compounds.

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Regioselective Anionic [3+2] Cyclizations of Isoxazole, Pyrazole and 1,2,4-Triazole Dinucleophiles − Efficient Synthesis of 2,4-Dihydroimidazo[4,5-b]quinoxalines, 3H-Imidazo[1,2-b]pyrazoles and 5H-Imidazo[2,1-c][1,2,4]triazoles

Cited by 22 publications

References 22 publications

Substituted Pyrazoles and Their Heteroannulated Analogs—Recent Syntheses and Biological Activities

Substituted Pyrazoles and Their Heteroannulated Analogs—Recent Syntheses and Biological Activities

Synthesis of Some Novel Pyrazolo[1,5-a]pyrimidine Derivatives and Their Application as Disperse Dyes

Efficient Synthesis and First Regioselective C‐3 Direct Arylation of Imidazo[1,2‐b]pyrazoles

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