- Potassium exchanged layered zirconium phosphate as catalyst in the preparation of 4H-chromenes
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Substituted 4H-chromenes were easily prepared by reaction of salicylaldehydes and ethylcyanoacetate in solvent free conditions using potassium exchanged layered zirconium phosphate as catalyst.
- Curini, Massimo,Epifano, Francesco,Chimichi, Stefano,Montanari, Francesca,Nocchetti, Morena,Rosati, Ornelio
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- Electrochemically induced chain transformation of salicylaldehydes and alkyl cyanoacetates into substituted 4H-chromenes
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Electrolysis of salicylaldehydes and alkyl cyanoacetates in ethanol in an undivided cell in the presence of sodium bromide results in the formation of substituted alkyl 2-amino-4-(1-cyano-2-alkoxy-2-oxoethyl)-4H-chromene-3-carboxylates in 85-95% yields.
- Elinson, Michail N.,Dorofeev, Alexander S.,Feducovich, Sergey K.,Gorbunov, Sergey V.,Nasybullin, Ruslan F.,Stepanov, Nikita O.,Nikishin, Gennady I.
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- Synthesis of 2-amino-3-cyano-4H-chromen-4-ylphosphonates and 2-amino-4H-chromenes catalyzed by tetramethylguanidine
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Synthesis of 2-amino-4H-chromen-4-ylphosphonates and 2-amino-4H-chromenes has been accomplished by the reaction of salicylaldehyde, malononitrile, dialkyl/diphenylphosphites catalyzed by 1,1,3,3-tetramethylguanidine (TMG) under neat conditions at room tem
- Kalla, Reddi Mohan Naidu,Byeon, Seong Jin,Heo, Min Seon,Kim, Il
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- Electrocatalytic chain transformation of salicylaldehyde and CH acids into substituted 4H-chromenes
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Electrochemically initiated catalytic chain transformation of salicylaldehydes and CH acids containing the cyano group in an ethanolic solution in an undivided cell produced substituted 4H-chromenes in 85-95% yields.
- Feducovich,Elinson,Dorofeev,Gorbunov,Nasybullin,Stepanov,Nikishin
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- Aegle marmelos in heterocyclization: Greener, highly efficient, one-pot three-component protocol for the synthesis of highly functionalized 4 H -benzochromenes and 4 H -chromenes
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A facile, one-pot three-component protocol for the synthesis of 2-amino-4H-chromene derivatives has been demonstrated using Bael Fruit Extract (BFE) as a natural catalyst in a green reaction medium. This method offers a mild, efficient and highly economic
- Shinde, Sachin,Damate, Shashikant,Morbale, Smita,Patil, Megha,Patil, Suresh S.
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p. 7315 - 7328
(2017/02/05)
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- First report of the application of simple molecular complexes as organo-catalysts for Knoevenagel condensation
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A series of molecular complexes have been designed, synthesized and used as organo-catalysts for the first time for very efficient Knoevenagel condensation. Molecular complexes are thermally stable, easily recyclable, and have a low cost of preparation. T
- Panja, Sumit Kumar,Dwivedi, Nidhi,Saha, Satyen
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p. 65526 - 65531
(2015/08/18)
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- Applications of caged-designed proton sponges in base-catalyzed transformations Dedicated to Professor Milan Kratochvíl for his 90th birthday anniversary.
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Superbasic properties of caged proton sponges (PSs) - substituted diazatetracyclo[4.4.0.13,10.15,8]dodecanes (DTDs) - were utilized in Knoevenagel and Claisen-Schmidt condensations, the Pudovik reaction, and Michael addition. This investigation covers the influence of the solvent, reaction temperature, catalyst loadings as well as the electronic properties of substituents upon the reaction. Moreover, we provided an activity comparison between our new base and a well-known and commercially available proton sponge (DMAN). The basicity (in MeCN) of our chosen DTD (pKBH+=21.7±0.1) exceeded the prototypal PS - 1,8-bis(dimethylamino)naphthalene (DMAN, pKBH+=18.6), by three orders of magnitude. We proved that DTDs are reasonably active species in monitored reactions, which is a consequence of a hydrogen bridge angle (~130°) between the two nitrogen atoms and the captured proton. We present here syntheses of aminoindolizine, substituted 4H-chromene, and flavanones, and the unexpected formation of a bis-addition product formed after Michael addition, all under mild conditions.
- Galeta, Juraj,Potá?ek, Milan
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