Lanthanide Triflate Catalyzed Biginelli Reaction. One-Pot Synthesis of Dihydropyrimidinones under Solvent-Free Conditions

Synthesis and Antitumor Evaluation of Novel Dihydropyrimidine, Thiazolo[3,2-a]Pyrimidine and Pyrano[2,3-d]Pyrimidine Derivatives

“…In our work, the pyrimidine derivative exists in the thiol form and not in the thione form as it was reported. [25][26][27][28][29] This was confirmed through the reaction of the pyrimidine derivative 7c with a-halocarbonyl compounds. Thus, reaction of 7c with ω-bromo-4-chloroacetophenone afforded thiazolo [3,2- Condensation of each of the arylaldehydes 1a-e with the malononitrile and thiourea in ethanol in the presence of a catalytic amount of triethylamine produced 1,4-dihydromercaptopyrimidines 9a-d and chromeno [4,3-d]pyrimidine 9e (Scheme 4).…”

“…11,[20][21][22][23][24] Also, it was reported that 3,4-dihydropyrimidinone/thione have been synthesized by a three-component condensation of aldehydes, ethyl acetoacetate and urea/thiourea using different catalysts and new methods to improve and modify this reaction. [25][26][27][28][29] Moreover, the one step synthesis of 6-amino-5-cyano-4-phenyl-2-mercaptopyrimidine using aldehydes, malononitrile and urea/thiourea in the presence of a catalytic amount of phosphorus pentoxide has been reported. 30 Therefore, in the view of the facts mentioned above and to discover potentially active new agents, we have synthesized some new dihydropyrimidine derivatives by a three-component condensation (MCR) of aromatic aldehydes, thiourea and either ethyl cyanoacetate, ethyl acetoacetate or malononitrile using triethylamine under refluxing condition.…”

Reações multicomponentes de biginelli e de mannich nas aulas de química orgânica experimental: uma abordagem didática de conceitos da química verde

“…24 Entretanto, muitas transformações são lentas ou fazem uso de reagentes caros, meio fortemente ácido, grande volume de solventes ou quantidades estequiométricas de catalisadores, nem sempre disponíveis comercialmente. [25][26][27][28][29][30] De modo a contornar estes obstáculos, as metodologias a serem trabalhadas em aulas experimentais devem empregar condições brandas, tempos de reação curtos (não superiores a 4 h) e reagentes comerciais a um custo acessível, preferencialmente sem o envolvimento de solventes orgânicos em quantidades excessivas. Diversas condições reacionais descritas na literatura para a síntese das di-hidropirimidin-2-onas multissubstituídas 6a-c (Esquema 3) a partir de acetoacetato de etila (3), aldeídos aromáticos 4 e ureia (5) possuem estas características e podem ser previamente apresentadas pelo professor, [31][32][33][34][35][36][37][38][39] 4 .K 2 SO 4 ) ou ainda condições na ausência de qualquer aditivo.…”

Glutamic acid as an Efficient Catalyst for Synthesis of Dihydropyrimidinones

“…Although numerous methods are capable of affecting these synthesis has been previously reported [6][7][8][9][10][11][12][13][14][15][16] . Glutamic acid has been used previously as a catalyst for synthesis of organic compound 17 , Previously, we have synthesized a number of heterocyclic compounds [18][19][20][21][22][23][24][25][26][27] .…”