Poly(vinylpyrrolidonium) perchlorate catalyzed one-pot synthesis of tricyclic dihydropyrimidine derivatives

1,4‐Piperazinium Hydrogen Sulfate {[H‐pi]HSO4} a Novel Di‐Cationic Ionic Liquid: Synthesis, Characterization and Its Applications as a Catalyst in Various Organic Transformations

“…In addition, this study found that this reaction conditions was suitable for the synthesis of triazolo[4,3-a]pyrimidine derivatives using 3amino [1,2,4]triazole instead of 2-aminobenzimidazole. Using this method, various products were produced with high yields ( Table 2, entries [13][14][15][16][17][18][19][20][21][22].…”

“…The versatility of these compounds led to exploit various methods for the synthesis of them in which three‐component reaction of aldehydes, malononitrile and 2‐aminobenzimidazole and/or 3‐amino[1,2,4]triazole as amine sources, is a short‐route and time‐saving method. For this purpose, a variety of catalysts and conditions have been reported …”

“…For this purpose, a variety of catalysts and conditions have been reported. [17][18][19][20][21][22][23][24][25][26] Xanthenes and their derivatives are important compounds which have attracted a lot of attentions. This importance can be attributed to their pharmaceutical and biological activities, [27][28][29][30] applications in laser technology, [31] use as fluorescent material for visualization of biomolecules, [32] and also as dyes.…”

Aminoazole-Based Diversity-Oriented Synthesis of Heterocycles

“…Dihydropyrimidine systems 102a–e (Figure 8 ) were also formed in condensation of acetoacetic acid and its derivatives (or acetylacetone) 98 with 2-aminobenzimidazole ( 101a ) [under neat conditions-ionic liquid catalyzed, US, 50°C (Reddy et al, 2016 ) etc. (Ryabukhin et al, 2011 ; Shaterian et al, 2014 ; Kaur N. et al, 2015 ; Abedini et al, 2016 ; Dam et al, 2016 )], 2-aminoimidazoles 101b [DMF-(CH 3 ) 3 SiCl, US, r.t. (Ryabukhin et al, 2011 )], 2-aminobenzothiazole ( 101c ) (MeOH-HCl, Δ (Chikhale et al, 2015 ) etc. (Zhao et al, 2013 ; Atar et al, 2014 ; Shaterian et al, 2014 ; Moradi et al, 2015 ), 2-aminothiazole 101d [HOAc, MW, 80°C (Zhao et al, 2013 ) etc.…”

“…Formation of pyrimidines 105a and 106d,e was also observed in the reactions with the CH-acids 103 : malononitrile ( 103a ) (X = CN) or ethyl 2-cyanoacetate ( 103b ) (X = COOC 2 H 5 ). The condensation of aldehydes 1 , malononitrile ( 103a ) and 2-aminobenzimidazole ( 101a ) under the variety of conditions [neat, poly(vinylpyrrolidonium) perchlorate catalyzed, 100°C (Abedini et al, 2016 ); neat- p -TSA(10%), 80°C (Reddy et al, 2014b ); EtOH-Fe 3 O 4 @IM, Δ (Hemmati et al, 2016 ); PEG-H 2 O (4:1), Δ (Survase et al, 2017 )] afforded dihydrobenzo[4,5]imidazo[1,2- a ]pyrimidines 105a . When 2-aminothiazoles 101d and 2-amino-1,3,4-thiadiazoles 101e reacted with aldehydes 1 and malononitrile ( 103a ) or ethyl 2-cyanoacetate ( 103b ), [EtOH-H 2 O, MW, 100°C (Sahi and Paul, 2016 )] pyrimidines 106d,e were isolated (Figure 9 ).…”