An Efficient Solvent-Free Synthesis of Naphthopyranopyrimidines Using Heteropolyacid as an Ecofriendly Catalyst

MWCNTs@NHBut/PTA: New efficient solid acid catalyst for solvent free synthesis of benzochromenopyrimidines

“…Heteropolyacids possess strong Lewis acidity, structural flexibility and fairly high thermal stability and can stabilize cationic organic intermediates. In particular, 12‐tungstophosphoric acid (H 3 PW 12 O 40 ) with Keggin structure have the highest acid strength and thermal stability …”

“…Some of catalysts were used for the synthesis of benzochromenopyrimidines and related compounds in various conditions such as H 3 PO 4 /Al 2 O 3, Indium (III) chloride, ZrOCl 2 /nano‐TiO 2, P 2 O 5, I 2, Cellulose sulfuric acid, Al(H 2 PO 4 ) 3, Heteropolyacid, SiO 2 @HClO 4, Nano‐ZnAl 2 O 4, Keplerate‐type giant nanoporous isopolyoxomolybdate, Nano Zirconia Sulfuric Acid and Cerium (IV) Sulfate Tetrahydrate…”

Immobilization of Lewis acidic ionic liquid on perlite nanoparticle surfaces as a highly efficient solid acid catalyst for the solvent-free synthesis of xanthene derivatives

“…On the other hand, fused pyran ring systems especially pyranopyrimidines have biological activities including antimicrobial, 6 anticonvulsant, 7 antiplatelet, 8 antibacterial, 9 antiphlogistic, 10 analgesic, 11 anti-inammatory, 11 antigenotoxic 12 and antifungal activities. 7,[13][14][15] These unique properties, led to intensive research on the synthesis of xanthene and naphthopyranopyrimidine derivatives in the presence of various catalysts such as CoPy 2 Cl 2 , 16 I 2 , 17 choline chloride, 18 Y(NO 3 ) 3 $6H 2 O and SnCl 2 $2H 2 O, 19 ZnO NPs, 20 Al(HSO 4 ) 3 , 21 sulfamic acid, 22 perlite-SO 3 H, 23 LiBr, 24 silica sulfuric acid, 25 (nBu) 4 NBr, 26 TfOH, 27 cellulose sulfamic acid, 28 molecular iodine, 29 heteropolyacid, 30 phosphoric acid supported on alumina, 31 [IMPS][TfO], 32 [HNMP][HSO 4 ], 33 [TEBSA] [HSO 4 ], 34 [MIMPS][HSO 4 ], 35 [DMEA][HSO 4 ], 36 [BDMAP][OH] 37 and sulfonyl-functionalized acidic ionic liquids. 38 In recent years, the application of supported catalysts was developed for the synthesis of organic compounds.…”

Al(H2PO4)3 as an efficient and recyclable catalyst for the one-pot synthesis of naphthopyranopyrimidines

“…1). 19,20 Owing to the wide applications and signicance of naphthopyranopyrimidine derivatives, there is still the need to develop an efficient and environmentally benign methodology for the synthesis of these important compounds. 18 Literature reveals only a few protocols to synthesis of naphthopyranopyrimidines from the reaction of b-naphthol, aldehydes and 6-amino-1,3-dimethyl uracil catalyzed by InCl 3 and heteropolyacid.…”

“…18 Literature reveals only a few protocols to synthesis of naphthopyranopyrimidines from the reaction of b-naphthol, aldehydes and 6-amino-1,3-dimethyl uracil catalyzed by InCl 3 and heteropolyacid. 19,20 Owing to the wide applications and signicance of naphthopyranopyrimidine derivatives, there is still the need to develop an efficient and environmentally benign methodology for the synthesis of these important compounds.…”