Convenient Approach for the One-Pot, Three-Component Synthesis of Triheterocyclic 4H-Pyrimido[2,1-b]benzothiazole Derivatives Using TBAHS

Agar: a novel, efficient, and biodegradable catalyst for the one-pot three-component and green synthesis of 2,3-dihydroquinazolin-4(1H)-one, 4H-pyrimidobenzothiazole and 2-aminobenzothiazolomethylnaphthol derivatives

“…The crude product was recrystallized from ethanol to afford the pure 4H-pyrimido [2,1-b] [1,3]benzothiazole derivatives. The desired pure products were characterized by comparison of their physical data (melting points, IR and 1 H NMR) with those of known compounds in the literature [40][41][42][43][44].…”

Fe3O4@nano-cellulose/Cu(ii): a bio-based and magnetically recoverable nano-catalyst for the synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives

“…14 Pyrimido[2,1-b]benzothiazole derivatives were synthesized through multicomponent reaction between 2-amino benzothiazole, aromatic aldehydes and b-ketoesters. [15][16][17][18] Previously, this protocol has been catalyzed by iron uoride, 19 pyridine, 11 acetic acid, 20 1,1,3,3-N,N,N 0 ,N 0 -tetramethylguanidinium tri-uoroacetate (TMGT), 16 tetrabutylammonium hydrogen sulfate (TBAHS), 17 N-sulfonic acid modied poly(styrene-maleic anhydride) (SMI-SO 3 H), 21 chitosan, 18 aluminum trichloride 22 and Fe 3 O 4 @nano-cellulose/TiCl. 23 Some of the reported protocols have harsh conditions and long reaction times.…”

Preparation, characterization and use of new lignocellulose-based bio nanocomposite as a heterogeneous catalyst for sustainable synthesis of pyrimido benzazoles

“…Polycyclic fused-ring heterocycles containing nitrogen and sulfur atom, are of great importance, especially in the pharmaceutical fields, because of their abundance in nature and their diverse biological properties (26)(27)(28). One of these important compounds, the pyrimido benzazole which is synthesized through Biginelli-like reaction (29,30), was extensively studied for their medicinal applications such as antimicrobial, antifungal, antibacterial, antihypertensive, antiviral and anticancer activities (31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42). They are also potent HIV integrase inhibitors (25,43), LTD 4 receptor antagonists (34), and are also used for the treatment of bronchial asthma and neurodegenerative disease (37,39,44).…”