Three component, one-pot synthesis of dihydropyrano[3,2-c]chromene derivatives in the presence of H6P2W18O62· 18H2O as a green and recyclable catalyst

Microwave-Assisted Synthesis of Novel 2H-Chromene Derivatives Bearing Phenylthiazolidinones and Their Biological Activity Assessment

“…Moreover, they can also be employed as cosmetics and pigments [13] and utilized as potential biodegradable agrochemicals [15]. Some of these compounds have been already prepared in the presence of piperidine [16], diammonium hydrogen phosphate (DAHP), S-proline [17], K2CO3 under microwave irradiation [18], H6P2W18O62· 18H2O [19], MgO [20] and tetrabutylammonium bromide (TBAB) [21]. Each method has its own advantages and disadvantages.…”

Heteropoly acids-catalyzed organic reactions in water: doubly green reactions

“…The three-component synthesis of 2-amino-5-oxodihydropyrano[3,2-c]chromene derivatives was reported by condensing 4-hydroxycoumarin, aldehydes, and alkylnitriles using a catalytic amount of H 6 (35). A one-pot condensation of 2-aminobenzothiazole, 2-naphthol, and appropriate aldehydes catalyzed by HPA in an aqueous medium afforded the Mannich adduct 2′-aminobenzothiazolomethylnaphthols at 45°C under ultrasound irradiation (Scheme 27).…”

Novel ionic liquid supported on Fe3O4 nanoparticles as an efficient catalyst for the synthesis of new chromenes

“…Therefore, the improvement of simple methods for the development of chromenes is still necessary and in demand. The preparation of chromenes has been reported in the presence of diverse catalysts such as 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), [6] tetrabutylammonium bromide, [7] diammonium hydrogen phosphate, [8] H 6 P 2 W 18 O 62 ⋅18H 2 O, [9] Zn(L-proline) 2 , [10] nanomagnetically modified thioglycolic acid, [11] Fe 3 O 4 /poly(ethylene glycol) core/shell, [12] nano-MgO, [13] 1-butyl-3-methylimidazolium hydroxide, [14] 1-butyl-3-methylimidazolium tetrafluoroborate, [15,16] 1,3-dimethyl-2-oxo-1,3-bis(4-sulfobu tyl)imidazolidine-1,3-diium hydrogen sulfate, [17] 3-hydroxypropanaminium acetate [18] and N,N-dimethylaminoethylbenzyldimethylammonium chloride. [19] However, some of the reported methods have disadvantages including long reaction times, harsh reaction conditions and use of toxic and non-reusable catalysts.…”