“…These compounds are also utilized as urease inhibitors 3 . A number of methods have been reported for the synthesis of these compounds in the presence of various catalysts like molecular iodine like molecular iodine 4 , tetrabutylammonium bromide (TBAB) 5 Manganous chloride (MnCl2 _ 4H2O) 6 sodium dodecyl sulfate(SDS) 7 , tetrabutylammoniumhexatungstate ([TBA]2[W6O19]) 8 , sulfated titania(TiO2/SO4) 9 , ruthenium(III) chloride hydrate (RuCl3⋅nH2O) 10 , Cobalt(II) chloride hexahydrate 11 , tungstate sulfuric acid 12 , NaHSO4.SiO2/ Indion 190 resin 13 , Fe3O4 nanoparticles 14 Nano TiO2@KSF 15 Boron Sulfonic Acid 16 . Although various procedures are reported for the synthesis of bis-(4hydroxycoumarin)methanes, disadvantages including low yields of products, long reaction times, nonrecyclable catalyst, use of an excess of reagents or catalysts, and harmful and corrosive solvents.…”