“…Synthesis of amidoalkyl naphthols can be carried out by the multi-component condensation of aldehydes, 2-naphthols and amide/urea in the presence of Lewis or Bronsted acid catalysts such as chlorosulphonic acid [11], p-toluene sulphonic acid [12], NaHSO 4 .H 2 O [13], Fe(HSO 4 ) 3 [14], Sr(OTf) 2 [15], Iodine [16], hetropoly acid K5CoW12O40.3H 2 O [17], and hetropoly acid catalysts like cation-exchange resins [18], silica supported perchloric acid [19,20], FeCl 3 .SiO 2 [21], montmorillonite K10 clay [22], silica sulfuric acid [23], sulfamic acid [24,25], N,N,N',N'-tetrabromobenzene-1,3-disulfonamide [26]. Moreover, very recently P 2 O 5 /SiO 2 [27] magnetic nanoparticle-supported sulfuric acid [28] and MCM-41-N-propylsulfamic acid [29] has been used to carry out the synthesis.…”