Silica supported perchloric acid (HClO4–SiO2): an efficient and recyclable heterogeneous catalyst for the one-pot synthesis of amidoalkyl naphthols

Citric Acid Catalyzed Synthesis of Amidoalkyl Naphthols under Solvent-free Condition: An Eco-friendly Protocol

“…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.…”

“…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. However some of the above reported methods suffer from disadvantages such as long reaction times [17], the use of expensive reagents [15], low yields of products [24,25], high catalyst loading [23], corrosive reagents [11], strongly acidic conditions [19,20] and the use of an additional microwave oven [14], or ultrasonic irradiation [23]. Therefore, to overcome these limitations, the discovery of a new, eco-friendly and easily available catalyst with high catalytic activity and short reaction time for the preparation of amidoalkyl naphthols is still desirable.…”

Design, synthesis and biological evaluation of new Mannich products using ethyl ammonium nitrate as reusable ionic liquid

“…The bradycardiac effects of these motifs have also been reported [10]. Owing to the biological and medicinal as well pharmacological importance of 1-amidoalkyl-2-naphthols derivatives, efforts have been made by the various researchers in developing multi-component coupling reactions for the synthesis of 1-amidoalkyl-2-naphthols from aldehydes, phenols and amides/ carbamates under thermal and/or heating or sonication conditions using various catalysts such as montmorillonite K10 [11], Ptsa [12], iodine [13], Fe(HSO 4 ) 3 [14] , K 5 CoW 12 O 40 ·3H 2 O [15], HClO 4 -SiO 2 [16] , cation exchange resins [17], silica sulfuric acid [18], thiamine hydrochloride [19], zwitterionic salts [20] and supported acid catalyst [21] and ionic liquids [22].…”

Efficient and solvent-free synthesis of 1-amidoalkyl-2-naphthols using N,N,N’,N’-tetrabromobenzene-1,3-disulfonamide

“…Since they are performed without the need to isolate any intermediate the process reduces the reaction time and saves both energy and raw materials [2]. Therefore, the design of novel MCRs has attracted a great deal of attention from research groups working in the field of medicinal chemistry, drug discovery, and materials science [3]. Reactions such as Biginelli [4], Ugi [5], and Manich [6] are some examples of MCRs.…”

“…In recent years, ZrOCl 2 [9] [14], VB 1 [15], P 2 O 5 [16], Yb(OTf) 3 Bmim BF 4 [17], CuPMo [18], NKC-9 [19], and H 3 Mo 12 O 40 P [20] have been utilized, as catalysts, for this synthesis. In continuation of our interest in the application of N,N,N',N'-tetrabromobenzene-1,3-disulfonamide [TBBDA] [21] (Fig.…”