Sulphamic Acid (H₂NSO₃H)‐Catalyzed Multicomponent Reaction of β ‐Naphthol: An Expeditious Synthesis of Amidoalkyl Naphthols

Abstract

Sulphamic acid (H 2 NSO 3 H) was found to be an efficient catalyst for the multicomponent condensation reaction of β-naphthol, aromatic aldehydes and urea or amides to afford the corresponding α-amidoalkyl-β-naphthols in good yields. The remarkable features of this new procedure are high conversions, short reaction time, clean reaction profiles and simple experimental and work-up procedures.

Synthesis and Characterization of Nanocrystalline In2O3 and Its Efficacy as a Catalyst for the One Pot Synthesis of Amidoalkyl Naphthols

“…It was reported that 1-amidoalkyl-2-naphthols was prepared by multicomponent condensation of aryl aldehydes, 2-naphthol, and acetonitrile or amide in the presence of Lewis or Brønsted acid catalysts such as montmorillonite K10 clay, [17] HClO 4 -SiO 2 , [18,19] iodine, [20,21] [22] p-TSA, [23] sulfamic acid, [24,25] and cation-exchange resins. [26] The main drawback of many of these reactions is that they require high amount of catalyst and due to this, they require large amount of organic solvents which are volatile and toxic in nature.…”

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.…”

Polymer‐supported Sulphonic Acid Catalyzed Three‐component One‐pot Synthesis of α‐Amidoalkyl‐β‐naphthols

“…6 The product, α-amidomethyl-β-naphthols, can be converted into important 'drug like' α-amino-methyl-β-naphthol derivatives by amide hydrolysis. 7,8 Henceforth, several catalysts such as iodine, 9 [10][11][12] or supported acid catalysts, 7 there are few reports on polymer-supported acid catalysts for this reaction. To combine the merits of both solid acid catalyst and MCR, the three-component reaction of 2-naphthol, aromatic aldehyde and urea/amide catalyzed by the polymersupported sulphonic acid NKC-9 was explored.…”