One‐Pot Synthesis of 2′‐Aminobenzothiazolo‐Arylmethyl‐2‐Naphthols Catalyzed by NBS under Solvent‐Free Conditions

Abstract

To develop a new facile protocol for the synthesis of 2′-aminobenzothiazolo-arylmethyl-2-naphthol derivatives, N-bromosuccinimide (NBS) was used as an efficient catalyst for the one-pot synthesis of 2′-aminobenzothiazolo-arylmethyl-2-naphthols in excellent yields from β-naphthol (1 mmol), aromatic aldehydes (1 mmol), and 2-aminobenzothiazole (1 mmol) at 60°C under solvent-free conditions.

α-Aminoazoles/azines: key reaction partners for multicomponent reactions

“…Besides these catalytic systems, some interesting and unique feature-embedded catalysts have also been reported to function as reaction promoters. Trichloroisocyanuric acid (TCCA) 248 and N-bromosuccinimide (NBS) 249 were successfully used to catalyze the three-component synthesis of 1-(benzothiazolylamino)methyl-2-naphthol derivatives 407. TCCA and NBS undergo in situ release of electrophilic species, Cl + and Br + ions, respectively, which make the condensation between 2-naphthol 406 and aldehydes 4 easier by increasing the electrophilicity of the carbonyl carbon of the aldehyde ( Scheme 136 ).…”

Synthesis of 2-Aminobenzothiazolomethyl Naphthols Using l-Valine Organocatalyst: An Efficient, Versatile and Biodegradable Catalyst

“…In literature, several methods for the synthesis of 2-aminobenzothiazolomethyl naphthols have been reported using microwave irradiations [15], graphite-supported perchloric acid (HClO 4 -C) [16], NBS [17], heteropoly acids [18], ionic liquids [19], fumaric acid [20], agar [21], citric acid [22] and sphalerite [23]. Apart from the trichloroisocyanuric acid [24], NaHSO 4 •H 2 O [25], Wells-Dawson heteropoly acid [26], multi-SO 3 H functionalized ionic liquid [27], Fe 3 O 4 @ SiO 2 -ZrCl 2 -MNPs [28], phosphate fertilizers [29], magnetic nanocatalyst [30], maltose [31], grindstone [32] and zinc oxide micelles as a recoverable and reusable catalyst [33] have also been used to catalyzed such type of reaction.…”

Convenient Approach for the Synthesis of 2-Aminobenzothiazolomethyl Naphthols Using Trisodium Citrate Dihydrate as Green Catalyst Under Microwave Irradiations

“…2-Aminobenzothiazoles are highly reactive compounds and used as reactants or reaction intermediates to synthesize a wide variety of biologically active fused heterocyclic compounds and in other organic transformations (Erian, 1993). In recent years, various procedures have been exist in literature for the synthesis of 2-aminobenzothiazolomethyl naphthol derivatives by adopting one-pot multi-component reactions (Hulme et al, 2009) (Jiang et al, 2010) (Dömling et al, 2012), like Agar (Moradi et al, 2015), Citric acid (Lashkari et al, 2016), Fe3O4@SiO2-ZrCl2-MNPs (Kamali and Shirini, 2018), Fumaric acid (Maghsoodlou et al, 2016), Graphite-supported (HClO4-C) (Lei et al, 2013), Grindstone (Mohan et al, 2015), Heteropoly acids (Javanshir et al, 2014), Ionic liquids (Yu and Guo, 2011), L-valine (Lal et al, 2020), Magnetic nanocatalyst (Lati et al, 2018), Maltose (Adrom et al, 2015), Microwave irradiations (Niralwad et al, 2011), Ionic liquid (Shaterian and Hosseinian, 2014), NaHSO4.H2O (Shaterian and Mohammadnia, 2013), NBS (Hosseinian and Shaterian, 2012), Phosphate Fertilizers (Li et al, 2013), Sodium dodecyl sulfate (Zimou et al, 2019), Sphalerite (Lal, 2015), Trichloroisocyanuric acid (Kumar et al, 2010), Wells-Dawson heteropoly acid (Yang L., 2012), Zinc oxide micelles (Ohanian et al, 2009), γ-Aminobutyric acid and collagen peptides biocatalyst (Mou et al, 2017) and heterogenous phosphate catalysts (Fardpour et al, 2018).These reported protocols produce good yields of the products in many instances (Shaabani et al, 2007). However, some of the synthetic protocols undergo with certain limitations such as use of very expensive catalysts, solvents, large amount of catalyst, low yields of products, long reaction times, tedious procedures for preparations of catalysts and tedious workup conditions.…”