Double C–S bond formation via C–H bond functionalization: synthesis of benzothiazoles and naphtho[2,1-d]thiazoles from N-substituted arylamines and elemental sulfur

Abstract

A novel, atom economic, and environmentally friendly method for the synthesis of 2-substituted benzothiazoles and 2-substituted naphtho[2,1-d]thiazoles from N-substituted arylamines and elemental sulfur has been developed under metal-free conditions. The reaction underwent the process of double C-S bond formation through C-H bond functionalization.

An Insight on the Electrocatalytic Mechanistic Study of Pristine Ni MOF (BTC) in Alkaline Medium for Enhanced OER and UOR

“…Meanwhile, in the presence of urea, catalytic current rose around 1.3 V vs. RHE as a result of UOR by Ni(OH) 2 /NiOOH redox, which was similar to OER and the previous reports. [24,25,27,29] Notably, onset potential Ni MOF for UOR was found to be at 1.34 V vs. RHE; which was closer to recent reports of NiFe LDH and Ni NP by Gao et al, b Ni(OH) 2 and Ni/Ni(OH) 2 by Singh et al, MOF-Templated Ni/C by Wang et al and higher than that of Ni MOF (BDC) by Zhu et al [27,30,42,43] On the other hand, high catalytic current density (63.15 mA cm À2 at 1.5 V vs. RHE) of Ni MOF compared to NiO WCP (8.32 mA cm À2 at 1.5 V vs. RHE) and NiO SA (30.47 mA cm À2 at 1.5 V vs. RHE) in the UOR indicates the high catalytic activity of Ni MOF towards UOR and it is found to be similar to OER catalytic activity of the present study.…”

“…[41,42] Recently, Zhu et al studied Ni MOF (BDC) for UE in alkaline medium over glassy carbon (GC) and Ni foam substrate. [43] Hu et al demonstrated Ni MOF ((4,4'-bipy)(H 3 BTC); H 3 BTC = 1,3,5-Benzenetricarboxylic acid) as cathode catalyst for oxygen reduction and oxygen evolution reaction in Li-O 2 air battery. [44] Qin et al investigated Polymolybdate based MOF for HER (1,3,5-Benzene tricarboxylate) on GC substrate.…”

Recent Advances in the Synthesis of Heterocycles via Reactions Involving Elemental Sulfur

“…While the reactivity was found to be only slight influenced by the nature of the substituents on aromatic aldehydes, the success of the reaction depended strongly on the nature of aromatic amine substrates 220 and 221. As in the previous case, [92] 2naphthylamine 220 was proven to be more reactive than anilines 221 and its reactions could proceed at 140°C. In cases of anilines 221, despite the presence of multiple electron donating groups such as alkyl, alkoxy, their reactivity remained lower than that of 2napthylamine 220.…”

“…In 2017, a synthesis of 2-substituted naphtho[2,1-d]thiazoles 217 via heating of the corresponding N-substituted 2-naphthylamines 215 with elemental sulfur at 140°C was reported (Scheme 72). [92] The reaction could proceed via the oxidation of the N-methylene group into the corresponding imine 216. Substrates bearing a substituent R that is aromatic, heteroaromatic, styryl, ester or benzoyl are competent substrates.…”

Elemental Sulfur‐Promoted [2+3+1] Annulation for Synthesis of Functionalized Thiochromeno[2,3‐b]indoles from Indole Derivatives

“…And it has been recognized as a powerful strategy by harnessing elemental sulfur as the sulfur source to construct S-containing compounds. [8][9][10][11][12] Inspired by considerable efforts in the preparation of S-containing compounds, [13][14][15][16][17][18] we envisioned the possibility of elemental sulfur incorporated indole and 2bromobenzylaldehyde to produce the desired thiochromeno [2,3-b]indole. Recently, we found that elemental sulfur could accelerate the reactivity of the 3-position of indoles.…”