Formation of a nanorod shaped ionogel and its high catalytic activity for one-pot synthesis of benzothiazoles

Abstract

An ionogel was synthesized through the confinement of 1,3,5-trimethyl pyrazolium chloride as an ionic liquid in a silica-gel matrix through a sol-gel process, and its catalytic activity was compared with a silica supported ionic liquid for the synthesis of benzothiazoles using 2-aminothiophenol and aldehydes/ketones. The reaction between 3-methoxyacetophenone and 2-aminothiophenol produced 2-(3-methoxyphenyl)benzothiazole, and its structure was determined using X-ray crystallography. The ionogel was characterized with SEM, TEM, FTIR and TGA.

Solid‐Supported Materials‐Based Synthesis of 2‐Substituted Benzothiazoles: Recent Developments and Sanguine Future

“…Ionogel-mediated synthesis of 2-substituted benzothiazoles. [222] Scheme 40. Fe 3 O 4 @SiO 2 @Polyionene/Br 3 À mediated synthesis of 2-substituted benzothiazoles.…”

“…With the advancements in supported reagents, a new way of impregnation involves the development of ionogel which is a three‐dimensional network synthesized by mixing ionic liquid in a silica gel matrix through a sol‐gel process. Sharma and coauthors [222] reported 1,3,5‐trimethylpyrazolium chloride‐based nanorod‐shaped ionogel as a new and attractive solid support as well as a catalyst for the synthesis of benzothiazoles ( 19 ). The reaction was initially screened with different catalysts and varying solvents in order to establish the optimized reaction conditions.…”

1,3,5-Trimethylpyrazolium chloride based ionogel as an efficient and reusable heterogeneous catalyst for the synthesis of benzimidazoles

“…The preparation and characterization of ionogel has already been described. 16 The ionogel was synthesized from tetraethylorthosilicate and 1,3,5-trimethylpyrazolium through sol-gel process (scheme 1). The characterization of ionogel was done by SEM, TEM, FTIR and TGA.…”

“…In our previous study, the ionogel was shown to be highly active for the synthesis of benzothiazoles. 16 Earlier also, we reported the modification of catalyst with ionic liquid to improve the catalytic behavior of the catalyst for one-pot synthesis of 1,4-dihydropyridines. 17…”

Progress in Synthesis of 2-Substituted Benzothiazole Compounds

“…同时, 反应可扩大到克级规模, 对大规模生产具 有 很 大 的 应 用 价 值 (Scheme 3, Method 2). 2015 年 , Sharma 等 [16] 以 1,3,5-三甲基-吡唑氯化铵为离子液体 (lonogel)研制了一种离子凝胶, 用于在无溶剂条件下催 化 2-氨基苯硫酚与各种醛反应合成 2-取代苯并噻唑化 合物. 反应条件温和, 产率良好且该离子凝胶可重复使 用(Scheme 3, Method 3).…”