Novel 2‐Arylbenzothiazoles: Selective Chromogenic and Fluorescent Probes for the Detection of Picric Acid

Abstract

A series of 2‐arylbenzothiazoles has been designed and synthesized as chromogenic and fluorescent probes for the detection of picric acid (PA) over other nitro analytes. A straightforward condensation of a variety of aryl nitriles with 2‐aminobenzenethiol under metal‐ and base‐free conditions afforded the corresponding products in 26–98% yields. All 2‐arylbenzothiazoles could efficiently sense PA at micromolar levels. The highly sensitive compound 2‐(4‐((2‐methyl‐1H‐imidazol‐1‐yl)methyl)phenyl)benzo[d]thiazole (3c) showed 95% fluorescence quenching on addition of 1.0 eq of PA which can be attributed to hydrogen bonding and ground state charge transfer complex formation with a detection limit of 19.0 μM. The high sensitivity of 3 c for PA detection was also established by test strips experiment. The sensing mechanism was explored by 1H NMR titrations and Job's plot.

Combining Optical Properties with Flexibility in Halogen-Substituted Benzothiazole Crystals

“…and π•••π interactions, are key structural prerequisites for imparting elasticity. 10,11,29 When the crystal is pushed with a needle, these interactions can be ruptured easily and facilitate the molecules to drift away from their thermodynamic lattice position up to a short range. these weak interactions are instrumental for flexibility.…”

Chemical Probes for Human UDP‐Glucuronosyltransferases: A Comprehensive Review

“…Although many drugs and endogenous substances have been identified as probe substrates for a target UGT enzyme, the glucuronidation rates of these UGT probe substrates were routinely detected by LC‐UV or LC‐MS detectors, requiring relative long time for sample preparation and analysis. By contrast, fluorescence‐based biochemical assays have attracted great attention in biological and medical related fields, due to their inherent advantages including non‐destructive, highly sensitive, and applicable to HTS assays . Over the past decade, a wide range of fluorescence probes for serine hydrolases and other phase I metabolizing enzymes have been developed and widely used for evaluating enzyme activities and screening of enzyme modulators .…”

“…By contrast, fluorescence-based biochemical assays have attracted great attention in biological and medical related fields, due to their inherent advantages including non-destructive, highly sensitive, and applicable to HTS assays. [157][158][159][160][161][162][163][164][165][166][167][168] Over the past decade, a wide range of fluorescence probes for serine hydrolases and other phase I metabolizing enzymes have been developed and widely used for evaluating enzyme activities and screening of enzyme modulators. [47,48,50,51,[169][170][171][172][173] However, the design and development of fluorescence probes for UGTs is a very difficult task, due to the following three reasons.…”

A Naphthalimide-Benzothiazole Conjugate as Colorimetric and Fluorescent Sensor for Selective Trinitrophenol Detection

“…NPI exhibits a rigid planar structure, with strong π-π stacking interactions and tunable optoelectronic properties. Furthermore, benzothiazoles (BTH) are also biologically important heterocycles and have been applied in various fields, such as in biological, sensing, and optoelectronic materials [42][43][44]. It is also notable that benzothaizoles in receptors could function as molecular recognition subunits [45].…”