A β-ketoenamine-linked covalent organic framework as a heterogeneous photocatalyst for the synthesis of 2-arylbenzothiazoles by cyclization reaction

Liu, Ziqi; Chen, Zhicheng; Tong, Huixin; Ji, Mengmeng; Chu, W. K.

doi:10.1039/d3gc00721a

“…19,20 The classical reported procedures for the synthesis of benzothiazole involve the condensation of 2-aminothiophenol with substituted aldehydes, 21,22 carboxylic acids 23 or nitriles. 24,25 Benzothiazoles are also obtained by the cyclization of thiobenzanilides 26–30 or 2-halothioformanilides. 31–34 Additionally, elemental sulphur can be used as a chalcogenide source in trimolecular approaches to obtain benzothiazoles by a copper-catalyzed 35,36 or by a copper-free method (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Metal- and base-free, aerobic photoredox catalysis with riboflavin to synthesize 2-substituted benzothiazoles

Heredia,

Argüello,

Schmidt

2024

Org. Biomol. Chem.

0

View full text Add to dashboard Cite

show abstract

Microwave Assisted Fast Synthesis of a Donor‐Acceptor COF Towards Photooxidative Amidation Catalysis

Dey,

Chakraborty,

Singh

et al. 2024

Angewandte Chemie

0

View full text Add to dashboard Cite

The synthesis of covalent organic frameworks (COFs) at bulk scale require robust, straightforward, and cost‐effective techniques. However, the traditional solvothermal synthetic methods of COFs suffer low scalability as well as requirement of sensitive reaction environment and multiday reaction time (2‐10 days) which greatly restricts their practical application. Here, we report microwave assisted rapid and optimized synthesis of a donor‐acceptor (D−A) based highly crystalline COF, TzPm‐COF in second (10 sec) to minute (10 min) time scale. With the increasing of the time from seconds to minutes crystallinity, porosity and morphological changes are also observed for TzPm‐COF. Owing to visible range light absorption, suitable band alignment, and low exciton binding energy (Eb=64.6 meV), TzPm‐COF can efficaciously produce superoxide radical anion (O2•−) after activating molecular oxygen (O2) which eventually drives aerobic photooxidative amidation reaction with high recyclability. This photocatalytic approach works well with a variety of substituted aromatic aldehydes having electron‐withdrawing or donating groups and cyclic, acyclic, primary or secondary amines with moderate to high yield. Furthermore, catalytic mechanism was established by monitoring the real‐time reaction progress through in‐situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study.

show abstract

Microwave Assisted Fast Synthesis of a Donor‐Acceptor COF Towards Photooxidative Amidation Catalysis

Dey,

Chakraborty,

Singh

et al. 2024

Angew Chem Int Ed

0

View full text Add to dashboard Cite

The synthesis of covalent organic frameworks (COFs) at bulk scale require robust, straightforward, and cost‐effective techniques. However, the traditional solvothermal synthetic methods of COFs suffer low scalability as well as requirement of sensitive reaction environment and multiday reaction time (2‐10 days) which greatly restricts their practical application. Here, we report microwave assisted rapid and optimized synthesis of a donor‐acceptor (D−A) based highly crystalline COF, TzPm‐COF in second (10 sec) to minute (10 min) time scale. With the increasing of the time from seconds to minutes crystallinity, porosity and morphological changes are also observed for TzPm‐COF. Owing to visible range light absorption, suitable band alignment, and low exciton binding energy (Eb=64.6 meV), TzPm‐COF can efficaciously produce superoxide radical anion (O2•−) after activating molecular oxygen (O2) which eventually drives aerobic photooxidative amidation reaction with high recyclability. This photocatalytic approach works well with a variety of substituted aromatic aldehydes having electron‐withdrawing or donating groups and cyclic, acyclic, primary or secondary amines with moderate to high yield. Furthermore, catalytic mechanism was established by monitoring the real‐time reaction progress through in‐situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study.

show abstract

A β-ketoenamine-linked covalent organic framework as a heterogeneous photocatalyst for the synthesis of 2-arylbenzothiazoles by cyclization reaction

Abstract: A series of 2-arylbenzothiazoles and their derivatives were prepared in high yields by visible light-induced intramolecular cyclization under mild conditions using TAPT-TP-COF as a photocatalyst.

Cited by 8 publications

References 65 publications

Metal- and base-free, aerobic photoredox catalysis with riboflavin to synthesize 2-substituted benzothiazoles

Metal- and base-free, aerobic photoredox catalysis with riboflavin to synthesize 2-substituted benzothiazoles

Microwave Assisted Fast Synthesis of a Donor‐Acceptor COF Towards Photooxidative Amidation Catalysis

Microwave Assisted Fast Synthesis of a Donor‐Acceptor COF Towards Photooxidative Amidation Catalysis

Contact Info

Product

Resources

About