Synthesis and Photophysical Properties of 3-Substituted-1 H-Indazoles: A Pd-Catalyzed Double C-N Bond Formation Strategy via 1,6-Conjugate Addition

Nasib Kayastha; Dhiraj Dutta; Kangkana Chutia; Babulal Das; Pranjal Gogoi

doi:10.1021/acs.joc.3c02176

Synthesis and Photophysical Properties of 3-Substituted-1 H-Indazoles: A Pd-Catalyzed Double C-N Bond Formation Strategy via 1,6-Conjugate Addition

J Org Chem. 2024 Jan 5;89(1):402-413. doi: 10.1021/acs.joc.3c02176. Epub 2023 Dec 8.

Authors

Nasib Kayastha^{1

2}, Dhiraj Dutta^{1

2}, Kangkana Chutia^{1

2}, Babulal Das³, Pranjal Gogoi^{1

2}

Affiliations

¹ Applied Organic Chemistry Group, Chemical Science and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam, India.
² Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
³ Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India.

PMID: 38064714
DOI: 10.1021/acs.joc.3c02176

Abstract

A Pd-catalyzed cascade process for the direct synthesis of 3-substituted-1H-indazole employing p-quinone methide (p-QM) and arylhydrazine through Pd-catalyzed double C-N bond formation via 1,6-conjugate addition is reported. This reaction strategy affords efficient and practical access to synthetically important diverse 3-substituted-1H-indazoles in good yields. The photophysical properties of the synthesized 3-substituted-1H-indazoles are investigated, and some of them showed very good fluorescence properties with quantum yields up to 85%. Also, the synthesized 3-substituted-1H-indazole exhibits an acid-sensitive fluorescence turn-off activity.