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Wu ZH, Qu HT, Han BJ, Yang JX, Chang XW, Feng CT. Synthesis of pyrazino[1,2- b]indazoles via cascade cyclization of indazole aldehydes with propargylic amines. Org Biomol Chem 2024; 22:2226-2230. [PMID: 38363281 DOI: 10.1039/d4ob00051j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
An efficient intermolecular annulation of indazole aldehydes with propargylic amines has been developed for the synthesis of pyrazinoindazoles under catalyst- and additive-free conditions. This straightforward methodology was found to feature a wide substrate scope, high atom economy and environmental advantages. The bioactivity results of these new pyrazino[1,2-b]indazoles showed that some of them exhibited significant antifungal activity.
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Affiliation(s)
- Zeng-Hui Wu
- School of Pharmacy, Anhui University of Chinese Medicine, Anhui academy of Chinese medicine, Hefei, 230012, China.
| | - Heng-Tong Qu
- School of Pharmacy, Anhui University of Chinese Medicine, Anhui academy of Chinese medicine, Hefei, 230012, China.
| | - Ben-Jun Han
- School of Pharmacy, Anhui University of Chinese Medicine, Anhui academy of Chinese medicine, Hefei, 230012, China.
| | - Jia-Xin Yang
- School of Pharmacy, Anhui University of Chinese Medicine, Anhui academy of Chinese medicine, Hefei, 230012, China.
| | - Xiang-Wei Chang
- School of Pharmacy, Anhui University of Chinese Medicine, Anhui academy of Chinese medicine, Hefei, 230012, China.
- MOE-Anhui Joint Collaborative Innovation Center for Quality Improvement of Anhui Genuine Chinese Medicinal Materials, Hefei, 230012, China
| | - Cheng-Tao Feng
- School of Pharmacy, Anhui University of Chinese Medicine, Anhui academy of Chinese medicine, Hefei, 230012, China.
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Sun Q, Hüßler C, Kahle J, Mackenroth AV, Rudolph M, Krämer P, Oeser T, Hashmi ASK. Cascade Reactions of Aryl-Substituted Terminal Alkynes Involving in Situ-Generated α-Imino Gold Carbenes. Angew Chem Int Ed Engl 2023:e202313738. [PMID: 37882411 DOI: 10.1002/anie.202313738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023]
Abstract
An efficient, highly selective and divergent synthetic method to construct 2-substituted indoles and aryl-annulated carbazoles via the intermolecular generation of α-imino gold carbenes from terminal alkynes or diynes in combination with sulfilimines is disclosed. Importantly, the tandem reaction is proposed to proceed through an intermolecular gold carbene generation/C-H annulation followed by the activation of a second alkyne leading to 6-endo-dig cyclization, which is significantly different from previous dual activation or 1,6-carbene shift approaches for diyne systems. In the case of ortho-alkynylaniline as starting material, an unexpected regioselective formation of the indole moiety via the intermolecular path, instead of intramolecular hydroamination was discovered. This reactivity paved the way for a one-pot synthesis of the 11H-indolo [3,2-c] quinoline scaffold by exploiting the formed amino indole for a subsequent Pictet-Spengler reaction with aldehydes. The photophysical properties of the carbazoles indicated good violet-blue emission with quantum yields up to 40 %.
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Affiliation(s)
- Qiaoying Sun
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Christopher Hüßler
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Justin Kahle
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Alexandra V Mackenroth
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Matthias Rudolph
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Petra Krämer
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Thomas Oeser
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - A Stephen K Hashmi
- Institut für Organische Chemie, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
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