Ultrasound-mediated radical cascade reactions: Fast synthesis of functionalized indolines from 2-(((N-aryl)amino)methyl)acrylates

Author(s)

Hornink, Milene M. ^[1] ; Nascimento, Vinicius R. ^[1] ; Couto, Julia L. ^[1] ; Santos, Caroline S. ^[1] ; Andrade, Leandro H. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim, Av Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: ULTRASONICS SONOCHEMISTRY; v. 79, NOV 2021.
• Web of Science Citations: 0

Abstract

Novel functionalized indolines were synthesized from 2-(((N-aryl)amino)methyl)acrylates and formamides under ultrasonic irradiation for the first time. Aiming to develop a straightforward and easy-to-implement methodology for the synthesis of indolines, an instrumentation setup was designed, including ultrasound (US) equipment (Ultrasonic Horn; tip diameter of 12.7 mm, 20 kHz, maximum power of 400 W), an open reaction flask, and an inexpensive and green catalyst (1 mol%; FeSO4 center dot 7H(2)O; CAS: 7782-63-0) without the need for anhydrous conditions. The use of the sono-Fenton process in the presence of formamides and 2-(((N-aryl)amino)methyl)acrylates afforded a broad range of functionalized indolines within 60 s in high yields. Several experimental parameters of the ultrasound-assisted reaction were evaluated, such as amplitude (40-80%), sonication time (15-60 s), and pulsed ultrasonic irradiation. A 60 s silent reaction did not produce the desired indoline. The optimized conditions for US-mediated reactions allowed the production of functionalized indolines in high isolated yields (up to 99%, 60 s reaction, pulse ration 1 s:1 s, US amplitude 60 %). (AU)

• FAPESP's process: 18/07152-4 - Application of vanadium-dependent haloperoxidase in a continuous flow system aiming selective reactions
• Grantee: Milene Macedo Hornink
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 14/50316-7 - Dimensions US-Biota São Paulo: Chemically mediated multi-trophic interaction diversity across tropical gradients
• Grantee: Massuo Jorge Kato
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 19/10762-1 - Development of a synthetic platform using carbamoyl radicals: application of the formamide in the synthesis of heterocyclic compounds
• Grantee: Leandro Helgueira de Andrade
• Support Opportunities: Regular Research Grants