Tajik M, Shiri M, Hussain FHS, Lotfi Nosood Y, Baeiszadeh B, Amini Z, Bikas R, Pyra A. Highly regioselective and diastereoselective synthesis of novel pyrazinoindolones
via a base-mediated Ugi-
N-alkylation sequence.
RSC Adv 2023;
13:16963-16969. [PMID:
37288378 PMCID:
PMC10243185 DOI:
10.1039/d3ra02065g]
[Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/24/2023] [Indexed: 06/09/2023] Open
Abstract
An efficient base-mediated/metal-free approach has been developed for the synthesis of 1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-3-carboxamide derivatives via intramolecular indole N-H alkylation of novel bis-amide Ugi-adducts. In this protocol the Ugi reaction of (E)-cinnamaldehyde derivatives, 2-chloroaniline, indole-2-carboxylic acid and different isocyanides was designed for the preparation of bis-amides. The main highlight of this study is the practical and highly regioselective preparation of new polycyclic functionalized pyrazino derivatives. This system is facilitated by Na2CO3 mediation in DMSO and 100 °C conditions.
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