Categories: Synthesis of N-Heterocycles > benzo-fused N-Heterocycles >
Synthesis of quinoxalinediones
Recent Literature
Whereas the cyclocondensation of 2-aminothiophenols with 1,2-biselectrophiles
such as ethyl glyoxalate and diethyl oxalate in aqueous medium leads to the
formation of benzothiazole-2-carboxylates via a 5-endo-trig process
contrary to Baldwin’s rule, the reaction of 2-aminophenols/anilines produced the
corresponding benzazine-3-ones or benzazine-2,3-diones via a 6-exo-trig
process in compliance with Baldwin’s rule.
T. M. Dhameliya, S. S. Chourasiya, E. Mishra, P. S: Hadhavar, P. V. Bharatam, A.
K. Chakraborti, J. Org. Chem.,
2017, 82, 10077-10091.
An unprecedented metal-free reaction of o-aminobenzamides with CO2
provides N-unsubstituted and N3-substituted quinazoline-2,4(1H,3H)-diones
at room temperature. This eco-friendly protocol tolerates a broad range of
functional groups (including alkyl, aryl, and heterocycle groups) at the N3-position.
L. Zhang, Q. Chen, L. Li, N. Ma, J. Tian, H. Sun, Q. Xu, Y. Yang, C. Li, Org. Lett., 2023, 25,
2471-2475.
A visible-light-promoted oxidation of quinoxalin-2(1H)-ones provides
various quinoxalinediones in very good yields under an ambient air atmosphere
using recyclable graphitic carbon nitride (g-C3N4) as a
heterogeneous photocatalyst. Importantly, the heterogeneous catalyst can be used
at least six times without significant loss of activity.
L.-Y. Xie, Q.-X. Xie, Y.-D. Chen, J.-Y. Zhou, S. Peng, Synthesis, 2023,
55,
443-450.
Visible light mediates a metal-free oxygenation of quinoxalin-2(1H)-one
to quinoxaline-2,3-diones in very good yields by employing Mes-Acr-MeClO4
as a photocatalyst without using any additive or cocatalyst. O2
serves as the eco-friendly and green oxidant source for this conversion. In
addition, this sustainable approach tolerates a broad range of functional groups.
S. Sau, P. Mal, J. Org. Chem., 2022, 87,
14565-14579.