New Advances in Chemical Research in 2021. In homogeneous catalysis, the catalyst is in the same phase as the reactant. The number of collisions between reactants and catalyst is at a maximum.In a patent, 15804-19-0, name is Quinoxaline-2,3(1H,4H)-dione, introducing its new discovery. Formula: C8H6N2O2
Cyclization of 2-amino-6-bromo-4-oxochromene-3-carboxamide (5) with diethyl oxalate-sodium ethoxide gave the benzopyrano<2,3-d>pyrimidine-4,6-dione (6).Ethyl 3-amino-2-carbamoyl-4-oxochromene-6-carboxylate (10a) in a similar reaction gave derivatives of a novel ring system benzopyrano<3,2-d>pyrimidine (8) but when 3-amino-4-oxochromene-2-carboxamide (10b) was subjected to the same reaction, the novel ring system benzopyrano<3,2-e>-1,4-diazepine (14a) was obtained in high yield.This structure, which contains the hitherto unknown 1,4-diazepine-2,3,5-trione ring, is supported by spectroscopic and chemical evidence.The presence of a 3-amino and a 2-carbonyl group in a chromone has an unexpected shielding effect on the chemical shift of C-8.The course of the cyclization was studied.Attempts to cyclize 3-aminomethyl-4-oxochromene-2-carboxamide (28; X= Y= H), a homologue of (10b), failed but a new ring system (31) was obtained when ethyl 3-bromo-4-oxochromene-2-carboxylate (29; R1= OEt) reacted with o-phenylenediamine.
I hope this article can help some friends in scientific research. I am very proud of our efforts over the past few months and hope to 15804-19-0, help many people in the next few years.Formula: C8H6N2O2
Reference：
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N295 | ChemSpider