C−H Hydroxylation of Quinoxalin‐2(1H)‐ones through ipso‐Substitution Using tert‐Butyl Nitrite

Abstract

A convenient one‐pot synthesis of quinoxaline‐2,3‐dione has been achieved by C−H hydroxylation of quinoxalin‐2(1H)‐one using TBN (tert‐butyl nitrite) as a promoter of the reaction in DMSO. First radical‐mediated nitration using TBN at C‐3 of quinoxalin‐2(1H)‐one and followed by hydroxylation with water via ipso‐substitution led to the quinoxaline‐2,3‐dione.

Visible-Light-Induced Recyclable g-C3N4 Catalyzed C–H Hydroxylation of Quinoxalin-2(1H)-ones

“…Further optimization found that increasing the loading of g-C3N4 from 10mg to 15mg (entry 8 vs entry 12), no improved yield of 3a was observed while decreasing the loading of g-C3N4 to 5 mg gave slightly lower yield (entry 8 vs entry 13). The amount of thiols was also affective to the yield (entries [14][15]. Decreasing 2b to 1.5 equiv.…”

“…Very recently, P. Mal and coworkers reported a TBN (tert-butyl nitrite) promoted one pot hydroxylation of quinoxalin-2(1H)-ones via the nitration at C3poisition, followed by ipso-substitution with water (Scheme 1b). 14 This novel method has the disadvantage of high temperature (100 o C) and the use of toxic nitrating reagent.…”

Ionic liquid-catalysed regioselective oxygenation of quinoxalin-2(1H)-ones under visible-light conditions

“…11 In particular, metal complexes of functionalized quinoxalin-2(1 H )-one are known to exhibit antitumor, anticancer, insecticidal, anti-parasitic, antidiabetic and anticonvulsant activities. 12 A few reports on the direct C–H oxygenation of quinoxalin-2(1 H )-ones are available to date, which include; (i) graphitic carbon nitride (g-C 3 N 4 ) 13 and 9-mesityl-10-methylacridinium perchlorate as photocatalysts with blue LEDs, 14 (ii) through ipso -substitution using tert -butyl nitrite, 15 and (iii) oxidative hydroxylation with ammonium persulphate as an oxidant. 16 In addition, direct synthesis of hydroxylated quinoxalin-2(1 H )-ones from o -phenylene diamines and oxalyl chloride or ethyl chloroacetate was also reported.…”