Direct C(sp²)−H Amination to Synthesize Primary 3‐aminoquinoxalin‐2(1H)‐ones under Simple and Mild Conditions

Abstract

A convenient CÀH amination of quinoxalin-2-ones has been developed. This transformation provides concise access to 3-aminoquinoxalin-2(1H)-ones with a broad tolerance of functional groups, utilizing TMSN 3 as an amino source under simple and mild conditions. The target 3-aminoquinoxalin-2(1H)-ones are important intermediates for the synthesis of biologically active 3-N-substituted quinoxalin-2-one derivatives.

Visible‐Light Photoredox Catalyzed C−N Coupling of Quinoxaline‐2(1H)‐ones with Azoles without External Photosensitizer

“…The condensation reaction of 1,2-diaminobenzene with 1,2dicarbonyl and its derivatives is a typical method for the preparation of quinoxalin-2(1H)-ones, [2] and the radical cyclization is also an important complementary route to get quinoxalin-2(1H)-ones. [3] Recently, scientists devote themselves to the investigation on the direct modification of quinoxaline 2(1H)ones because it can provide more complex molecules, and a great progress has been made in the direct C3-functionalization of quinoxaline-2(1H)-ones, including arylation, [4] alkylation, [5] alkoxylation, [6] trifluoromethylation, [7] difluoroalkylation, [8] chalcogenation, [9] cyanation, [10] acylation, [11] amination, [12] amidation, [13] azidation, [14] and phosphonation. [15] However, the complex catalytic system with transition-metal-catalysts, photosensitizer, stoichiometric oxidants and additives are usually necessary in the most of the above transformations.…”

Direct Introduction of Sulfonamide Groups into Quinoxalin‐2(1H)‐ones by Cu‐Catalyzed C3‐H Functionalization

“…or N,Nbidentate ligands (1,10-phen • H 2 O, 2,2'-Bipyridine, etc.) were further examined under the selected reaction conditions exhibited in the entry 12, but did not lead to any improvement (Table 1, entries [17][18][19][20]. In conclusion, optimized reaction conditions involved the use of 1 a (0.3 mmol), 2.0 equivalents of sulfonamide 2 a, 10 mol% of Cu(PF 6 ) • 4CH 3 CN catalyst, 2.0 equivalents of (NH 4 ) 2 S 2 O 8 , and stirring in CH 3 CN (3.0 mL) at 50°C under an argon atmosphere.…”

“…[17] Our group also engaged in the direct C3À H amination of quinoxalin-2(1H)-ones utilizing TMSN 3 as an amino source to synthesize primary 3-aminoquinoxalin-2(1H)-ones, which are important intermediates for the synthesis of biologically active 3-N-substituted quinoxalinone derivatives (Scheme 1c). [18] All above brilliant achievements showed the superiority in high atom and step economy, and featured excellent functional group tolerance with good yields under readily accessible conditions. However, we could not ignore that the introduction of sulfonamide groups into the C3 position of quinoxalin-2(1H)-ones via direct C3À H functionalization is still rare and challenging, taking into consideration the importance of sulfonamide moiety in medicinal chemistry.…”

Recent Developments in Direct C–H Functionalization of Quinoxalin-2(1H)-ones via Radical Addition Processes

“…Despite the above reports on the installation of secondary and tertiary amino groups at the C3-H position of quinoxalin-2(1H)-one derivatives, the introduction of a free NH 2 group to quinoxalin-2(1H)-ones via C-H functionalization is a challenging task. Zhang and co-workers 53 have reported an elegant oxidative approach towards the introduction of a free NH 2 group on quinoxalin-2(1H)-one derivatives under mild conditions. Ceric ammonium nitrate (CAN) was used as the oxidant and trimethylsilyl azide was used as the amine source (Scheme 61).…”