Synthesis and rearrangement of 4-imino-4H-3,1-benzoxazines

Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-ones: Rearrangement of pyrrolo[1,2-d][1,3,4]oxadiazines and regioselective intramolecular cyclization of 1,2-biscarbamoyl-substituted 1H-pyrroles

“…To synthesize the desired pyrrolotriazinones 12 regioselectively we initially considered the work of Mazurkiewicz [20–21]. He reported that a mixture of 4 H -3,1-benzoxazines ( O -imidoylation products) and 4-quinazolones ( N -imidoylation products) could be obtained after heating N -acylanthranilamides in CH 2 Cl 2 under reflux with PPh 3 Br 2 in the absence of triethylamine.…”

“…In his research, it was proved that HCl or HBr influenced the rearrangement of benzoxazines to quinazolones. Importantly, triethylamine was considered to be an HBr captor [20–21]. …”

“…3) [20–28]. For example, it is not reasonable to consider Mazurkiewicz’s acid-promoted rearrangement [20–21], because oxadiazine is not stable under acidic conditions. In the case of the rearrangement of 11a to 12a , the mechanism of the nucleophile-induced cyclization is proposed after considering Hart’s research on the synthesis of fumiquinazolines [22].…”

UV-Light-Induced Dehydrogenative N-Acylation of Amines with 2-Nitrobenzaldehydes To Give 2-Aminobenzamides

“…In addition, AcOH could promote this reaction better than oxalic acids and fumaric acid (entry 11, [13][14][15]. The bases showed negative effect on this transform due to possibly inhibit the formation of 2-nitrosobenzoic acid (entry [16][17][18]. Subsequently, we considered on the light sources and found that the UV light (365-375 nm) exhibited the highest yield in 78% yield (entry 11, 19 and 20).…”

Synthesis and characterization of a novel heterocycle: 1‐Substituted‐4‐arylazamethylene‐6‐arylpyrazolo[5,4‐d]‐1,3‐oxazine

“…As shown in Figure 1, quinazolinones 1 have been investigated synthetically [1][2][3][4], pharmacologically [2,4], and corresponding rearrangement isomers 2 were also studied for applications in medicinal chemistry [3,[5][6][7][8][9][10][11][12][13][14] as well as in plant pest control [15]. The 1-aryl-or alkylsubstituted-5-hydropyrazolo [5,4-d]pyrimidin-4-one 3 were also well known synthetically [16][17][18].…”