“…Furthermore, hydroxy benzotriazole (HOBt) can be used to synthesize amides, but concerns about its explosive properties have been raised [24]. However, 2-methyl-6-nitrobenzoic anhydride (MNBA) demonstrated great promise in the synthesis of large-ring lactones [25], artificial glutamate analogs [26], and carboxylic esters [27]. Further, the combination of MNBA, 4-(dimethylamino)pyridine (DMAP) or 4-(dimethylamino)pyridine N-oxide (DMAPO) was also effective for the synthesis of amides and peptides [28,29].…”