Successive Formation of Two Amide Linkages between Two Benzene Rings

Abstract

To successively construct two amide bonds between two benzene rings, the reaction of methyl N-alkylanthranilate and N-alkylisatoic anhydride in the presence of a base was studied. When the reaction was carried out with lithium hexamethyldisilazide and N,N,N′,N′-tetramethylethylenediamine in THF at 70 °C under reduced pressure, a cyclic diamide was obtained in high yield.

Polymerization of 4,6-diaminoisophthalic acid-type monomers bearing anthranilic acid ester and isatoic anhydride moieties

“…9 The reaction tube was sealed after the pressure inside the tube had been reduced, and the reaction mixture was heated at 70°C for 1 h. SEC analysis of the reaction mixture revealed that the reaction almost ceased in 5 min despite incomplete consumption of the monomers, and an oligomeric product (M n = 2040, M w = 3020) was formed ( Figure 1a). As shown in Figure 2a, the MALDI-TOF mass spectrum of the crude product showed molecular ion peaks whose m/z values agreed with the molecular weight of the linear-type products, such as A − (BA) n − A type oligomers 9 (n = 1-3) and an amideterminated oligomer 10 ( Figure 3).…”

“…In these polymerizations, the deprotonated amide ion of the monomer attacks the carbonyl group adjacent to the benzene ring at the isatoic anhydride moiety of another monomer, leading to the formation of an amide linkage and a carbamate ion. 9 If decarbonation of the carbamate ion occurs and the formed amide ion attacks the neighboring ester moiety, the ladder structure will be obtained. We believe that the electron-withdrawing carbonyl group at the para position of the nitrogen atom of 2 and 4 reduces the nucleophilicity of the amide ion formed by the decarbonation, retarding the formation of the ladder structure.…”

“…To synthesize this type of ladder polymer, we investigated the condensation reaction between N-alkylanthranilic acid methyl ester and N-alkylisatoic anhydride in the presence of a strong base, and developed a reaction that constructed two amide linkages successively between two benzene rings. 9 The use of lithium 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS) as a base and N,N,N',N'-tetramethylethylenediamine (TMEDA) as an additive in the model reaction resulted in high yield of the target compound. For the synthesis of a ladder polyamide using this reaction between A 2 -and B 2 -type monomers, we designed the monomers 1 and 2; their polymerization was expected to afford the aromatic ladder polyamide 3 (Scheme 1).…”

Polymerization of 2,5‐diaminoterephthalic acid‐type monomers for the synthesis of polyamides containing ladder unit

“…Aiming to synthesize ladder‐type aromatic polyamides, we studied the reaction between N ‐methylanthranilic acid methyl ester ( 1 ) and N ‐methylisatoic anhydride ( 2 ) in the presence of a strong base as a model reaction and observed that the use of lithium hexamethyldisilazide (LiHMDS) as a base resulted in exclusive formation of two amide linkages successively between the two benzene rings to afford 3 (Scheme ) . For the synthesis of ladder polymers using this reaction, the polymerization of 4,6‐diaminoisophthalic acid monomers 4 bearing an anthranilic acid ester moiety and an isatoic anhydride moiety was investigated.…”

Crystal Structure of <i>N</i>-Isopropylanthranilic Acid Trimer

“…As in the case of the reaction we reported previously, 8 the dimer methyl ester was synthesized by the reaction of methyl N-isopropylanthranilate with N-isopropylisatoic anhydride in…”