关键词: 4-(5-硝基-6-羟基-7-甲基苯并噁唑-2-基)苯甲酸甲酯, 合成, 4-[N-(2, 4-二羟基-3-甲基-5-硝基苯基)氨甲酰基]苯甲酸甲酯, 甲基改性PBO

Abstract: Aiming to change the poor compression performance and processing difficulties of PBO fiber,a novel monomer precursor compound,methyl 4-(5-nitro-6-hydroxy-7-methylbenzoxazol-2-yl) benzoate (MMNB),was proposed,and synthesized with total yield of 56.42%,and a purity of 97.5%. It can be used for the preparation of AB-type monomer and methyl modified PBO fiber,to improve the processability of PBO fibers and increase the axial compressive strength after heat-crosslinking. The results showed that intermediate methyl 4-[N-(2,4-dihydroxy-3-methyl-5-nitrophenyl) carbamoyl] benzoate(MNHB) was one-pot prepared by the chloride of monomethyl terephthalate (MTA),then condensed with 2-methyl-4-amino-6-nitroresorcinol hydrochloride (MANR·HCl) in methylene chloride solvent and triethylamine as acid binding agent,yield reached 73.65%. MMNB was synthesized by cyclization dehydration of MNHB in diglyme solvent with the presence of polyphosphoric acid,and yield reached 76.61%. Their molecular structures were confirmed by IR,MS and ¹H NMR.

Key words: methyl 4-(5-nitro-6-hydroxy-7-methylbenzoxazol-2-yl) benzoate, synthesis, methyl 4-[N-(2,4-di hydroxy-3-methyl-5-nitrophenyl)carbamoyl] benzoate, methyl modified PBO