Synthesis Of 4-nitropyridine-N-oxide Derivatives

In this thesis,3-fluoro-4-nitro-N-oxide was prepared from starting material 3-fluoro-pyridine by N-Oxidation and nitration.Three kinds of derivatives of 4-nitro-pyridine-N-oxide were synthesised by amination, methoxylation and ethoxylation.Then,3-methoxy-4-amino pyridine and 3-ethoxy-4-amino pyridine were prepared based on the reduction reaction of 3-methoxy-4-nitro-pyridine-N-oxide and 3-ethoxy-4-nitro-pyridine-N-oxide using 85% hydrazine hydrate as the reducing agent and palladium carbon as catalyst. Factors which influenced on reaction were investigated and the optimal technological conditions of unit reaction were optimized.It was shown that the optimum N-Oxidation conditions was reaction time 20h, reaction temperature 70℃,30%H2O2, V (3-fluoropyridine):V (30% H2O2)=1:4. Nitration optimum conditions was reaction temperature 80℃, reaction time 4h, mixed acid ratio of V (fuming nitric acid):V(fuming sulfuric acid)=1:1.5. Amination of the optimum conditions was reaction temperature 50℃, reaction time 30min. Methoxylation optimum conditions was reaction temperature 60-70℃, reaction time 2h, n(methanol sodium):n (3-fluoro-4-nitropyridine-1-oxide)=1:1.05. ethoxylation optimum conditions was reaction temperature 80℃, reaction time 3h, n(ethanol sodium):n(3-fluoro-4-nitropyridine-1-oxide)=1:1.5. The. optimum reduction conditions was reaction temperature 80℃, reaction time 4h, n(nitro compounds):n(hydrazine hydrate)=1:6, catalyst 0.8g. The final product was characterized by MS and1HNMR.