6-Hydroxy-5-nitronicotinicacid

6-Hydroxynicotinic acid 2 (25.0 g, 180 mmol) was dissolved in HNOInto a 2000-mL round-bottom flask, was placed sulfuric acid (150 mL). This was followed by the addition of 6-hydroxypyridine-3-carboxylic acid (50 g, 359.43 mmol, 1.00 equiv), in portions at 0a) Compound 1 (25 g, 0.180 mol) was placed in a 500 mL recovery flask, and fuming nitric acid (1.52) (125 mL) was added. The flask was gradually heated using an oil bath while stirring, and stirring was conducted for 5 hours at 50° C. After stopping heating and allowing to cool to room temperature, the reaction solution was concentrated under reduced pressure. The residue obtained was cooled by an ice bath, and recrystallized using methanol as the solvent. Compound 2 (9.77 g, 0.053 mol) was obtained by drying the solid obtained by filtration, under reduced pressure. 1H NMR (300 MHz, CDA method for synthesizing 6-hydroxy-5-nitronicotinic acid comprises the following steps:(a) adding concentrated sulfuric acid and concentrated nitric acid sequentially into the reaction bottle, and stirring uniformly to obtain a reaction solution A, in which the molar ratio of concentrated sulfuric acid to concentrated nitric acid is 1: 5, the concentrated sulfuric acid used is 68percent The mass fraction of 86percent;(b) mixing the raw material 6-hydroxynicotinic acid and the catalyst ammonium bisulfate at a molar ratio of 60: 1 to obtain a reaction raw material B;(c) adding the reaction raw material B obtained in the step (b) to the reaction solution A obtained in the step (a) with stirring, and then carrying out the pre-nitration reaction by heating to 50 ° C. for 5 h, wherein the HNO 3 in the reaction solution A And 6-hydroxynicotinic acid in reaction raw material B is 1.0: 1;(d) The concentrated sulfuric acid and concentrated nitric acid (concentrated sulfuric acid used mass fraction of 68percent, concentrated nitric acid mass fraction of 86percent) at a molar ratio of 1: 5 mixed uniformly, and then added catalyst ammonium bisulfite Stir the reaction Solution C, wherein the molar ratio of concentrated nitric acid to the catalyst is 90: 1;(e) After the pre-nitrification reaction in the step (c) is completed, the reaction solution C obtained in the step (d) is added dropwise to the reaction flask in the step (c) under stirring and heated to 75 ° C for nitrification 14h, get nitrification reaction liquid;(f) The obtained nitration reaction liquid obtained in step (e) is crystallized at 4 DEG C for 26 hours, and the solid obtained by filtration under suction is crude product A. A method for separating and purifying the nitration reaction liquid of 6-hydroxy-5-nitronicotinic acid described above comprises the following steps:(1) rinsing the crude product A obtained in the above step (f) with cold methanol (2 ° C) and then vacuum drying to obtain a crude product B;(2) dissolving the crude product B obtained in the step (2) with an acidic aqueous solution having a pH value of 1 and then separating and purifying by a cooling crystallization method at a cooling rate of 1 ° C./min, a crystallization temperature of 4 ° C. and a crystallization time of 14 h Finally, the product 6-hydroxy-5-nitronicotinic acid was obtained.In this example, the yield of 6-hydroxy-5-nitronicotinic acid was 89.03percent and the conversion rate was 94.16percent. After isolation and purification in this Example, the product 6-hydroxy-5- The purity of nicotinic acid was 99.16percent.A)

Molecular Weight:184.11
XLogP3:-0.5
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:1
Exact Mass:184.01202123
Monoisotopic Mass:184.01202123
Topological Polar Surface Area:112
Heavy Atom Count:13
Complexity:349
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes