ChemicalBook CAS DataBase List 4,6-dihydroxypyridazine-3-carboxylicacid

4,6-dihydroxypyridazine-3-carboxylicacid synthesis

5synthesis methods

Product Name:4,6-dihydroxypyridazine-3-carboxylicacid
CAS Number:1442437-21-9
Molecular formula:C5H4N2O4
Molecular Weight:156.1

ethyl 4,6-dihydroxypyridazine-3-carboxylate

1352925-63-3
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4,6-dihydroxypyridazine-3-carboxylicacid

1442437-21-9
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Yield:1442437-21-9 88%

Reaction Conditions:

with water;lithium hydroxide in tetrahydrofuran;methanol at 20;

Steps:

2 Step 2
In a 5000 ml rb flask, ethyl 4,6-dihydroxypyridazine-3-carboxylate (200 g, 1086 mmol) was dissolved in THF (2000 mL), methanol (1000 mL) and water (800 mL). LiOH (137 g, 3258 mmol) was added slowly at rt and stirred at rt for 3-4 hr.
The starting material was gone.
The solvent was removed at 50° C. under reduced pressure to afford a yellow solid.
The solid was acidified with aqueous HCl solution (400 ml) (1:1 ratio) at 0° C. and stirred at rt for 30-40 minutes.
The solid was filtered and washed with water.
It was then dried under vacuum for 1-2 hr.
This solid was taken into 300 ml of methanol:DCM (2:8) and stirred at rt for 20-25 minutes.
The mixture was filtered and the solid was washed with methanol and dried under vacuum for 1 hr.
The desired product was obtained as a yellow solid, 4,6-dihydroxypyridazine-3-carboxylic acid (153 g, 951 mmol, 88% yield).
MS (M+1) m/z: 156.9 (MH⁺). LC retention time 0.31 min [A].
¹H NMR (400 MHz, deuterium oxide) δ 6.00-5.34 (m, 1H), 4.75 (s, 7H)

References:

BRISTOL-MYERS SQUIBB COMPANY;Liu, Chunjian;Yang, Michael G.;Xiao, Zili;Chen, Ling;Moslin, Ryan M.;Tokarski, John S.;Weinstein, David S. US2019/152948, 2019, A1 Location in patent:Paragraph 0429-0431; 0426

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372118-00-8 Synthesis