Methanol → methyl 1-hydroxy-1H-pyrazole-4-carboxylate

HRID 232017ノート

反応式

HRID 232017 の反応式
[OH:1][N:2]1[CH:6]=[C:5]([C:7]([OH:9])=[O:8])[CH:4]=[N:3]1.S(=O)(=O)(O)O.[CH3:15]O>>[OH:1][N:2]1[CH:6]=[C:5]([C:7]([O:9][CH3:15])=[O:8])[CH:4]=[N:3]1

参加物

4

反応物 3

HCID 887MethanolHCID 1118Sulfuric AcidHCID 137994111-Hydroxypyrazole-4-carboxylic acid

生成物 1

HCID 13823205methyl 1-hydroxy-1H-pyrazole-4-carboxylate収率 91%

実験手順

90 g of 1-hydroxypyrazole-4-carboxylic acid (for preparation, see corresponding German Patent Application No. P 35 32 879.7) are suspended in 500 ml of methanol, and 10 ml of concentrated sulfuric acid are added. The mixture is then refluxed for 12 hours, the methanol is distilled off under reduced pressure, the solid residue is stirred in 400 ml of water, the solution is brought to pH 3 with sodium hydroxide solution, and the product is filtered off under suction and washed with water. The mother liquor is evaporated down, and a further crystalline fraction is obtained. The combined products are dried under reduced pressure to give 91 g (91% of theory) of methyl 1-hydroxypyrazole-4-carboxylate of melting point 175°.181° C. NMR (DMSO-D6): 8.35 s [1]; 7.82 s [1]; 3.80 s [3].

後処理

  1. temperatureThe mixture is then refluxed for 12 hours
  2. distillationthe methanol is distilled off under reduced pressure
  3. filtrationthe product is filtered off under suction
  4. washwashed with water
  5. customThe mother liquor is evaporated down
  6. customa further crystalline fraction is obtained
  7. customThe combined products are dried under reduced pressure

出典と根拠

ORDレコード
ord-877102d6cf1b489997739dc4a79e23ea
出典データセット
uspto-grants-1989_07
特許番号
US04851410

反応ノート

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