Tetrahydrofuran → ethyl 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylate

HRID 2427058Notes

Reaction equation

HRID 2427058 reaction equation
CON=[C:4]([CH2:10][C:11](=O)[CH3:12])[C:5]([O:7][CH2:8][CH3:9])=[O:6].[Cl:14][C:15]1[C:16]([NH:21][NH2:22])=[N:17][CH:18]=[CH:19][CH:20]=1.O1CCCC1>C(O)(=O)C>[Cl:14][C:15]1[C:16]([N:21]2[C:4]([C:5]([O:7][CH2:8][CH3:9])=[O:6])=[CH:10][C:11]([CH3:12])=[N:22]2)=[N:17][CH:18]=[CH:19][CH:20]=1

Participants

5

Reactant 3

HCID 8028TetrahydrofuranHCID 5561003-Chloro-2-hydrazinylpyridineHCID 589173Ethyl 2-(methoxyimino)-4-oxopentanoate

Product 1

HCID 66854396ethyl 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylateYield 15.8%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of 1.34 g of ethyl 2-methoxyimino-4-oxopentanoate, 1.23 g of 3-chloro-2-hydrazinopyridine, 25 ml of tetrahydrofuran and 50 ml of acetic acid was heated to reflux for 8 hours. The reaction mixture was concentrated under reduced pressure. Water was poured into the residue, and the mixture was extracted with methyl t-butyl ether two times. The combined organic layer was washed successively with a 1N aqueous sodium hydroxide solution, water and an aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography to obtain 0.30 g of ethyl 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylate of the formula:

Workup

  1. temperaturewas heated
  2. temperatureto reflux for 8 hours
  3. concentrationThe reaction mixture was concentrated under reduced pressure
  4. additionWater was poured into the residue
  5. extractionthe mixture was extracted with methyl t-butyl ether two times
  6. washThe combined organic layer was washed successively with a 1N aqueous sodium hydroxide solution, water
  7. dry with materialan aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate
  8. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-011b84585c274ff3a76c6c611ddbf295
Source dataset
uspto-grants-2011_06
Patent number
US07968573B2

Reaction notes

Loading…