Water → 6-(4-Tert-butyl-phenyl)-4-oxo-4,5-dihydro-pyrazolo[1,5-a]pyrazine-2-carboxylic acid ethyl ester

HRID 2272953Notes

Reaction equation

HRID 2272953 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[CH:10]=[C:9]([C:11](OCC)=[O:12])[N:8]([CH2:16][C:17]([C:19]2[CH:24]=[CH:23][C:22]([C:25]([CH3:28])([CH3:27])[CH3:26])=[CH:21][CH:20]=2)=O)[N:7]=1)=[O:5])[CH3:2].C([O-])(=O)C.[NH4+:33].O>C(O)(=O)C>[CH2:1]([O:3][C:4]([C:6]1[CH:10]=[C:9]2[C:11](=[O:12])[NH:33][C:17]([C:19]3[CH:24]=[CH:23][C:22]([C:25]([CH3:28])([CH3:27])[CH3:26])=[CH:21][CH:20]=3)=[CH:16][N:8]2[N:7]=1)=[O:5])[CH3:2]

Participants

5

Reactant 3

HCID 962WaterHCID 517165Ammonium AcetateHCID 898321591-[2-(4-tert-butyl-phenyl)-2-oxo-ethyl]-1H-pyrazole-3,5-dicarboxylic acid diethyl ester

Product 1

HCID 898263626-(4-Tert-butyl-phenyl)-4-oxo-4,5-dihydro-pyrazolo[1,5-a]pyrazine-2-carboxylic acid ethyl ester

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of 1.04 g (2.71 mmol) 1-[2-(4-tert-butyl-phenyl)-2-oxo-ethyl]-1H-pyrazole-3,5-dicarboxylic acid diethyl ester and 2.08 g (27.1 mmol) ammonium acetate in 20 ml acetic acid is stirred for 44 hours at 110° C. The reaction mixture is cooled to room temperature and excess water is added. The resulting precipitate is filtered off, and washed with water. The residue is chromatographed on a silica gel column with dichloromethane/methanol as eluent to give 6-(4-tert-butyl-phenyl)-4-oxo-4,5-dihydro-pyrazolo[1,5-a]pyrazine-2-carboxylic acid ethyl ester as colourless crystals; HPLC/MS 2.41 (A), [M+H] 340.

Workup

  1. filtrationThe resulting precipitate is filtered off
  2. washwashed with water
  3. customThe residue is chromatographed on a silica gel column with dichloromethane/methanol as eluent

Sources & evidence

ORD record
ord-cb3e9600b2214fd4b5839bf771bcc3b3
Source dataset
uspto-grants-2015_09
Patent number
US09120805B2

Reaction notes

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