Hydrochloric Acid → 2-(Pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic Acid

HRID 751260Notes

Reaction equation

HRID 751260 reaction equation
[O-]CC.[Na+].C1(C)C=CC=CC=1.O=[C:13]1[CH2:17][CH2:16][CH2:15][N:14]1[N:18]=[C:19]([C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][N:25]=1)[CH2:20][C:21]([OH:23])=[O:22].Cl>O>[N:25]1[CH:26]=[CH:27][CH:28]=[CH:29][C:24]=1[C:19]1[C:20]([C:21]([OH:23])=[O:22])=[C:13]2[CH2:17][CH2:16][CH2:15][N:14]2[N:18]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 1140TolueneHCID 2723922Sodium ethoxideHCID 866038563-(2-Oxo-pyrrolidin-1-ylimino)-3-pyridin-2-yl-propionic acid

Product 1

HCID 597100292-(Pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic AcidYield 93.2%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
100 °C

Procedure

Add sodium ethoxide (145 g, 2.03 mol), followed by toluene (7 L) and 3-(2-oxo-pyrrolidin-1-ylimino)-3-pyridin-2-yl-propionic acid (280 g, 1.02 mol) to a 22 L flask equipped with mechanical stirrer, nitrogen inlet and a reflux condenser. Heat the mixture to 100° C. for 21 h. Cool to room temperature. Add water (6 L) and adjust to pH 5 with concentrated hydrochloric acid. Separate the organic layer and extract the aqueous layer with 10% isopropyl alcohol in chloroform (2×9 L). Combine the organic layers, dry (sodium sulfate), filter and concentrate in vacuo to yield the title compound as a yellow solid (218 g, 93%). MS ES+ m/e 230 (M+1).

Workup

  1. customequipped with mechanical stirrer, nitrogen inlet and a reflux condenser
  2. temperatureCool to room temperature
  3. customSeparate the organic layer
  4. extractionextract the aqueous layer with 10% isopropyl alcohol in chloroform (2×9 L)
  5. dry with materialCombine the organic layers, dry (sodium sulfate)
  6. filtrationfilter
  7. concentrationconcentrate in vacuo

Sources & evidence

ORD record
ord-0bc7bfb7549041d49cc6882f5538098b
Source dataset
uspto-grants-2008_07
Patent number
US07405299B2

Reaction notes

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