Potassium Hydroxide → Potassium 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylate

HRID 1178759Notes

Reaction equation

HRID 1178759 reaction equation
[OH-].[K+:2].[K].[N:4]1[N:5]2[CH2:14][CH2:13][CH2:12][C:6]2=[CH:7][C:8]=1[C:9]([O-:11])=[O:10].N1N2CCCC2=CC=1C(OCC)=O.N1N2CCCC2=C(C(OCC)=O)C=1>C(O)C.CC(O)C.C(O)CC.CO>[N:4]1[N:5]2[CH2:14][CH2:13][CH2:12][C:6]2=[CH:7][C:8]=1[C:9]([O-:11])=[O:10].[K+:2]

Participants

10

Reactant 5

HCID 14797Potassium HydroxideHCID 5462222PotassiumHCID 12841166ethyl 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylateHCID 12841167Ethyl 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylateHCID 863069925,6-dihydro-4H-pyrrolo[2,1-e]pyrazole-2-carboxylate

Product 1

HCID 58975587Potassium 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylateYield 81%

Reagents, catalysts & solvents 4

HCID 702EthanolSolvent2×HCID 887MethanolSolventHCID 10311-PropanolSolventHCID 3776IsopropanolSolvent

Procedure

Preferred reaction solvents are alcohols selected from methanol, ethanol, 1-propanol and 2-propanol. Preferred reaction temperatures are in the range of about 15-40° C. Especially preferred is the alkali metal hydroxide, potassium hydroxide (85% w/w) in reaction solvent 2B (anhydrous) ethanol in the temperature range of about 15-30° C. Said especially preferred method is used for the preparation of the especially preferred, potassium salt of 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylate, using a ratio in the range of about 1.5:1 to about 2.5:1 mixture of the ethyl esters, ethyl 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylate and ethyl 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylate, respectively. The product, potassium 5,6-dihydro-4H-pyrrolo-[1,2-b]pyrazole-2-carboxylate, is obtained in at least 81% yield (after a reaction time of about 4-7 hours at about 15-22° C.). However, if impurities (such as potassium 5,6-dihydro-4H-pyrrolo-[1,2-b]pyrazole-3-carboxylate) are present they may optionally be removed by slurrying in 2B ethanol (anhydrous).

Workup

  1. customPreferred reaction temperatures
  2. customare in the range of about 15-40° C
  3. customis used for the preparation of the

Sources & evidence

ORD record
ord-7a268fb9876a416a86c6e7a7f4634f17
Source dataset
uspto-grants-2007_10
Patent number
US07276611B2

Reaction notes

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