Ethyl chloroformate → 3-Amino-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester

HRID 1642332Notes

Reaction equation

HRID 1642332 reaction equation
[C:1](Cl)(=[O:5])[O:2][CH2:3][CH3:4].[CH2:7]([O:10][C:11]([C:13]1[O:20][C:19]2[C:18]([NH2:21])=[N:17][NH:16][C:15]=2[CH:14]=1)=[O:12])[CH2:8][CH3:9].C(N(C(C)C)CC)(C)C>O1CCCC1>[CH2:7]([O:10][C:11]([C:13]1[O:20][C:19]2[C:18]([NH2:21])=[N:17][N:16]([C:1]([O:2][CH2:3][CH3:4])=[O:5])[C:15]=2[CH:14]=1)=[O:12])[CH2:8][CH3:9]

Participants

5

Reactant 3

HCID 10928Ethyl chloroformateHCID 81531DiisopropylethylamineHCID 57358414Propyl 3-amino-1H-furo[3,2-c]pyrazole-5-carboxylate

Product 1

HCID 426017253-Amino-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl esterYield 97%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A solution of ethyl chlorocarbonate (4.90 mL, 51.7 mmol) in tetrahydrofuran (THF, 60 mL) was slowly added to a mixture of 3-Amino-1H-furo[3,2-c]pyrazole-5-carboxylic acid propyl ester (12.0 g, 50.2 mmol) and diisopropylethylamine (DIEA, 51.5 mL, 301 mmol) in THF (300 mL), maintaining the temperature between −5 and −10° C. The reaction was kept at the same temperature for 5 minutes then allowed to reach room temperature. The obtained mixture was evaporated to dryness under vacuum and the residue extracted with ethyl acetate (AcOEt) and water. The organic layer was separated, dried over sodium sulphate and evaporated to dryness. The resulting raw material was triturated with diethyl ether to give 13.7 g of the title compound as a white solid.

Workup

  1. temperaturemaintaining the temperature between −5 and −10° C
  2. customto reach room temperature
  3. customThe obtained mixture was evaporated to dryness under vacuum
  4. extractionthe residue extracted with ethyl acetate (AcOEt) and water
  5. customThe organic layer was separated
  6. dry with materialdried over sodium sulphate
  7. customevaporated to dryness
  8. customThe resulting raw material was triturated with diethyl ether

Sources & evidence

ORD record
ord-880d1076d86e45f093dcb8b2af692dc1
Source dataset
uspto-grants-2012_02
Patent number
US08119641B2

Reaction notes

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