Diethyl oxalacetate → Diethyl furo[3,2-b]pyridine-5,6-dicarboxylate

HRID 2073965Notes

Reaction equation

HRID 2073965 reaction equation
[NH2:1][C:2]1[CH:6]=[CH:5][O:4][C:3]=1[CH:7]=O.N(C1C=COC=1C=O)=[N+]=[N-].[C:19]([O:29][CH2:30][CH3:31])(=[O:28])[CH2:20][C:21]([C:23]([O:25][CH2:26][CH3:27])=[O:24])=O>C(O)C.N1CCCCC1>[O:4]1[C:3]2[C:2](=[N:1][C:20]([C:19]([O:29][CH2:30][CH3:31])=[O:28])=[C:21]([C:23]([O:25][CH2:26][CH3:27])=[O:24])[CH:7]=2)[CH:6]=[CH:5]1

Participants

6

Reactant 3

HCID 66951Diethyl oxalacetate2×HCID 41537763-Azidofuran-2-carbaldehydeHCID 122102113-Aminofuran-2-carbaldehyde

Product 1

HCID 13752504Diethyl furo[3,2-b]pyridine-5,6-dicarboxylateYield 24%

Reagents, catalysts & solvents 2

HCID 8082PiperidineCatalystHCID 702EthanolSolvent

Procedure

3-Amino-2-formylfuran, prepared from 3-azido-2-formylfuran (8.9 g 0.065 mol) is dissolved in ethanol and to this solution diethyl oxalacetate (12.23 g, 0.065 mol) and ten drops of piperidine are added. In addition pulverized 3A° molecular sieve is added and the reaction stirred at 65°-60° C. for three hours, then additional diethyl oxalacetate (2.2 g) is added. The reaction is essentially complete after 12 hours at 55°-60° C. On cooling the reaction is filtered, and the filtrate concentrated and then dissolved in ethyl acetate, water washed, then brine washed, dried over anhydrous magnesium sulfate and stripped to dryness. The residue is dissolved in 3:1 hexane:ethyl acetate and passed through a flash chromatographic column in two stages. First it is filtered by vacuum through a four to five inch pad of silica from which the last three fractions containing the required product are collected and combined. These combined fractions are then passed through a six inch column eluting under pressure with ethyl acetate:hexane 3:1 and 2.1. Diethyl furo[3,2-b]-pyridine-5,6-dicarboxylate 4.15 g (24%) is obtained after crystallization from hexane-ether, of mp 60°64° C., and with a mas spectrum m/e of 264.

Workup

  1. additionare added
  2. additionIn addition
  3. additionis added
  4. waitThe reaction is essentially complete after 12 hours at 55°-60° C
  5. temperatureOn cooling the reaction
  6. filtrationis filtered
  7. concentrationthe filtrate concentrated
  8. dissolutiondissolved in ethyl acetate
  9. washwater washed
  10. washbrine washed
  11. dry with materialdried over anhydrous magnesium sulfate
  12. dissolutionThe residue is dissolved in 3:1 hexane
  13. filtrationFirst it is filtered by vacuum through a four to five inch pad of silica from which the last three fractions
  14. additioncontaining the required product
  15. customare collected
  16. washeluting under pressure with ethyl acetate:hexane 3:1 and 2.1

Sources & evidence

ORD record
ord-7ac6b5b022b74228a3ac4d04cac4611c
Source dataset
uspto-grants-1990_04
Patent number
US04920226

Reaction notes

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