Dabco → Ethyl 1-oxa-2-azaspiro[4.5]dec-2-ene-3-carboxylate

HRID 1518109Notes

Reaction equation

HRID 1518109 reaction equation
[CH2:1]=[C:2]1[CH2:7][CH2:6][CH2:5][CH2:4][CH2:3]1.[CH2:8]([O:10][C:11](=[O:16])[CH2:12][N+:13]([O-])=[O:14])[CH3:9].C1N2CCN(CC2)C1>CCO>[O:14]1[C:2]2([CH2:7][CH2:6][CH2:5][CH2:4][CH2:3]2)[CH2:1][C:12]([C:11]([O:10][CH2:8][CH3:9])=[O:16])=[N:13]1

Participants

5

Reactant 3

HCID 9237DabcoHCID 14502MethylenecyclohexaneHCID 69379Ethyl nitroacetate

Product 1

HCID 59280111Ethyl 1-oxa-2-azaspiro[4.5]dec-2-ene-3-carboxylateYield 64%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Conditions

Temperature
80 °C

Procedure

To a 300 mL pressure vessel equipped with a magnetic stir bar was added methylenecyclohexane (5.83 g, 60.6 mmol) and EtOH (150 mL). Nitro-acetic acid ethyl ester (16.8 mL, 152 mmol) and DABCO (680 mg, 6.06 mmol) were then added. Additional EtOH (30 mL) was added to rinse the sides of the vessel, which was tightly capped. The mixture was heated to 80° C. for 42 h and then cooled to RT. The solvent was removed under reduced pressure, and the residue was divided into three equal portions. Each portion was purified by column chromatography using an 80-g SiO2 pre-packed column eluting with EtOAc/hexanes, 0:1 to 1:4, v/v over 30 min, yielding 8.12 g (64%) of the desired ester. 1H-NMR (400 MHz, CDCl3) δ: 4.34 (q, J=7.2 Hz, 2H), 2.91 (s, 2H), 1.71-1.88 (m, 4H), 1.60-1.71 (m, 2H), 1.39-1.53 (m, 4H), 1.37 (t, J=7.1 Hz, 3H).

Workup

  1. customTo a 300 mL pressure vessel equipped with a magnetic stir bar
  2. washto rinse the sides of the vessel, which
  3. customwas tightly capped
  4. temperaturecooled to RT
  5. customThe solvent was removed under reduced pressure
  6. customEach portion was purified by column chromatography
  7. washeluting with EtOAc/hexanes, 0:1 to 1:4, v/v over 30 min

Sources & evidence

ORD record
ord-a7575c5bb32f418985e1521db5215578
Source dataset
uspto-grants-2012_07
Patent number
US08232409B2

Reaction notes

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