Ethylene Glycol → Ethyl 8-ethyl-1,4-dioxaspiro[4,4]nonane-7-carboxylate

HRID 1969880Notes

Reaction equation

HRID 1969880 reaction equation
[CH2:1]([CH:3]1[CH2:7][C:6](=[O:8])[CH2:5][CH:4]1[C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH3:2].[CH2:14](O)[CH2:15][OH:16].C(OC(OCC)OCC)C.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C(Cl)Cl.CCOC(C)=O>[CH2:1]([CH:3]1[CH2:7][C:6]2([O:16][CH2:15][CH2:14][O:8]2)[CH2:5][CH:4]1[C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH3:2]

Participants

7

Reactant 4

HCID 174Ethylene GlycolHCID 31214Ethyl orthoformateHCID 521998p-Toluenesulfonic acid monohydrateHCID 58010012Cyclopentanecarboxylic acid, 2-ethyl-4-oxo-, ethyl ester

Product 1

HCID 58557462Ethyl 8-ethyl-1,4-dioxaspiro[4,4]nonane-7-carboxylateYield 86.5%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8857Ethyl AcetateSolvent

Procedure

A round bottom flask was charged with ethyl 2-ethyl-4-oxocyclopentanecarboxylate (1.5 g, 8.1 mmol, Example #22, Step B) in DCM (22 mL). To the flask were added ethylene glycol (0.91 mL, 16 mmol), triethylorthoformate (2.0 mL, 12 mmol), and p-toluenesulfonic acid monohydrate (0.31 g, 1.6 mmol). The reaction mixture was stirred at rt for about 24 h. The solution was concd under reduced pressure to give brown oil that was dissolved in EtOAc and purified by silica gel chromatography eluting with a gradient of 0-50% EtOAc in heptane. The product containing fractions were combined and concd to dryness under reduced pressure to give ethyl 8-ethyl-1,4-dioxaspiro[4,4]nonane-7-carboxylate as a light yellow oil (1.6 g, 83%): LC/MS (Table 1, Method c) MS m/z 229 (M+H)+; 1H NMR (CDCl) δ 4.14 (q, 2H), 3.90 (m, 4H), 2.99 (q, 1H), 2.32-2.27 (m, 1H), 2.26-2.11 (m, 1H), 2.05-1.99 (m, 1H), 1.96-1.91 (m, 1H), 1.83-1.78 (m, 1H), 1.46-1.39 (m, 1H), 1.31-1.24 (m, 1H), 1.26 (t, 3H), 0.90 (t, 3H).

Workup

  1. customto give brown oil that
  2. custompurified by silica gel chromatography
  3. washeluting with a gradient of 0-50% EtOAc in heptane
  4. additionThe product containing fractions

Sources & evidence

ORD record
ord-d32f462ea6ff4b2f9d6012fa50a02ef7
Source dataset
uspto-grants-2013_04
Patent number
US08426411B2

Reaction notes

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