Potassium Hydroxide → 4,5-Dimethyl-3,6-dihydro-2H-pyran-2,2-dicarboxylic acid

HRID 2396119Notes

Reaction equation

HRID 2396119 reaction equation
[CH3:1][C:2]1[CH2:3][C:4]([C:14]([O:16]CC)=[O:15])([C:9]([O:11]CC)=[O:10])[O:5][CH2:6][C:7]=1[CH3:8].[OH-].[K+]>O1CCCC1>[CH3:1][C:2]1[CH2:3][C:4]([C:14]([OH:16])=[O:15])([C:9]([OH:11])=[O:10])[O:5][CH2:6][C:7]=1[CH3:8]

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 109561712H-Pyran-2,2-dicarboxylic acid, 3,6-dihydro-4,5-dimethyl-, diethyl ester

Product 1

HCID 189882674,5-Dimethyl-3,6-dihydro-2H-pyran-2,2-dicarboxylic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Part B. A solution of the ester compound prepared in Part A above (9.63 g, 37.6 mmol) in tetrahydrofuran (150 mL) was treated with an aqueous solution of potassium hydroxide (150 mL, 10N, 1.5 mol), and stirred vigorously at ambient temperature for 48 hours. The solid salt was collected by filtration, and neutralized by dissolving into 1N aqueous hydrochloric acid (200 mL). This was extracted with ethyl acetate (2×200 mL), and the extracts were combined, dried over anhydrous sodium sulfate, filtered and evaporated to afford the product, 3,6-dihydro-4,5-dimethyl-2H-pyran-2,2-dicarboxylic acid, as a waxy solid (7.46 g, 37.3 mmol, 99%). 1H NMR (CDCl3): δ 4.16 (2H, br s); 2.57 (2H, br s); 1.68 (3H, br s); 1.51 (3H, br s). Mass spectrum (NH3 -CI/DDIP): no M+H+ observed.

Workup

  1. filtrationThe solid salt was collected by filtration
  2. dissolutionby dissolving into 1N aqueous hydrochloric acid (200 mL)
  3. extractionThis was extracted with ethyl acetate (2×200 mL)
  4. dry with materialdried over anhydrous sodium sulfate
  5. filtrationfiltered
  6. customevaporated

Sources & evidence

ORD record
ord-69c4f29c16244b26a454c4c63c325c26
Source dataset
uspto-grants-1996_02
Patent number
US05491152

Reaction notes

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