4-Hydroxybenzaldehyde → 5-(4-Hydroxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione

HRID 2101779Notes

Reaction equation

HRID 2101779 reaction equation
[CH3:1][C:2]1([CH3:10])[O:9][C:7](=[O:8])[CH2:6][C:4](=[O:5])[O:3]1.[OH:11][C:12]1[CH:19]=[CH:18][C:15]([CH:16]=O)=[CH:14][CH:13]=1>O>[OH:11][C:12]1[CH:19]=[CH:18][C:15]([CH:16]=[C:6]2[C:7](=[O:8])[O:9][C:2]([CH3:10])([CH3:1])[O:3][C:4]2=[O:5])=[CH:14][CH:13]=1

Participants

4

Reactant 2

HCID 1264-HydroxybenzaldehydeHCID 162492,2-Dimethyl-1,3-dioxane-4,6-dione2×

Product 1

HCID 3705415-(4-Hydroxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dioneYield 94%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

Condensation with Meldrum's acid was carried out according to the method of Bigi et. al. Tet. Lett. 2001, 42, 5203-5205. A 2 L pear-shaped flask was charged with 4-hydroxybenzaldehyde (50 g, 409 mmol) (commercially available from Aldrich) and water (400 mL). The flask was placed in a water bath at 75° C. and Meldrum's acid (62 g, 430 mmol) (commercially available from Aldrich) was added as a slurry in water (400 mL). The reaction mixture was agitated for 2 hours and then cooled in an ice bath for 2 hours. The product was collected by filtration and rinsed with cold water. After drying thoroughly, 95 g (94%) of adduct 21.1 was obtained as a fine yellow powder. 1H NMR (500 MHz) (DMSO-d6) δ 9.75 (br s, 1H); 8.27 (s, 1H); 8.24 (d, 2H, J=10 Hz); 6.98 (d, 2H, J=10 Hz), 1.76 (s, 6H). MS ESI (pos.) m/e: 519.0 (2M+Na).

Workup

  1. customThe flask was placed in a water bath at 75° C.
  2. temperaturecooled in an ice bath for 2 hours
  3. filtrationThe product was collected by filtration
  4. washrinsed with cold water
  5. customAfter drying thoroughly

Sources & evidence

ORD record
ord-2ae6a4a9c31043198723a9e28fb2df49
Source dataset
uspto-grants-2009_08
Patent number
US07572934B2

Reaction notes

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