Methylparaben → Benzoic acid, 4-[(tetrahydro-2H-pyran-2-yl)oxy]-, methyl ester

HRID 257306Notes

Reaction equation

HRID 257306 reaction equation
[OH:1][C:2]1[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][CH:3]=1.[O:12]1[CH:17]=[CH:16][CH2:15][CH2:14][CH2:13]1>S(=O)(=O)(O)O>[O:12]1[CH2:17][CH2:16][CH2:15][CH2:14][CH:13]1[O:1][C:2]1[CH:3]=[CH:4][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:10][CH:11]=1

Participants

4

Reactant 2

HCID 7456MethylparabenHCID 80803,4-dihydro-2H-pyran

Product 1

HCID 11770459Benzoic acid, 4-[(tetrahydro-2H-pyran-2-yl)oxy]-, methyl ester

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidCatalyst

Procedure

To a solution of 0.64 mL (2 mmol) of 1-(2-trimethylsiloxyethoxy)-1-trimethylsiloxy-2-methyl-1-propene, 0.55 mL of tetrabutylammonium biacetate (0.04 M in THF), and 0.06 mL of bis(dimethylamino)methylsilane in 40 mL of THF was added dropwise a solution of 20 g (72.5 mmol) of 4-tetrahydropyranyloxybenzyl methacrylate (purified by passing over a column of basic alumina in hexane solution, followed by evaporation of the hexane under reduced pressure) in 30 mL of THF. When the exothermic polymerization was finished, and the temperature had returned to room temperature, the reaction mixture was poured into methanol. Filtration gave 19 g of poly(4-tetrahydropyranyloxybenzyl methacrylate). GPD: Mn =9390, Mw -11,500, MwMn =1.23. DSC: Tg =62.3° C., with a decomposition endotherm at 250.5° C. TGA: rapid loss of 24.74% of weight at 248.1° C. The monomer was prepared from methyl 4-hydroxybenzoate by reaction with an excess of 3,4-dihydro-2H-pyran in the presence of sulfuric acid catalyst to give methyl 4-(2-tetrahydropyranyloxy)benzoate, which was then reduced with lithium aluminum hydride in THF solution to give 4-(2-tetrahydropyranyloxy)benzyl alcohol. Esterification with methacrylyl chloride and triethylamine in dichloromethane solution gave 4-tetrahydropyranyloxybenzyl methacrylate, m.p. 36° C.

Workup

  1. customTg =62.3° C.
  2. customat 250.5° C
  3. customat 248.1° C

Sources & evidence

ORD record
ord-22f8485d787142848d932218c2fa5996
Source dataset
uspto-grants-1993_11
Patent number
US05262281

Reaction notes

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