Methylparaben → Methyl 4-hydroxycyclohexanecarboxylate

Temperature

40 °C

A Parr bottle was charged with 150 ml of methanol and 25 g of methyl 4-hydroxybenzoate was added, then the bottle was flushed with nitrogen, 2.5 g of 5% rhodium on alumina was added and the reaction mixture was pressurized under hydrogen at 3.74 atmospheres for 18 hours with constant shaking. The reaction was then flushed with nitrogen and filtered through diatomaceous earth to remove the catalyst. The diatomaceous earth was rinsed with methanol, being careful not to filter the catalyst to dryness. The filtrates were combined and the methanol was removed under reduced pressure with very gentle heat (ca. 40° C.). The residue of product and alumina was taken up in 200 ml of ether to which 3 g of anhydrous potassium carbonate was added. The precipitated alumina and potassium carbonate were removed by filtration through diatomaceous earth. This was rinsed with ether, the filtrates were combined and the solvent was removed under reduced pressure to yield the crude product. This was bulb-to-bulb distilled on Kugelrohr apparatus at 80°-100° C./ca. 1 mm to yield 25.0 g (98%) of methyl 4-hydroxycyclohexanecarboxylate. 1H NMR (CDCl3, 60 MHz) δ 3.85 (s, 1 H); 3.65 (s, 3 H); 2.50-1.20 (m, 10 H).

1. additionwas added
2. customthe bottle was flushed with nitrogen, 2.5 g of 5% rhodium on alumina
3. additionwas added
4. customThe reaction was then flushed with nitrogen
5. filtrationfiltered through diatomaceous earth
6. customto remove the catalyst
7. washThe diatomaceous earth was rinsed with methanol
8. filtrationto filter the catalyst to dryness
9. customthe methanol was removed under reduced pressure
10. additionwas added
11. customThe precipitated alumina and potassium carbonate were removed by filtration through diatomaceous earth
12. washThis was rinsed with ether
13. customthe solvent was removed under reduced pressure
14. customto yield the crude product
15. distillationThis was bulb-to-bulb distilled on Kugelrohr apparatus at 80°-100° C./ca. 1 mm

ORD record

ord-49161d2db6c4437582a87c5c534b593b

Source dataset

uspto-grants-1988_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04748274