Hydrochloric Acid → Methyl 5-oxohexanoate

Calix[4]pyrrole meso-monoester 3. 4-Acetylbutyric acid (3.8 g, 29 mmol) was dissolved in methanol (50 mL) in a 100 mL round bottomed flask with magnetic stirring. Concentrated hydrochloric acid (1 mL, 37%) was added and the mixture heated at reflux for 12 hr. The solvent was then removed in vacuo and the residue redissolved in dichloromethane (50 mL). The solution was then washed with saturated NaHCO3 (aq) solution (2×50 mL) and then brine (1×100 mL). The organic layer was separated and then dried over MgSO4 and reduced in vacuo to give the methyl ester, methyl-4-acetylbutyrate, as a yellow oil (3.5 g, 24.3 mmol) corresponding to a yield of 84%. 1H NMR (CDCl3) 3.64 (s, 3, OCH3), 2.49 (t, J=7.2 Hz, 2, CH2), 2.32 (t, J=7.2 Hz, 2, CH2), 2.12 (s, 3, CH3), 1.86 (m, 2, CH2). 13C NMR (CDCl3) 207.0, 172.8, 50.7, 41.7, 32.3, 29.1, 18.25. Cl MS m/z @145 (MH+)

1. temperaturethe mixture heated
2. temperatureat reflux for 12 hr
3. customThe solvent was then removed in vacuo
4. dissolutionthe residue redissolved in dichloromethane (50 mL)
5. washThe solution was then washed with saturated NaHCO3 (aq) solution (2×50 mL)
6. customThe organic layer was separated
7. dry with materialdried over MgSO4

ORD record

ord-33feaa73ff684801ace48d9118844052

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06262257B1