Propanal → HCID 19889219, compound

A mixture of zinc (4.25 g, 0.26 mol, granular), a small crystal of iodine and THF (200 ml, freshly distilled over LAH) was refluxed with stirring under a nitrogen atmosphere for 30 min. A portion of the solution (20 ml) of t-butyl α-bromoacetate (35.2 ml, 0.22 mol) and propionaldehyde (10.4 ml, 0.152 mol in THF, 200 ml, freshly distilled over LAH) was added to the above mixture. Within a few minutes the solution became cloudy and the iodine color disappeared. The remainder of the solution was added to the zinc during 30 min, after which the reactants were stirred and heated under reflux for 1 h. The cooled solution was poured into 0.1 N HCL (800 ml) and the pH was adjusted to ~2 with 2 N HCL. The excess of zinc was filtered off and the crude products were extracted into ethyl acetate (3×200 ml). The organic extracts were combined and washed with 8% NaHCO3 (2×200 ml), with water (2×200 ml) and dried over anhydrous MgSO4. The ethyl acetate was evaporated off under reduced pressure to give the crude ester which was purified by distillation, bp 71°-73° C./15 mm, to give colorless liquid (21.3 g, 54.5%). ir (neat) νmax : 3460 (--OH) and 1730 cm-1 (C=O of ester), 1Hmr (CDCl3) δ: 093 (3H, t), 1.23-1.83 (2H, m), 1.43 (9H, s), 2.32 (2H, d), 3.67 (H, s, OH) and 3.73 ppm (H, m).

1. distillationa small crystal of iodine and THF (200 ml, freshly distilled over LAH)
2. temperaturewas refluxed
3. additionwas added to the above mixture
4. waitWithin a few minutes the solution became
5. stirringafter which the reactants were stirred
6. temperatureheated
7. temperatureunder reflux for 1 h
8. additionThe cooled solution was poured into 0.1 N HCL (800 ml)
9. filtrationThe excess of zinc was filtered off
10. extractionthe crude products were extracted into ethyl acetate (3×200 ml)
11. washwashed with 8% NaHCO3 (2×200 ml), with water (2×200 ml)
12. dry with materialdried over anhydrous MgSO4
13. customThe ethyl acetate was evaporated off under reduced pressure
14. customto give the crude ester which
15. distillationwas purified by distillation, bp 71°-73° C./15 mm

ORD record

ord-7875a197fd2d4a3c9bb5b16b22521d86

Source dataset

uspto-grants-1983_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04378314