Methyl 1-benzyl-5-oxopyrrolidine-3-carboxylate → Methyl 1-benzylpyrrolidine-3-carboxylate

A solution of (±) methyl 1-benzyl-2-oxo-4-pyrrolidylcarboxylate (D16, 35.4 g, 0.18 mole) in dry THF (135 ml) was added dropwise over 30 mins to 1 M borane-THF solution (228 ml, 0.23 mole) at 0° C. under nitrogen, and when addition was complete the solution was heated under reflux for 1 h. The solution was cooled to room temperature, then treated dropwise with 8% hydrogen chloride/methanol (114 ml, 0.25 mole HCl) and stirred for 18 h, followed by 3 h at reflux. The mixture was then concentrated in vacuo and the residue treated with water (40 ml), washed with ether (2×50 ml), basified with 40% sodium hydroxide solution, saturated with potassium carbonate and extracted with ether (3×70 ml). The combined extracts were dried (Na2SO4) and concentrated in vacuo to leave a yellow oil, which was purified by distillation (b.p. 146° C./0.7 mmHg) to give the title compound (D17) as a colorless oil (19.8 g, 50%).

1. additionwhen addition
2. temperaturewas heated
3. temperatureunder reflux for 1 h
4. waitfollowed by 3 h
5. temperatureat reflux
6. concentrationThe mixture was then concentrated in vacuo
7. additionthe residue treated with water (40 ml)
8. washwashed with ether (2×50 ml)
9. extractionextracted with ether (3×70 ml)
10. dry with materialThe combined extracts were dried (Na2SO4)
11. concentrationconcentrated in vacuo
12. customto leave a yellow oil, which
13. distillationwas purified by distillation (b.p. 146° C./0.7 mmHg)

ORD record

ord-ee29b27a28a1430295977e98d86b7b16

Source dataset

uspto-grants-1992_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05110828