Hydrochloric Acid → 6-Bromo-3'-methylspiro[chroman-2,1'-cyclopentan]-4-one

HRID 2096556Notes

Reaction equation

HRID 2096556 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([OH:11])=[C:6]([C:8](=[O:10])[CH3:9])[CH:7]=1.[CH3:12][CH:13]1[CH2:17][CH2:16][C:15](=O)[CH2:14]1.N1CCCC1.Cl>CO.O>[Br:1][C:2]1[CH:7]=[C:6]2[C:5](=[CH:4][CH:3]=1)[O:11][C:15]1([CH2:16][CH2:17][CH:13]([CH3:12])[CH2:14]1)[CH2:9][C:8]2=[O:10]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 156503-MethylcyclopentanoneHCID 31268PyrrolidineHCID 959915'-Bromo-2'-hydroxyacetophenone

Product 1

HCID 584244946-Bromo-3'-methylspiro[chroman-2,1'-cyclopentan]-4-one

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

A mixture of 1-(5-bromo-2-hydroxy-phenyl)-ethanone (2.193 g, 10.2 mmol), 3-methylcyclopentanone (2 g, 20.4 mmol) and pyrrolidine (1.67 mL, 19.43 mmol) in MeOH (42 mL) was stirred at room temperature overnight, followed by reflux for 2 days. The mixture was concentrated in vacuo to give the residue, which was added water and HCl (36%) until pH=1. The mixture was extracted with EtOAc and then the organic layer was concentrated to give 6-bromo-3′-methylspiro[chroman-2,1′-cyclopentan]-4-one, which was purified by chromatography (PE:EA 300:1-200:1) (2.3 g, 76%). 1H NMR (CDCl3): 7.94 (d, 1H), 7.52-7.49 (m, 1H), 6.83-6.79 (m, 1H), 2.79 (m, 2H), 2.39-2.22 (m, 0.5H), 2.21-1.95 (m, 3H), 1.91-1.75 (m, 1H), 1.67-1.57 (m, 1H), 1.51-1.41 (m, 0.5H), 1.31-1.15 (m, 1H), 1.08-0.98 (m, 3H).

Workup

  1. temperatureby reflux for 2 days
  2. concentrationThe mixture was concentrated in vacuo
  3. customto give the residue, which
  4. extractionThe mixture was extracted with EtOAc
  5. concentrationthe organic layer was concentrated

Sources & evidence

ORD record
ord-0de45e6c92054f0a8a1ecfbb5d2a1a2a
Source dataset
uspto-grants-2013_05
Patent number
US08450308B2

Reaction notes

Loading…