Hydrochloric Acid → 6-Bromospiro[2H-1-benzopyran-2,1′-cyclopentan]-4(3H)-one

HRID 2096497Notes

Reaction equation

HRID 2096497 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.[C:12]1(=O)[CH2:16][CH2:15][CH2:14][CH2:13]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:12]1([CH2:16][CH2:15][CH2:14][CH2:13]1)[CH2:9][C:8]2=[O:10]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 8452CyclopentanoneHCID 31268PyrrolidineHCID 959915'-Bromo-2'-hydroxyacetophenone

Product 1

HCID 591678716-Bromospiro[2H-1-benzopyran-2,1′-cyclopentan]-4(3H)-oneYield 110.9%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

A mixture of 1-(5-bromo-2-hydroxy-phenyl)-ethanone (15.8 g, 73.8 mmol), cyclopentanone (12.35 g, 147 mmol) and pyrrolidine (12 mL, 140 mmol) in MeOH (300 mL) was stirred at room temperature overnight. 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-bromospiro[chroman-2,1′-cyclopentan]-4-one (23 g, 100%). 1H-NMR (CDCl3): 1.64 (m, 4H), 1.72 (m, 2H), 2.03 (m, 2H), 2.78 (s, 2H), 6.78 (m, 1H), 7.48 (m, 1H), 7.91 (m, 1H).

Workup

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

Sources & evidence

ORD record
ord-d65905df40ea4b188b4a8fca46baaa0b
Source dataset
uspto-grants-2013_05
Patent number
US08450308B2

Reaction notes

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