Hydrochloric Acid → 2,3,4,5-Tetrahydro-1-benzoxepin-5-one

To a solution of phenol (3.16 g, 33.6 mmol) in acetonitrile, was added ethyl 4-bromobutyrate (4.8 ml, 33.6 mmol), potassium carbonate (4.64 g, 33.6 mmol) and tetrabutylammonium iodide (370 mg, 1 mmol). The reaction mixture was stirred vigorously and heated to reflux for 2 days before being cooled, filtered, dried (MgSO4) and concentrated in-vacuo to yield 4-phenoxy-butyric acid ethyl ester. 4-Phenoxy-butyric acid ethyl ester was hydrolyzed to its corresponding carboxylic acid using sodium hydroxide mediated hydrolysis to yield 4-phenoxy-butyric acid. To a solution of 4-phenoxy-butyric acid (7.67 g, 29.6 mmol) in anhydrous dichloromethane was added oxalyl chloride (4.4 ml, 50.3 mmol) and one drop of dimethyl formamide and the reaction mixture stirred at room temperature for 30 minutes. Reaction mixture was concentrated in-vacuo and the residue dissolved in 1,2-dichloroethane (90 ml). This solution was added drop wise to a suspension of aluminum trichloride (4.73 g, 35. 5 mmol) in 1,2-dichloroethane (50 ml) at 0° C. Reaction mixture was left stirring in ice bath which rose to room temperature overnight. The reaction mixture was poured over conc. hydrochloric acid (30 ml) stirred into 10 0 g ice, and then stirred for a further 90 minutes until the ice fully melted. The aqueous phase was washed with dichloromethane 3 times, before the organics were combined, dried (Na2SO4) and concentrated in-vacuo. Purification by triturating with diethylether gave 3,4-dihydro-2H-benzo[b]oxepin-5-one.

1. customReaction mixture
2. concentrationwas concentrated in-vacuo
3. dissolutionthe residue dissolved in 1,2-dichloroethane (90 ml)
4. additionThis solution was added drop
5. customReaction mixture
6. waitwas left
7. stirringstirring in ice bath which
8. waitrose to room temperature overnight
9. washThe aqueous phase was washed with dichloromethane 3 times
10. dry with materialdried (Na2SO4)
11. concentrationconcentrated in-vacuo
12. customPurification
13. customby triturating with diethylether

ORDレコード

ord-6f1332475d5546178f77bbdfaff82bec

出典データセット

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US08846762B2