1,5-Dibromopentane → HCID 19921918, compound

Reaction equation

[OH:1][C:2]1[CH:12]=[CH:11][C:5]2[C:6](=[O:10])[CH2:7][CH2:8][O:9][C:4]=2[C:3]=1[CH2:13][CH2:14][CH3:15].[Br:16][CH2:17][CH2:18][CH2:19][CH2:20][CH2:21]Br.C(=O)([O-])[O-].[K+].[K+]>CC(=O)CC>[Br:16][CH2:17][CH2:18][CH2:19][CH2:20][CH2:21][O:1][C:2]1[CH:12]=[CH:11][C:5]2[C:6](=[O:10])[CH2:7][CH2:8][O:9][C:4]=2[C:3]=1[CH2:13][CH2:14][CH3:15]

Participants

Procedure

A mixture of 0.413 g (2.00 mmol) of 2,3-dihydro-7-hydroxy-8-propyl-4H-1-benzopyran-4-one, 3.0 g (13.05 mmol) of 1,5-dibromopentane, 1.4 g (10.13 mmol) of anhydrous granular potassium carbonate and 31 mL of 2-butanone was stirred and refluxed for 18 hr. The resulting slurry was filtered with suction and the solids were washed thoroughly with ethyl acetate. The filtrate and washes were combined and concentrated in vacuo and the residue was purified by flash chromatography on 75 g of silica gel, eluting with 4:1 hexane-ethyl acetate giving 0.627 g (88%) of the title compound as a white solid, mp 47°-48° C.