Hydrogen Bromide → 2-Bromo-1-(5-methyloxolan-2-yl)ethan-1-one
Reaction equation
[CH3:1][CH:2]1[O:6][CH:5]([C:7]([OH:9])=O)[CH2:4][CH2:3]1.[C:10](Cl)(=O)C(Cl)=O.[BrH:16]>ClCCl.CN(C)C=O>[Br:16][CH2:10][C:7]([CH:5]1[CH2:4][CH2:3][CH:2]([CH3:1])[O:6]1)=[O:9]Participants
Conditions
- Temperature
- 0 °C
Procedure
A solution of 5-methyl-2-tetrahydrofuroic acid (1.80g, 13.85mmol) in dichloromethane (25ml) was treated with oxalyl chloride (2.4ml, 27.51mmol) in the presence of dimethylformamide (3 drops). After stirring for 1.25h, the solvent was evaporated in vacuo. The residue was re-dissolved in dichloromethane and concentrated again. Excess diazomethane was then bubbled through a solution of the resulting acid chloride in dichloromethane (30ml) at 0° C. When the addition was complete, the mixture was stirred for 10 min. at 0° C. and then treated with 48% aqueous hydrogen bromide (2.6ml, 15.41mmol). The mixture was stirred for 15 min. at room temperature, washed with water (x2), dried and concentrated in vacuo to yield the crude title compound as a brown oil (1.67g, 58%); vmax (CH2Cl2) 1735, 1387 and 1086cm-1 ; δH (CDCl3, 90MHz) 1.33 (3H, d, J 6.0Hz), 1.48 (1H, m), 1.90-2.35 (3H, m), 4.10 (1H, m), 4.25 (2H, s) and 4.48 (1H, m).
Workup
- customthe solvent was evaporated in vacuo
- dissolutionThe residue was re-dissolved in dichloromethane
- concentrationconcentrated again
- customExcess diazomethane was then bubbled through a solution of the resulting acid chloride in dichloromethane (30ml) at 0° C
- additionWhen the addition
- stirringThe mixture was stirred for 15 min. at room temperature
- washwashed with water (x2)
- customdried
- concentrationconcentrated in vacuo
Sources & evidence
- ORD record
- ord-4c025b16b2814f329fe79de39f173685
- Source dataset
- uspto-grants-2000_02
- Patent number
- US06020329
Reaction notes
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