Organic Syntheses, CV 3, 692
Submitted by D. W. Andrus
Checked by Nathan L. Drake and Charles M. Eaker.
1. Procedure
The heavy lower layer is separated (Note
2), washed once with a saturated solution of
sodium bicarbonate and once with water, and then dried over
4–5 g. of anhydrous calcium chloride. The crude product is decanted from the
calcium chloride, and the drying agent is rinsed once or twice with a small quantity of
ethyl bromide which is added to the main product. The mixture is distilled under reduced pressure, and the
pentamethylene bromide, which weighs
46–47 g. (
80–82%), is collected at
104–106°/19 mm.
2. Notes
1. The submitter refluxed the mixture for 10 hours, but the checkers obtained equally good yields in 3 hours.
2. The upper aqueous layer contains considerable unchanged
hydrobromic acid. If this layer is distilled, about
150 g. (0.9 mole) of constant-boiling hydrobromic acid (b.p.
123–124°/748 mm.) may be recovered.
3. Discussion
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