137-43-9

Preparation

Bromocyclopentane is synthesized by bromination of cyclopentanol: cyclopentanol is mixed with hydrobromic acid and heated to about 170°C refluxed for 6-8h. Then distilled with water steam, the oil layer is washed with 5% sodium carbonate, then dried, filtered, fractionated and collected 136-139°C fraction is the finished product. Another method is by the reaction of cyclopentanol and phosphorus tribromide: the cyclopentanol is cooled to 0 ℃, add the newly evaporated phosphorus tribromide drop by drop, add it all at 0-5 ℃, stir for 2h, and leave it at room temperature overnight. Add water and stratify, take the oil layer water distillation. Distillate stratification, the oil layer was washed with 10% sodium bicarbonate solution, dried with anhydrous calcium chloride, filtration, filtrate distillation, collect 134-141 ℃ fraction that is bromocyclopentane.

Reactions

Bromocyclopentane is reacted with magnesium turnings in dry tetrahydrofuran making cyclopentyl Grignard reagent, a main precursor in the synthesis of Ketamine.Bromocyclopentane (22.0 g, 0.15 mol) was added to a soln of NaNO2 (18 g, 0.26 mol) in dry DMSO (100 mL) at 15°C and the mixture was stirred at this temperature for 3 h. The mixture was poured into ice water (250 mL) and extracted with petroleum ether (bp 35-37°C; 4 × 50 mL). The combined organic extracts were washed with H2O (4× 50 mL), dried (MgSO4), and concentrated under reduced pressure. The residue was distilled to give Nitrocyclopentane; yield: 9.9 g (58%); bp 62°C/8 Torr; nD/20 1.4538.Synthesis of Nitrocyclopentane

Synthesis Reference(s)

The Journal of Organic Chemistry, 54, p. 1463, 1989 DOI: 10.1021/jo00267a047