Uses
1,3,5-Tribromoadamantane is an brominated impurity of Memantine (M218000), an antiparkinsonian and antispasmodic agent.
Synthesis
Step 1: In a 5L four-necked reaction flask equipped with a condenser, thermometer, and tail gas absorption device, slowly add 108 g of iron powder dropwise to 400 mL of anhydrous bromine for about half an hour. After the dropwise addition was completed, stirring was continued for 30 minutes.
Step 2: Slowly add the remaining bromine dropwise to the reaction flask. After completion of the dropwise addition, the reaction system was heated to 45-50 °C, and then 600 g of adamantane was slowly added. The reaction temperature was raised to 62-65°C to reflux. The reaction lasted for 65 h, during which time samples were taken for GC analysis to monitor feedstock consumption (control experiment 1). The molar ratio of adamantane, anhydrous bromine and iron powder was 1:10.6:0.44.
Step 3: After completion of the reaction, bromine was recovered by distillation. The reaction mixture was poured into ice containing 3.5 L of chloroform, stirred for 10 minutes, and then filtered through a diatomaceous earth pad.
Step 4: The filtrate was washed with saturated aqueous sodium bisulfite to consume excess bromine (note cooling). Use 5 kg of solid sodium bisulfite for washing.
Step 5: The organic layer was washed twice with water, using 3kg of water each time. After washing, the organic layer was concentrated to dryness to give 1.95kg of crude product.
Step 6: The crude product was dissolved in 13L of methanol and heated until dissolved. 65g of activated carbon was added and filtered hot. The filtrate was crystallized with stirring (cooled with ice) and filtered to give 1.19kg of product. The mother liquor was concentrated to about one-third of the original volume, crystallized again with stirring, and filtered to obtain 250g of white fine powder.
References
[1] Chemische Berichte, 1960, vol. 93, p. 1366 - 1371
[2] Journal of Organic Chemistry, 2004, vol. 69, # 4, p. 1010 - 1019
[3] Chemistry - An Asian Journal, 2011, vol. 6, # 6, p. 1450 - 1455
[4] Journal of Organic Chemistry, 2014, vol. 79, # 14, p. 6738 - 6742
[5] Patent: CN104628526, 2016, B. Location in patent: Paragraph 0069-0075
