Synthesis
The general procedure for the synthesis of 1-adamantyl bromomethyl ketone from 1-adamantyl methyl ketone was as follows: 1-adamantyl methyl ketone (1.0 equiv) was reacted with N-bromosuccinimide (NBS, 1.1 equiv) in a mixed solvent of petroleum ether and methanol at reflux for 2 h at 333 K. The reaction was carried out at 333 K for 2 h. The reaction was completed by filtration and purification with ethanol. Upon completion of the reaction, the resulting precipitate of 1-adamantyl bromomethyl ketone (1) was collected by filtration and purified by recrystallization with ethanol. Subsequently, the purified 1-adamantyl bromomethyl ketone (1) (0.51 g, 0.002 mol) was reacted with the corresponding carboxylic acid (1.5 equiv) in the presence of potassium carbonate (1.2 equiv) with stirring at room temperature in DMF (8 mL) for about 3 hours. The reaction process was monitored by thin layer chromatography (TLC). At the end of the reaction, the reaction mixture was slowly poured into ice-cooled water with continuous stirring for 10 min. The resulting solid product was separated by filtration, washed sequentially with distilled water, dried and further purified using acetone recrystallization [20]. All 1-adamantyl bromomethyl ketone derivatives were obtained in high yields and high purity. In addition, single crystal samples suitable for single crystal X-ray diffraction analysis were successfully obtained by incubation from different solvent systems. The chemical structures of the compounds were corroborated by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The crystal structures of all compounds except compounds 2m and 2q were determined by single crystal X-ray diffraction analysis.
Purification Methods
Dissolve the ketone in Et2O, wash it with H2O, dry (MgSO4), evaporate and crystallise the residue from small volumes of MeOH. LACHRYMATORY. [Stetter & Rauscher Chem Ber 93 2054 1960.]
References
[1] Molecules, 2015, vol. 20, # 10, p. 18827 - 18846
[2] Patent: WO2016/131380, 2016, A1. Location in patent: Paragraph 358; 359
[3] Russian Journal of Organic Chemistry, 2015, vol. 51, # 2, p. 184 - 187
[4] Zh. Org. Khim., 2015, vol. 51, # 2, p. 196 - 199
[5] Chemische Berichte, 1960, vol. 93, p. 2054 - 2057
