Toluene → HCID 15143267, compound

Participants

Reaction Steps

To a three-necked round-bottomed flask, equipped with a Dean-Stark trap (20 mL), a reflux condenser, a thermometer and a magnetic stir bar, was placed 2,2-cyclohexene-dimethanol 1 (15.78 g, 111 mmol) and 400 mL of toluene under an atmosphere of N2. The mixture was brought to reflux and maintained at reflux temperature for 2 hours to azeotropically remove any moisture. About 100 mL (5×20 mL) of azeotropic mixture was collected in the Dean-Stark trap. The mixture was then allowed to slowly cool to room temperature and 0.3 g of anhydrous para-toluenesulfonic acid (PTSA) was added, followed by dropwise addition of tetraethylorthocarbonate (TEOC, 11.7 mL, 56 mmol). The resulting mixture was brought to reflux to azeotropically remove ethanol generated during the reaction. The azeotropic mixture was shaken with salt water to determine the amount (volume) of ethanol collected. The reaction was monitored by GC (5 min at 105° C., a 20° C./min rise to 225° C.) and/or by TLC (silica gel, 15% ether/hexanes). After a total of 160 m L of azeotropic mixture (12.3 mL of ethanol) was collected, the reaction mixture was allowed to reflux for an additional 2 hours and then allowed to stir at 102° C. overnight. The reaction mixture was allowed to slowly cool to room temperature and then neutralized by the addition of 1 mL of triethylamine. The resulting mixture was allowed to stir at room temperature for an additional 30 min, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give a light yellowish solid. The crude material was then purified by flash chromatography (silica gel, 15-25% ether/hexanes) or by recrystallization from refluxing ethyl ether/hexanes (v/v 1:1). The desired product 8,10,19,20-tetraoxatrispiro[5.2.2.5.2.2]henicosa-2,14-diene 2 (DCH) was obtained as white crystals in 80% yield. Mp (DSC) 118° C.; 1H-NMR (CDCl3, 300 MHz) a 126.20, 124.29, 114.82, 70.21, 30.62, 26.56, 21.42; IR (KBr pellet) (cm−1) 3020, 2920, 2850, 1630, 1440, 1365, 1250, 1225, 1190, 1100, 1025, 1000, 935, 920, 650; Anal. Calcd for C16H26O5: C, 69.84; H, 8.27; Found: C, 69.68; H, 8.42.

Provenance & Evidence