Water → Tricyclene

Participants

Reaction Conditions

Reaction Steps

53 ml of concentrated sulfuric acid is added to a solution of 95 ml of benzylethanolamine in 690 ml of toluene. The suspension that is produced is heated to boiling for 2 hours. The water that is produced in this case (14 ml) is separated with the aid of a water separator. After cooling to 20° C., the reaction mixture is mixed with 1300 ml of water and absorptively precipitated for 10 minutes, and the organic phase is separated. Then, the aqueous phase is quickly added to a solution of 92.2 g of NaOH in 95 ml of water that is introduced in a second reaction vessel. The reaction mixture is heated to boiling. 880 g of water-N-benzylaziridine emulsion in a third reaction vessel is distilled off through a distillation bridge. The emulsion is mixed with 880 ml of ethanol and heated to 60° C. To this end, a solution of 38.0 g of p-TsOH in 19 ml of water is added within 8 hours via a metering pump. After the addition is completed, it is refluxed for two hours. Then, the reaction mixture is mixed with a solution of 12.0 g of NaOH in 20 ml of water. The precipitated product is filtered and recrystallized from 600 mlof 2:1 ethanol-THF mixture. The tetrabenzylcyclene (53 g) thus obtained is dissolved in 500 ml of isopropanol and hydrogenated with 10 g of Pd/C (10%) at 80° C. and 20 bar of H2 pressure. After the catalyst is filtered off, the reaction solution is concentrated by evaporation, andthe product is recrystallized from toluene. 15.9 g (55% of theory) of cyclene is obtained as colorless crystals. Melting point 110°-112° C.

Provenance & Evidence