For Purell Ketone Chemical Synthesis,

Terprenone is a new cytoprotective antiulcer agents. In this article, terprenone was obtained from coupling of (2E,6E)-8-bromo-3,7-dimethylocta-2,6-dienyl acetate and geranyl sulfone, desulfonylation with lithium and amine, bromination with PBr3 in anhydrous ether, alkylation with anion of ethyl acetoacetate, decarboxylation by aqueous sodium hydroxide. Geranyl sulfone was obtained in this way: treatment of trans-geraniol in anhydrous ether with PBr3 afforded trans-geranyl bromide, treatment of trans-geranyl bromide with sodium sulfinate in anhydrous DMF afforded geranyl sulfone. And (2E,6E)-8-bromo-3,7-dimethylocta-2,6-dienyl acetate was obtained in this way: stereoselective oxidation of geranyl acetate with selenium dioxide gave rise to corresponding aldehyde, then reduction with sodium borohydride afforded allylic alcohol, and treatment of allylic alcohol in anhydrous ether with PBr3 afforded (2E,6E)-8-bromo-3,7-dimethylocta-2,6-dienyl acetate.TLC, GC, HPLC and NMR were employed as the analysis methods. Trans-geranyl bromide was prepared with geraniol and phosphorous tribromide at -10~0℃ for 30min in a yield of 89%, the mole ratio of geraniol to phosphorous tribromide is 1:0.4. Treatment of geranyl bromide with sodium sulfinate at ambient temperature for an hour afford geranyl sulfone in a yield of 92%, the mole ratio of geranyl bromide to sodium sulfinate is 1:1.1. Stereoselective oxidation of geranyl acetate at 25℃ for 4 hours afford corresponding aldehyde in a yield of 80%, the mole ratio of selenium dioxide to geranyl acetate to peroxide is 1:2:4. Reduction of aldehyde at -10℃ for 45min afford allylic alcohol in a yield of 90%, the mole ratio of allylic alcohol to sodium borohydride is 2:1. Treatment of allylic alcohol with PBr3 at -10~0℃ for 2 hours afford (2E,6E)-8-bromo-3,7-dimethylocta-2,6-dienyl acetate in a yield of 78%, the mole ratio of allylic alcohol to phosphorous tribromide is 1:0.4. Coupling of (2E,6E)-8-bromo-3,7-dimethylocta-2,6-dienyl acetate and geranyl sulfone with alkali at -25℃ for 30min afford alkylation in a yield of 91%, the mole ratio of geranyl sulfone to allylic bromide to alkali is 1:1.1:2. Desulfonylation of alkylation with lithium and amine at -75℃ for 30min afford geanylgeraniol in a yieldof 26%, the mole ratio of alkylation to lithium to amine is 1:20:80. All-trans-geranylgeranyl bromide was obtained from bromination of geranylgeraniol at -10~0℃ for 4 hours in a yield of 93%, the mole ratio of geranylgeraniol to phosphorous tribromide is 1:2. Teprenone was synthesized by alkylation of geranygeranyl bromide and ethyl acetoacetate at ambient temperature for 10 hours and decarboxylation with aqueous sodium hydroxide at 60℃ for 4 hours, the yield is 20%.