Pifazin, Pierrel ,Italy ,1983
A solution of 45 mmols of 1-bromo-3,7,11-trimethyl-2,6,10-dodecatriene (obtained from synthetic farnesol, commercially available and containing four isomers) in 10 ml of benzene was added dropwise at 0°C to a stirred solution of 45 mmols of piperonylpiperazine in 60 ml of benzene containing 5 g of triethylamine. The mixture was stirred for 2 hours and then the precipitated triethylammonium bromide was filtered off. The benzene solution was washed first with water and then with K2CO3 solution and finally dried (K2CO3). Removal of benzene under reduced pressure gave a crude oily residue which was dissolved in acetone and treated at 5°C to 8°C with a slight excess of 37% HCl solution. The precipitated hydrochloride was filtered, washed with acetone and with absolute ethanol. The corresponding base was purified on a silica gel column and the purity of all fractions was checked by thin layer chromatography and gas liquid chromatography. Thin layer chromatography on silica gel gave three spots in the solvent system ethylacetate-petrol ether 1:1. Gas liquid chromatography showed three peaks indicating the presence of four possible isomers. The pure product was a colorless oil.
