HCID 9959542, compound → HCID 11050014, compound

Participants

Reaction Conditions

Reaction Steps

A 4000 ml round-bottom flask is initially charged with 2535 g (1.67 mol) of a 37.2% by weight solution of [(2E,4E)-3-methyl-5-(2,6,6-trimethylcyclohexen-1-yl)penta-2,4-dienyl]triphenylphosphonium hydrogensulfate in methanol under nitrogen, which is alkalized by addition of 111.30 g (0.618 mol) of a 30% by weight sodium methoxide solution in methanol, and the precipitated sodium sulfate is filtered off. The filtrate is pumped through a flow reactor heated to 145° C. with an exactly fixed residence time of 25 min. Subsequently, the solvent is distilled off, the residue is taken up in isopropanol and acidified with sulfuric acid to a pH of 0.3, and the unisomerized [(2E,4E)-3-methyl-5-(2,6,6-trimethylcyclohexen-1-yl)penta-2,4-dienyl]triphenylphosphonium salt of the general formula 2 is crystallized by adding 823 g of heptane and cooling to −10° C. After the crystals have been filtered off, 1648 g of an 11.2% by weight solution of [(2Z,4E)-3-methyl-5-(2,6,6-trimethylcyclohexen-1-yl)penta-2,4-dienyl]triphenylphosphonium-hydrogensulfate (0.327 mol) are obtained in a purity of 95% and a yield of 20%.

Provenance & Evidence