An improved synthesis of isopentenyl pyrophosphate.

1. Isopentenol was converted into isopentenyl phosphate with phosphoryl chloride in ether containing pyridine. 2. The isopentenyl phosphate reacted in 2-methylpropan-2-ol-water with morpholine and dicyclohexylcarbodi-imide to give isopentenyl phosphoromorpholidate. 3. The isopentenyl phosphoromorpholidate, with inorganic phosphate in pyridine containing tributylamine, gave isopentenyl pyrophosphate. The yield of pyrophosphate from monophosphate was 80-85% and the yield of pyrophosphate from isopentenol 40-60%. [1-(14)C]-Isopentenyl pyrophosphate was prepared by this method. 4. The yield of isopentenyl pyrophosphate from isopentenyl phosphate was substantially improved, in comparison with the yields obtained by published methods via the phosphoramidate, by the use of the phosphoromorpholidate.