Syntheses of [11C]methyl esters of prostaglandins D2 and E2

Prostaglandins (PG) are endogenous compounds that have been extensively studied by various techniques. In this paper, the syntheses of methyl esters of PGD2 and PGE2, labelled with 11C for PET investigations, are reported. The prostaglandin was esterified via its carboxylate anion, with [11C]methyl iodide as alkylating reagent, in a dimethyl sulphoxide-dimethylformamide mixture. To minimize the base-catalysed degradations, the carboxylate anion was generated in situ by use of tetramethylpiperidine. The radiochemical yield, including purification, was 70%, with a total synthesis time of 20-25 min counted from the end of the [11C]methyl iodide synthesis.