Route to tritium labelled 11-methyl prostaglandins

Labelled 11-methyl prostaglandins have been prepared via the catalytic tritium reduction of 11-iodomethyl intermediates. Two examples are reported for the preparation of such 11-iodomethyl precursors in which the desired lower side chain is attached in non-radioactive steps. Subsequent tritium hydrogenolysis of the 11-iodomethyl lactones followed by addition of the delta 5 cis-double bond yielded prostaglandins having specific activities of 10-15 Ci/mmol