The labelled juvenoid 2-(4-(2-(ethoxycarbamatoethoxy) (benzene-U-C-14)
benzyl)-1-cyclohexanone ethylene acetal (8) (W 328) was prepared star
ting from p-hydroxy(ring-U-C-14) benzoic acid (1) by a seven step synt
hesis in 11% overall yield. The reaction conditions previously reporte
d for the ''cold'' synthesis of the W 328 (B) were modified to suit th
e small scale preparation.