Synthesis of Deramciclane labelled with radiocarbon in various positions

Abstract

[U‐14C]Bromobenzene, prepared from [14C]barium carbonate according to literature procedures, was transformed (Li/diethylether) into [14C]phenyllithium which was condensed with camphor giving rise to [U‐14C‐phenyl]borneol: 2. The latter, after conversion into its sodium salt, was reacted with dimethylaminoethyl chloride to give [14C‐Ar]Deramciclane, which was isolated as the fumarate salt. This 8 step synthesis from [14C]BaCO3 gave an overall yield of 12%. [1‐14C]Sodium acetate, through a standard 5 step literature procedure, was converted to N,N‐dimethylaminoethyl‐1‐14C chloride 5 which was condensed with the sodium derivative of 2‐phenylborneol giving rise to [1‐14C‐side chain]Deramciclane, again isolated as the fumarate. This 6 step synthesis from [14C]BaCO3 gave overall yield of 8%. The specific radioactivities from the two syntheses were respectively 40 mCi/mmol and 21 mCi/mmol; chemical and radiochemical purities were better than 98%. © 1997 John Wiley & Sons, Ltd.