Synthesis of deramciclane labelled with radiocarbon in various positions

Article abstract of DOI:10.1002/(SICI)1099-1344(199712)39:12<1011::AID-JLCR49>3.0.CO;2-Z

[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 sail, 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 an 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%.