Methodes de Synthese de l'Acide Agarique Racemique Marque au ¹⁴C (acide α‐cetyl citrique (carboxyle‐1 ¹⁴C) OU acide hydroxy‐2 nonadecanetricarboxylique‐1,2 (carboxyle ¹⁴CO)‐3)

Racemic [3‐carboxyl ¹⁴C] agaric acid triethyl ester was prepared in low yield by treatment of ethyl 2‐ethoxalyl octadecanoate 2 with either ethyl lithioacetate or ethyl bromoacetate, zinc and methyl borate. In another approach, lithio ethynyltrimethylsilane 6 was condensed with 2 to give 7 which, with dicyclohexylborane 8, gave the vinyl borane 9; the latter, by hydrogen peroxide oxidation followed by reaction of diazomethane gave the mixed ester 11 in low yield. [3‐carboxyl ¹⁴C] Agaric acid, specific activity 57 mCi/mmol, was obtained from 5 or 11 by saponification with lithium hydroxide in 1,2‐dimethoxyethane. The best overall yield from ethyl [1‐¹⁴C] stearate was 18%.