SYNTHESIS OF 1-CARBOXY-N,N,N-TRI-[METHYL-C-14] METHANAMINIUM CHLORIDE(BETAINE[METHYL-C-14]HYDROCHLORIDE)

Methyl bromoacetate was reacted with trimethylamine-[C-14] dissolved i n methanol, forming the methyl ester of [C-14] labeled betaine hydrobr omide. The methyl ester was hydrolyzed in an alkaline medium to (carbo xymethyl)trimethylammonium hydroxide inner salt, and then transformed into the hydrochloride by treatment with an equivalent amount of hydro chloric acid, yielding high purity material with a specific activity o f 19.2 mu Ci/mmol and overall yield of 81.7%.