Syntheses with stable isotopes: DL‐valine‐¹³C₃

Abstract

Abstract The synthesis of DL‐2‐amino‐3‐methyl‐ 13 C‐butanoic‐3,4‐ 13 C 3 acid (DL‐valine‐ 13 C 3 ) is described. Acetonitrile‐2‐ 13 C was converted to 2‐methyl‐ 13 C‐2‐thiazoline, which was dialkylated with methyl‐ 13 C iodide to give 2‐(isopropyl‐ 13 C 3 )‐2‐thiazoline. Subsequent reduction and hydrolysis of the isopropylthiazoline afforded 2‐methyl‐ 13 C‐propanal‐2,3‐ 13 C 2 , which was isolated as the bisulfite addition product. A modified Strecker synthesis with the bisulfite compound gave DL‐valine‐ 13 C 3 in good overall yield.