Biosynthesis of the Securinega alkaloids. Stereospecificity of hydrogen loss from C-3 of tyrosine

Specimens of (3RS)-[3-3H, 3-14C]-, (3R)-[3-3H, 3-14C]-, and (3S)-[3-3H, 3-14C]-DL-tyrosine have been administered to Securinega suffruticosa to demonstrate that the pro-S hydrogen at C-3 of tyrosine is lost during the biosynthesis of securinine from this amino-acid.