The reaction between 5'-deoxypyridoxal and
glycine in D
2O buffered at pD 7.0 does not result in si
gnificant formation of the expected products of pyridoxal-catalyzed transamination or deuterium exchan
ge of the
ges/
gifchars/alpha.
gif" BORDER=0>-amino protons of
glycine, but rather
gives a
quantitative yield of the two diastereomeric products of the formal Claisen-type addition of
glycine to 5'-deoxypyridoxal. The unexpected extensive formation of these products reflects the extraordinary selectivity of the 5'-deoxypyridoxal-stabilized
glycine enolate toward addition to the carbonyl
group of 5'-deoxypyridoxal in the protic solvent water.