Fast hydrazone reactants: electronic and acid/base effects strongly influence rate at biological pH.
Kinetics studies with structurally varied aldehydes and ketones in aqueous buffer at pH 7.4 reveal that carbonyl compounds with neighboring acid/base groups form hydrazones at accelerated rates. Similarly, tests of a hydrazine with a neighboring carboxylic acid group show that it also reacts at an accelerated rate. Rate constants for the fastest carbonyl/hydrazine combinations are 2-20 M(-1) s(-1), which is faster than recent strain-promoted cycloaddition reactions.
Department of Chemistry, Stanford University , Stanford, California 94305-5080, United States.
Eric T
ET
Kool
Do-Hyoung
DH
Park
Pete
P
Crisalli
D000447:Aldehydes / Q000737:chemistry; D002021:Buffers; D006835:Hydrazones / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007659:Ketones / Q000737:chemistry; D007700:Kinetics
D000447:Aldehydes; D002021:Buffers; D006835:Hydrazones; D007659:Ketones