[lav]

What is the best way of stopping the reaction of reductive amination, and by which mechanism is it occuring?
I would be very greatful any information... 

[refid]

Reductive amination: the first step is forming the imine, then treating the imine with a reducing agent (NaBh4 or H2 pd/C)

I guess to stop this reaction, is to not add reducing agents

[lav]

that is correct, and what i need is stopping the reaction after few hours...and i am wonderin what is the best way, pH reducing? What is the mechanism?

[Rico]

Hey lav

The best way to stop a reduction with a "hydride" reducing agent such as sodiumborohydride, is to add water. The reducing agent will immediately react with the water instead and the reduction will be stopped.
The mechanism of reductive amination can be seen in this small animation:

http://bcs.whfreeman.com/vollhardtschore4e/cat_010/ch21/21010-01.htm

Rico

[hjn]

In that sense of reductive amination how can i decrease the reaction time if i use sodium cyanoborohidride as a reductive agent and Mpeg in a reaction with a protein. Thanks everyone

[hjn]

I agree with not to add reductive agent this will act a limitant reagent and the reaction will stop in imine formation