[kangbear50]

Hi everyone, I have done the experiment as shown in the attachment yesterday, and at the end, I was told to use Brady's reagent to perform confirmation test, and it produced yellow-orange precipitate with Schiff base, no precipitate with isoquinoline. As far as I understand, Brady's reagent is used to detect aldehyde and ketone, but why there was precipitate with Schiff base?

[discodermolide]

Probably because the imine hydrolysed back to the aldehyde, so perhaps the cyclisation did not work?

[kangbear50]

Probably because the imine hydrolysed back to the aldehyde, so perhaps the cyclisation did not work?

That would make a bit sense, cause I forgot to mention that I put 50% aqueous ethanol into both before Brady's reagent, so the ethanol made the Schiff base underwent hydrolysis, and produce yellow ppt?