Ph-Ch2-COH + NH2-CO-NH-NH2 ---> ?

The answer is:
Ph-CH=N-NH-CO-NH2

MY question is, why can't the answer also be:
Ph-CH2-CH=N-CO-NH-NH2 ???

Is there a special rule where specific amine end has to be added onto the carbonyl carbon? Please explain!

Ok, the reason is the OH on COOH and the NH2 on CONH2 are both quite unreactive. They rarely react and if they do it will require a high temp.
The double bonded oxygen on a COOH is more reactive than the OH on it.
Rule of thumb: Don't attack with those two things I previously mentioned because they are very stable as is, which means they won't react.
I hope that helps.
GOOD LUCK

Ok, the reason is the OH on COOH and the NH2 on CONH2 are both quite unreactive. They rarely react and if they do it will require a high temp.
The double bonded oxygen on a COOH is more reactive than the OH on it.
Rule of thumb: Don't attack with those two things I previously mentioned because they are very stable as is, which means they won't react.
I hope that helps.
GOOD LUCK

Hi doc, i don't understand why it is not reactive, is it because it is next to CO group which withdrawing electron of N?
Thank you.

To the previous poster: Resonance makes the C--OH into a C==OH +charge Which is a very bad nucleophile and will not attack the electrophile.

To the previous poster: Resonance makes the C--OH into a C==OH +charge Which is a very bad nucleophile and will not attack the electrophile.

I understand now. Thank you so much