[smsam]

Could you help me with this mechanism, I know that HCl is source of protons and Sn is source of electrons.

So, Sn is going to be oxidized from Sn(2+) to Sn(+4) and nito group is going to be reduced N(+2) to N(-4). 

But, I do not understand how electrons are transferred to the nitrogen


The reaction is

http://s22.postimg.org/vgy9d6i7l/7777777.png

[shalikadm]

Is this what you were looking for ?
http://organicchemistrymessageboard.yuku.com/topic/976#.UiRSnaMclfA

[smsam]

Yes, Thank you so much