[Xera]

Hey, I need help to understand TBTU as a coupling reagent. I am currently trying to draw it in Chemdraw but there seems to be two different ones?? I am not computing it and would love for someone to explain why there is this misunderstanding. I have linked the two different 'structures' would be amazing if anyone could enlighten me. Thanks a lot!

[Hunter2]

It is the same compound only a different mesomer form.

See in the link below

https://media.springernature.com/full/springer-static/image/art%3A10.1007%2Fs11164-011-0375-y/MediaObjects/11164_2011_375_Sch2_HTML.gif