BOC deprotection by TFA form a salt, i.e
( R-CH2-NH-CH2-CH2-NH3+-OOCCF3 ) . What would be the proton NMR peak for -NH3+ portion of this salt ? or IR spectra ? Does any reference article ?
To confirm the BOC is removed, a TLC will be the easiest.
The NMR will also show the removal of the t-butyl peak ~1.5ppm. The NH3+ is difficult to see and not reliable. You could run 19F NMR to see the TFA salt
Thank you @Eugene Yang
I have done BOC-deprotection by TFA, and reaction was monitored by TLC, even by NMR but ATR does not showing any -NH2 peak. Eventually I pass ammonia gas to remove TFA-salt but unfortunate ATR is not showing any primary amine (-NH2) peak yet.
the NH2 peak is difficult to see too as well as it can exchange proton with water if present. Same as with OH
" Though it is difficult to see -NH2 NMR peak, in IR Primary amines (RNH2) display 2 bands, near 3500 and 3400 cm–1 which are weaker and sharper than OH." So I am failed to get such kind of band of RNH2 after BOC deprotection by TFA.
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