An example of an amine containing drug is Procaine which contains 2 amine groups.When HCl is added to procaine I think the tertiary amine is protonated as it has more electrons and the benzene amine is delocalised by resonance with the ring so is less available for proton bonding but how can I distinguish between the protonated tertiary amine(NH+) and the protonated primary amine(NH3+) in a HNMR or CNMR spectra for procaine? Are there any other distinguishable chemical shifts or splitting patterns in hnmr or cnmr spectra for NH+ or NH3+ protons(or carbons attched to them)? Does the Cl- have any impact? Very limited knowledge of nmr so detailed explanations please!© BrainMass Inc. brainmass.com June 3, 2020, 11:43 pm ad1c9bdddf
I am a doctor of organic chemistry and have dealt with amines and ammonium fragments a lot. Amines are a real difficulty when it comes to NMR and the peaks that result in proton NMRs are usually extremly broad. In fact, you would be lucky to see them in a lot of instances because they become so broad they disappear into the baseline and you see nothing! This is primarily due to hydrogen bonding between the compound and the solvent and quadrupolar effects (this is an advanced concept and not really delved into at degree level). In summary, if you see them, free alkyl amines tend to come in the proton NMR between 0.5-3 ppm and aromatic amines ...
Amines in hnmr and cnmr are examined.