The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Quinolinium thiocyanate》. Authors are Hurd, Charles D.; Wehrmeister, H. L..The article about the compound:quinoliniumhydrogensulphatecas:530-66-5,SMILESS:[O-]S(=O)(O)=O.C12=CC=C[NH+]=C1C=CC=C2).Quality Control of quinoliniumhydrogensulphate. Through the article, more information about this compound (cas:530-66-5) is conveyed.
The reaction of BzCl with quinoline (I) and CHNa(CO2Et)2 did not yield the desired 1,2-dihydroquinoline, since most of the I was recovered; the products (as determined by hydrolysis) are CHBz(CO2Et)2 and Bz(BzO)C:C(CO2Et)2. I (63 g.) and 156 g. KSCN in 600 ml. H2O, treated (7 min.) with 148 g. BzCl and stirred 1 hr., give 77% quinolinium thiocyanate, light yellow, m. 141-1.5°; FeCl3 gives a deep red color; heated 1 hr. on the steam bath with concentrated HCl it yields quinolinium H sulfate, m. 162-4°.
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Reference:
Thiazolidine – Wikipedia,
Thiazolidine – ScienceDirect.com