The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Preparation of 3-(2-hydroxyethyl)pyridine》. Authors are Dornow, Alfred; Schacht, Wilhelm.The article about the compound:3-Pyridinepropionic acidcas:3724-19-4,SMILESS:OC(=O)CCC1=CC=CN=C1).Computed Properties of C8H9NO2. Through the article, more information about this compound (cas:3724-19-4) is conveyed.
Attempts to prepare 3-(2-hydroxyethyl)-2-methylpyridine analogous to the 5-(2-hydroxyethyl)-4-methylthiazole component of vitamin BI (I) from the corresponding 3-AcOCH2CO compound by Clemmensen reduction had given the (1-hydroxyethyl) compound, which, as well as 3-(1-hydroxyethyl)pyridine itself, yielded with the pyrimidine component of I compounds (II) having I activity in the pigeon test (C.A. 34, 5845.5). Since the (1-hydroxyethyl) isomer of I showed no aneuritic action (C.A. 37, 3091.5) it was to be expected that the (2-hydroxyethyl) isomers of compounds of this type would have increased vitamin activity. 1-(4-Amino-2-methyl-5-pyrimidylmethyl)-3-(2-hydroxyethyl)pyridinium chloride-HCl (III) was accordingly prepared by the following series of reactions. Quinolinic acid nitrate, C7H5NO4.HNO3, m. 152-4° (from dilute HNO3), prepared quantitatively from 8-hydroxyquinoline and HNO3 (d. 1.4) at 0-5°, was converted by heating 3 hrs. at 200-10° into nicotinic acid, m. 224-6° (85-90%), thence through the Me ester and hydrazide into the phenylsulfonylhydrazide which, decomposed with Na2CO3 in glycerol at 160°, gave, along with Ph2S2, 36% 3-pyridinecarboxaldehyde, b18 88-90°; this, heated 2 hrs. on the water bath with 1 mol. CH2(CO2H)2 in pyridine and a couple drops of piperidine, yielded 90-5% 3-pyridineacrylic acid, quantitatively hydrogenated by Pt oxide in water in 6-8 hrs. to 3-pyridinepropionic acid, m. 160-2° (from alc. or much AcOEt); Me ester (75-80% by refluxing the acid 3 hrs. in MeOH-concentrated H2SO4), b12 134.2-4.4°; amide (quant. yield from the ester allowed to stand several hrs. with 5 volumes concentrated NH4OH), prisms from acetone, m. 118-19°, converted by Br and KOH on the water bath into 3-(2-aminoethyl)pyridine, b14 115.0-15.4°, very hygroscopic and sensitive to CO2 (dipicrate, leaflets or needles from water, m. 211-12°; HCl salt, m. 204-5° (from alc. or alc.-acetone)); treated in ice-cold N H2SO4 with NaNO2 and heated on the water bath, the amine gave 75-80% 3-(2-hydroxyethyl)pyridine, b10 144.0-4.5° (urethan, scales from water, m. 100-2°), which, heated with 4-amino-5-(chloromethyl)-2-methylpyrimidine-HCl in PhNO2 1 hr. at 40°, gave 45-8% III, druses with 1 H2O from MeOH-Me2CO, m. 212-14°. Physiol. tests on III will be reported later.
In addition to the literature in the link below, there is a lot of literature about this compound(3-Pyridinepropionic acid)Computed Properties of C8H9NO2, illustrating the importance and wide applicability of this compound(3724-19-4).
Reference:
Imidazole – Wikipedia,
Imidazole | C3H4N2 – PubChem