The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Chemical and biological properties of 2,3,5-trichloro-4-pyri- dinol》. Authors are Huraux, M. J.; Lawson, H. M..The article about the compound:2,3,5-Trichloropyridin-4-olcas:1970-40-7,SMILESS:OC1=C(Cl)C(Cl)=NC=C1Cl).Reference of 2,3,5-Trichloropyridin-4-ol. Through the article, more information about this compound (cas:1970-40-7) is conveyed.
2,3,5-Trichloro-4-pyridinol is a white solid with m.p. 216°. Its solubility in water is 0.057, in acetone 4, benzene 0.071, EtOH (95%) 4.21, xylene 0.3, and NaOH (1%) 5.35 g./100 g, at 23°. Its vapor pressure at 26° is 5.5 × 10-6mm. Hg, and its oral L.D.50 to rats is 80 mg./kg. The material is practically a non-irritant. It is readily taken up by both roots and foliage and translocated. The moderately long residual effect and activity against both annual and perennial grasses and seedlings of most broad-leaved species makes 2,3,5-trichloro-4-pyridinol (2.5-30 lb.) very suitable for total control of vegetation. Rates of <2 lb. applied in agricultural situations show little or no carry-over after 1 year. In logarithmic trials in Michigan, a rate of 6 lb. in mid-May (or in early July after mowing and removing the clip-pings) completely killed established Dactylis glomerata and Bromus inermis which were growing vigorously. Four lb. killed Agropyron repens. In Pennsylvania, rates of 10 lb. + picloram at 1 lb. applied as foliar sprays in early June provided excellent control of grasses and broadleaved weeds for up to 1 year. Even lower rates were effective against Cirsium arvense and other broad-leaved perennials, grasses on a railway embankment in England in May, and at an industrial site in July. In addition to these non-crop situations, 2,3,5-trichloro-4-pyridinol at 0.75-1 lb. pre-emergence and as post-emergence directed sprays at 0.5-2 lb. shows promise in sugar cane. When used in conjunction with a defoliant, it is also an outstanding inhibitor of cotton regrowth. After consulting a lot of data, we found that this compound(1970-40-7)Reference of 2,3,5-Trichloropyridin-4-ol can be used in many types of reactions. And in most cases, this compound has more advantages.
Reference:
Isoquinoline – Wikipedia,
Isoquinoline | C9H7N – PubChem