COA of Formula: C6H5NO3. So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic. Compound: 5-Hydroxynicotinic acid, is researched, Molecular C6H5NO3, CAS is 27828-71-3, about Application of the Hammett equation to substituted pyridines.
Rates of hydrolysis of Et 5-substituted nicotinates and pKa’s of 5-substituted nicotinic acids were measured and the Hammett relations discussed. Acetylation of 5-aminonicotinic acid (I) gave 5-acetamidonicotinic acid, m. 160-1°. Heating 30 g. 5-bromonicotinic acid, 25 g. KOH, 6 g. CuSO4·5H2O, 6 g. Na tartrate and 100 ml. H2O for 48 hrs. at 170-80° gave 65% 5-hydroxynicotinic acid, m. 292-3°. Methylation of Et 5-hydroxynicotinate with CH2N2 gave Et 5-methoxynicotinate, m. 42.5-3.5°, hydrolysis of which gave 5-methoxynicotinic acid, m. 136-7°. Oxidation of 10 g. I with 100 ml. 30% H2O2 and 200 ml. fuming H2SO4 (d. = 1.93) yielded 43% 5-nitronicotinic acid, m. 171-2°. The rates of hydrolysis of Et esters in 85 weight % EtOH with NaOH were obtained at 0°, 15° and 25° (5-substituent, Ea and log A given): Br, 16.5, 12.3; Cl, 17.5, 13.0; MeO, 15.8, 12.0; H, 17.0, 12.5; Me, 17.4, 12.9; NH2, 18.7, 13.7. The following Hammett equations were obtained: log k = 2.26 σm – 1.60 at 25°; log k = 2.13 σm – 1.99 at 15°; log k = 2.32 σm – 2.74 at 0°. The ratio of ρ at 25° for nicotinates and ρ at 25° for benzoates is 0.89. pKa’s obtained in 50 volume % EtOH at 25° for the following 5-substituted nicotinates were as follows: Me 4.92, H 4.70, MeO 4.57, Br 4.02, NO2 3.55. Thus log Ka = 1.73 σm – 4.75 hold. The ratio of ρ to that of substituted benzoic acids is 1.08. Thus the ratio of ρ’s of pyridine and benzene analogs is close to unity when cross-conjugation among substituents, reacting group, and N does not exist.
From this literature《Application of the Hammett equation to substituted pyridines》,we know some information about this compound(27828-71-3)COA of Formula: C6H5NO3, but this is not all information, there are many literatures related to this compound(27828-71-3).
Reference:
Chapter 1 An introduction to palladium catalysis,
Palladium/carbon catalyst regeneration and mechanical application method