Bojarska-Dahlig, H. N. published the artcileDerivatives of pyridine N-oxide. XV. Synthesis and reactivity of N-[4-oxo-1(H)-pyridyl]oxyacetic acid, Category: iodides-buliding-blocks, the publication is Recueil des Travaux Chimiques des Pays-Bas et de la Belgique (1958), 331-9, database is CAplus.
cf. C.A. 51, 15516a. 4-Hydroxypyridine N-oxide (I) in alk. medium with ClCH2CO2H yielded almost 60% title compound (II), decomposed with CH2N2 to give 4-MeOC6H4N, CO2, and HCHO. I (3.33 g.) in 20 ml. H2O containing 3.12 g. NaOH kept 5 hrs. at 90-5° with 4.23 g. ClCH2CO2H, the mixture adjusted to pH 3 with acid, kept overnight at 0°, and crystallized (H2O) yielded 57% II, C7H7NO4, m. 164-5°. II (0.4 g.) in 90% alc. hydrogenated with Pd-C (4 mg. PdCl2 reduced in 25 ml. 96% alc. in the presence of 36 mg. C) and the filtered solution evaporated gave 4-oxo-1 (H)-pyridone (III); nitrate, m. 194-5° (decomposition). II (0.845 g.) heated 5 hrs. with 2 g. Ba(OH)2 in 10 ml. H2O, the mixture treated with dilute H2SO4, the filtered solution (A) concentrated, and the residue treated with fuming HNO3 at 0° yielded 63% III nitrate. A acidified with AcOH and treated with concentrated aqueous CaCl2 gave (OHCCO2)2Ca. II (0.1 g.) boiled 2 min. with 3 ml. 2N NaOH and the solution (1 ml.) acidified with dilute H2SO4 and treated with 1 drop 0.1% aqueous indole and 1 ml. H2SO4 gave a red color. The solution (1 ml.) acidified with AcOH and treated with a few drops of egg white and 1 ml. H2SO4 gave a pos. Adamkiewicz reaction for OHCCO2H (IV). (CO2H)2, produced by partial conversion of IV, was detected in the rest of the liquid. II (0.845 g.) and 0.84 g. CH2N2 in 240 ml. Et2O kept 20 hrs. at room temperature, the Et2O evaporated, the residue treated with 10 ml. alc. picric acid, and the product recrystallized (alc.) yielded 52% 4-MeOC5H4N.C6H3N3O7, m. 173-4°. The presence of CO2 and HCHO was demonstrated but no trace of IV was found. I. (1.65 g.) in 50 ml. H2O containing 2.4 g. Na2CO3 at 95-100° treated dropwise with vigorous stirring with 7.8 g. iodine in 24 ml. H2O containing 7.8 g. KI, the mixture kept 1 hr. at 95-100°, the free iodine removed with KHSO3, the solution adjusted to pH 2 with concentrated HCl, the mixture kept 10 hrs., filtered, the crude product (3.52 g.) boiled with 4% aqueous HCl, and the residue washed with H2O gave 3,5-diiodo-4-hydroxypyridine N-oxide (V), m. 340-3° (decomposition), also obtained in 13% yield by stirring 1.65 g. I and 3.2 g. NaOH in 50 ml. H2O at 95-100° with addition of 7.62 g. iodine in 40 min., heating the mixture 1 hr. at 95-100°, repeatedly precipitating with concentrated HCl, and dissolving the precipitate in concentrated NaOH, or by treating 1 g. I in 5 ml. 20% HCl 2 hrs. at 95-100° with HgICl in 8 ml. 20% HCl, diluting the mixture with 80 ml. H2O, heating 2 hrs. at 95-100°, treating with NaHSO3, and filtering. V (3.63 g.) in 25 ml. H2O containing 1.44 g. NaOH heated 5 hrs. at 90-5° at pH 8 with 1.88 g. ClCH2CO2H, the mixture adjusted to pH 2 with concentrated HCl, kept 12 hrs. at room temperature, filtered, the precipitate (3.85 g.) boiled with 100 ml. H2O, filtered from 0.94 g. V, the filtrate evaporated, and the residue (2.88 g.) recrystallized (H2O) gave authentic N-(3,5-diiodo-4-oxo-1(H)-pyridyl)acetic acid (VI), m. 250.5-1.5°, methylated with CH2N2 in Et2O to VI Me ester (VII), m. 198-8.5° (50% MeOH), not yielding a picrate with picric acid in alc. V (1 g.) heated 5.5 hrs. on a steam bath in 15 ml. 10% NaOH and the cooled solution acidified below pH 2 with concentrated HCl gave 87% unchanged V. The ultraviolet absorptions of 10-4M solutions in 50% alc. were determined and tabulated [compound, and λmaximum and λmin. in mμ (log ε) given]: II, 268, 222 (4.1, 2.85); 4-benzyloxypyridine N-oxide (cf. Shaw, C.A. 43, 2997e), 269, 231 (4.3, 3.05); N-benzyloxy-4-oxo-1(H)pyridine, 268, 230 (4.3, 2.8); VI, 238 and 285, 257 (4.1 and 3.95, 3.65); VII, 238 and 285, 257 (4.0 and 3.95, 3.65); N-(4-oxo-1 (H)-pyridyl)acetic acid, 202 and 261, 221 (4.1 and 4.2, 3.1); Et N-(4-oxo-1 (H)-pyridyl)acetate, 204 and 260, 221 (4.1 and 4.25, 2.8).
Recueil des Travaux Chimiques des Pays-Bas et de la Belgique published new progress about 101-29-1. 101-29-1 belongs to iodides-buliding-blocks, auxiliary class Pyridine,Iodide,Carboxylic acid,Ketone, name is 2-(3,5-Diiodo-4-oxopyridin-1(4H)-yl)acetic acid, and the molecular formula is C7H5I2NO3, Category: iodides-buliding-blocks.
Referemce:
https://en.wikipedia.org/wiki/Iodide,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com