Kolder, C. R.; den Hertog, H. J. published an article in 1953, the title of the article was Synthesis and reactivity of 5-chloro-2,4-dihydroxypyridine.HPLC of Formula: 861024-77-3 And the article contains the following content:
The synthesis of 5-chloro-2,4-dihydroxypyridine (I) is described. 4-Nitropyridine 1-oxide (II) (24 g.), prepared by known procedures was heated 6 hrs. at 110° (sealed tube) with 120 ml. SO2Cl2, giving 7 g. 2,4-dichloropyridine (III), b1.5 73-5°, and 5.5 g. recovered II. From heating the flask residue left from vacuum distillation of III with concentrated aqueous NH3 at 180° was obtained 1.5 g. 4-amino-2,3,5-trichloropyridine, m. 147-8°. III (12 g.) heated 5 hrs. at 170-80° (sealed tube) with 150 ml. aqueous NH3, 25 g. NaOH added, and the product extracted with Et2O gave 2 g. 2-amino-4-chloropyridine, m. 130-1°, and 6 g. 4-amino-2-chloropyridine (IV), m. 91-1.5°. IV (3 g.) heated 6 hrs. at 160° (sealed tube) with a solution of 1 g. Na in 15 ml. absolute EtOH gave 2 g. (60-5%) 4-amino-2-ethoxypyridine (V), m. 88-9°. V (0.4 g.) in 20 ml. saturated HCl treated dropwise with 0.25 g. NaNO2 in H2O in the cold gave 0.4 g. (85-90%) 4-chloro-2-ethoxypyridine (VI), m. -1 to + 1°; picrate, m. 130-1°. VI chlorinated in HOAc with Cl gas gave 75-80% 4,5-dichloro-2-ethoxypyridine (VII), m. 56-7°. VII (1 g.) heated 8 hrs. at 160° (sealed tube) with 1 g. NaOH in 20 ml. 50% aqueous EtOH gave 0.6 g. 5-chloro-2,4-diethoxypyridine (VIII), m. 56.5-57°, and 0.35-0.4 g. 5-chloro-2-ethoxy-4-hydroxypyridine, m. 201.5-2°. VIII (0.65 g.) heated 4 hrs. at 160° (sealed tube) with 20 ml. 25% aqueous HCl gave 0.47 g. (95-100%) I, m. 273-4° (decomposition) VII (0.1 g.) heated 4 hrs. at 160° (sealed tube) with 3 ml. 25% aqueous HCl gave 90-100% 4,5-dichloro-2-hydroxypyridine (IX), m. 231° (decomposition). IX heated with NaOEt solution as above gave 5-chloro-4-ethoxy-2-hydroxypyridine, m. 209.5-10.5°. IX heated 2.5 hrs. at 120-30° (sealed tube) with 3.5 ml. POCl3 gave 2,4,5-trichloropyridine (X), m. 8-9°. X heated with aqueous NH3 gave 4-amino-2,5-dichloropyridine, m. 125.5-26°; picrate, m. 164-5°. I heated with POCl3 gave X; POBr3 gave 2,4-dibromo-5-chloropyridine (XI), m. 61.5-2.5°. I heated with HCl or HBr at 250° gave only unchanged starting material but when heated in 48% aqueous HBr containing Br it gave 3-bromo-5-chloro-2,4-dihydroxypyridine (XII), m. 258-9° (decomposition), no depression with an authentic specimen. XII with POCl3 gave 3-bromo-2,4,5-trichloropyridine (XIII), m. 37-7.5°, and with POBr3 2,3,4-tribromo-5-chloropyridine (XIV), m. 77.5-8.5°. Mixed m.ps. of XI with the 3-Cl somer, of XIII with 5-bromo-2,3,4-trichloropyridine, and of XIV with 2,4,5-tribromo-3-chloropyridine all gave depressions indicating non-identity and serving as further evidence of the assigned structures. The experimental process involved the reaction of 2,4-Dibromo-3-chloropyridine(cas: 861024-77-3).HPLC of Formula: 861024-77-3
2,4-Dibromo-3-chloropyridine(cas:861024-77-3) belongs to pyridine-derivatives. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.HPLC of Formula: 861024-77-3