861024-77-3 | Pyridine-derivatives

den Hertog, H. J. et al. published their research in Recueil des Travaux Chimiques des Pays-Bas et de la Belgique in 1954 |CAS: 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

den Hertog, H. J.; Combe, W. P.; Kolder, C. R. published an article in 1954, the title of the article was The reactivity of halogen atoms occupying positions 3 and 5 in 2,4-dihydroxypyridine.HPLC of Formula: 861024-77-3 And the article contains the following content:

A survey is given of the rearrangements occurring during the heating of the monobromo and monochloro derivatives of 2,4-dihydroxypyridine substituted at positions 3 or 5 with Br and Cl. In this connection the reactivity of 3,5-dibromo-(I) and 3,5-dichloro-2,4-dihydroxypyridine (II) has been investigated. It has been found that the halogen atoms at position 3 are replaced by H in both compounds when they are heated with an aqueous solution of HBr to which NaHSO3 or PbNH2 is added. When, on the contrary, the dihalo derivatives are treated with H in the presence of a Pd catalyst, the halogen atom in the 5 position is replaced by H. 3-Chloro-2,4-dihydroxypyridine (0.2 g.) was heated 3 h. at 200° with 5 mL. of 48% aqueous HBr in a sealed tube and excess HBr evaporated The residue was 5-bromo-2,4-dihydroxypyridine (III), m. 228-30°. For identification it was heated with 3 g. of POBr3 for 3 h. at 160° in a sealed tube, the contents of the tube were poured onto ice, basified and distilled with steam to obtain from the distillate by filtration 2,4,5-tribromopyridine, m. 66-7°. 3,5-Dibromo-2,4-dihydroxypyridine (0.54 g.) and 0.19 g. of PhNH2 were heated in a sealed tube with 5 mL. of 48% aqueous HBr for 4 h. at 100°. The contents of the tube were made alk. with concentrated NaOH and extracted with ether. From the Et2O solution was obtained 0.33 g. 2,4-di-bromoaniline, m. 73-7°. The alk. solution was acidified with aqueous HBr to give 0.45 g. of a white precipitate essentially III. The mother liquors worked up brought the total yield of III to more than 85%. A mixture of 0.54 g. of II, 10 mL. of 48% aqueous HBr, and 1 g. of NaHSO3 was heated 3 h. at 200° in 2 sealed tubes. To the contents of the tubes aqueous NaOH solution was added until it showed a slightly acidic reaction, whereupon the liquid was continuously extracted with ether. From the ethereal solution 0.43 g. of 5-chloro-2,4-dihydroxypyridine, m. 265-70° (from alc.-ligroine), was obtained. Its identity was proved by converting it with POBr3 into 2,4-dibromo-5-chloropyridine, m. 59-60°. A solution prepared from 0.24 g. II and 0.2 g. of NaOH in 50 mL. of alc. was shaken with H over Pd-Norite catalyst. When 1.3 mmol of H had been taken up, the velocity of gas absorption diminished considerably. The catalyst was filtered off, and after the solvent had been distilled off, dilute aqueous HCl was added to the residue until faintly acid. 3-Chloro-2,4-dihydroxypyridine (0.105 g.), m. 310°, separated after some time. The mother liquors yielded an addnl. 0.05 g.; total yield, 0.155 g. 3,5-Dichloro-2,4-dihydroxypyridine (0.22 g.) was heated with 2 g. of POBr3 for 4 h. at 160° in a sealed tube to give 2,4-dibromo-3,5-dichloropyridine, m. 68.5-9° (from EtOH). The experimental process involved the reaction of 2,4-Dibromo-3-chloropyridine(cas: 861024-77-3).HPLC of Formula: 861024-77-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

den Hertog, H. J. et al. published their research in Recueil des Travaux Chimiques des Pays-Bas et de la Belgique in 1945 |CAS: 861024-77-3

den Hertog, H. J. published an article in 1945, the title of the article was Derivatives of pyridine and quinoline. LIX. Bromopyridines.Product Details of 861024-77-3 And the article contains the following content:

Pyridine (I) is brominated at 300° in the vapor phase and 3-bromopyridine (II) separated by distillation 3,5-Dibromopyridine (III) seps. upon cooling the residue; it is filtered off and the filtrate (400 g.) is fractionated under 20 mm. through a 20-cm. Widmer column. Fraction (1), 95° (55 g.), was II; (2), 95-100° (25 g.), was 3,4-dibromopyridine (IV) and III; (3), 100-5° (50 g.), was III, IV, and 2,5-dibromopyridine (V); (4), 105-10° (45 g.), was III, 2,3-dibromopyridine (VI), and V; (5), 110-15° (50 g.), was VI; (6), 115-20° (50 g.), was 2,6-dibromopyridine (VII); (7), 120-25° (30 g.), was VII; (8), 125-30° (20 g.), was VII and 3,4,5-tribromopyridine (VIII); (9), 130-35° (15 g.), was VII, VIII, and 2,3,5-tribromopyridine (IX); (10), 135-140° (20 g.), was VIII and IX; (11), 140-45° (25 g.), was VIII and IX; residue (15 g.). Fraction (3) (typical treatment) was shaken with 80 ml. of 8% HCl, the insoluble portion (A) separated from the soluble portion (B) which was poured into concentrated NH4OH. The crystals which separated (10 g.), recrystallized from petr. ether, yielded 5.5 g. of IV, m. 70-1°. (A) was extracted twice with dilute HCl. The soluble part, isolated and recrystallized from EtOH (3.5 g.), was identified as III, m. 110-11°. The insoluble residue, extracted with 25% HCl (110 ml.), gave 5 g. of an insoluble residue, recrystallized from EtOH and identified as V, m. 93-4°. Fraction (5) was shaken with 100 ml. 12% HCl, and the soluble part (C) removed from the insoluble part (D). (C) contained III. (D), recrystallized from EtOH, was identified as V. The mother liquor yielded an oil which, recrystallized from benzene, then from acetone-water, yielded VI, m. 58-9°. Fraction (10), recrystallized from EtOH, yielded 3 g. VIII, m. 106.5-7.5°. The mother liquor yielded an oil which was extracted with HCl. The residue, recrystallized from EtOH, gave needles of IX, m. 44-5°. IV was obtained from fraction (2) by again distilling under 20 mm., collecting the 99-106° fraction (55 g.), extracting with 85 ml. 8% HCl, and pouring the solution into NH4OH; the resulting 13 g. oil, recrystallized from benzene, yielded 8 g. (0.4%) of IV, m. 71-2°, decomposes on distillation IV (1 g.) was heated 8 hrs. at 160° with 10 ml. NH4OH (sp. gr. 0.9) in sealed tubes, made basic, and extracted with ether. Removal of the ether left an oil which recrystallized from benzene and ligroin with difficulty. The product, 4-amino-3-bromopyridine (X), forms a picrate, m. 235-6°, which yields X, m. 69.5-70.5°, when treated with base, distilled with steam, extracted with ether, dried, and poured into petr. ether. X (0.17 g.) in 1 ml. 20% H2SO4 was reacted with 0.20 ml. Br in 1.5 ml. HOAc, made basic, extracted with ether, the ether removed, and the residue recrystallized from aqueous EtOH, yielding 4-amino-3,5-dibromopyridine (XI). IV upon standing 8 months decomposes to form a N-pyridylpyridinium compound (XII), m. 205-9°. XII heated with NH4OH (sp. gr. 0.9) 8 hrs. in a sealed tube (200°) yielded X. IV (1 g.) heated 15 min. at 140° yielded yellow crystals which, when extracted by refluxing with EtOH, yielded 1-(3-bromo-4-pyridyl)-3-bromo-4-pyridone, m. 243-4°. 2,3,6-Tribromopyridine (1.8 g.) was reduced (2 hrs., H, Pd on Norit, 5%) in 50 ml. MeOH and 2 ml. 12% NaOH, the solution made basic and extracted with ether, the ether removed, the residue treated with 10% HCl, the solution made basic with NH4OH, and the precipitate recrystallized from aqueous EtOH, yielding VI, m. 57-8°. VI (0.35 g.) was heated at 170° in a sealed tube with 8 ml. NH4OH (sp. gr. 0.9), then made basic with NaOH and extracted with ether, the ether removed, and the residue recrystallized from ligroin, yielding 2-amino-3-bromopyridine (XIV), m. 64.5-5.5°, 0.27 g. of which, dissolved in 20% H2SO4 and mixed with 0.4 g. Br in 4.5 ml. HOAc and heated 20 min., then treated with Na2CO3 solution, yielded 0.4 g. 2-amino-3,5-dibromopyridine, m. 103-4° (from ligroin). Heating 2,4-dibromopyridine with NH4OH yielded 2-amino-4-bromopyridine (XV), m. 143-4.5° (picrate, m. 262-3°) and 4-amino-2-bromopyridine (XVI), m. 97.5-8.5° (picrate, m. 129-30°). Bromination of XVI yielded 4-amino-2,3,5-tribromopyridine, m. 147-8°, and 4-amino-2,3-dibromopyridine, m. 171-3°. 2,4-Dihydroxypyridine in 48% HBr and Br yielded 3-bromo-2,4-dihydroxypyridine (XVII), m. 263.5-4.5° (decomposition). XVII with POBr3 in a sealed tube yielded 2,3,4-tribromopyridine (XVIII), m. 84-5°. The structure was proved by synthesis of XVIII from 3-bromo-2,4-dihydroxy-5-pyridinecarboxylic acid (XIX). XIX heated with 38% HCl was converted to 3-chloro-2,4-dihydroxypyridine (decomposes 310°) which, heated with POBr3, yielded 3-chloro-2,4-dibromopyridine (XX), m. 70-70.5°. XX heated with NH4OH yielded 2-aminobromochloropyridines of unknown structure. XVIII heated with NH4OH yielded 2-amino-3,4-dibromopyridine (XXI), recrystallized from aqueous EtOH, m. 128-9°, and 4-amino-2,3-dibromopyridine (XXII), recrystallized from ligroin-EtOH, m. 173-5°. XXII reduced in basic solution (H, Pd) yielded 4-amino-pyridine, m. 158°. XVIII was also prepared from 2,4-dimethoxypyridine by heating with PBr5 and POBr3. Bromination of 2,4-dihydroxypyridine yielded 3,5-dibromo-2,4-dihydroxypyridine, which, treated with 48% HBr, yielded 2,4,5-tribromopyridine (XXIII), recrystallized from aqueous EtOH, m. 66.5-7.5°. XXIII heated with NH4OH yielded 4-amino-2,5-dibromopyridine, recrystallized from aqueous EtOH, m. 147-8°. VIII when brominated at 500° yielded 2,3,4,5-tetrabromopyridine (XXIV), recrystallized from aqueous EtOH, m. 74.5-5.5°. XXIV was also prepared by heating 2,4-dihydroxypyridine with PBr5 and POBr3 for 5.5 hrs. at 120-5°. XXIV heated with NH4OH as before yielded 4-amino-2,3,5-tribromopyridine, m. 148-8.5°. A table of constants of known bromopyridines is given. The experimental process involved the reaction of 2,4-Dibromo-3-chloropyridine(cas: 861024-77-3).Product Details of 861024-77-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Kolder, C. R. et al. published their research in Recueil des Travaux Chimiques des Pays-Bas et de la Belgique in 1953 |CAS: 861024-77-3

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem