Tag: 200-300

Gong, Zhiming; Wang, Ru; Jiang, Yue; Kong, Xiangyu; Lin, Yue; Xu, Zhengjie; Zhou, Guofu; Liu, Jun-Ming; Kempa, Krzysztof; Gao, Jinwei published an article in 2021. The article was titled 《Novel D-A-D type small-molecular hole transport materials for stable inverted perovskite solar cells》, and you may find the article in Organic Electronics.HPLC of Formula: 624-28-2 The information in the text is summarized as follows:

Hole transport materials (HTMs), as a critical role in the hole extraction and transportation processes, highly influence the efficiency and stability of perovskite solar cells (PSCs). Despite that several efficient dopant-free HTMs have been reported, there is still no clear structure-property relationship that could give instructions for the rational mol. design of efficient HTMs. Thus, in this work, a series of donor-acceptor-donor (D-A-D) type carbazole-based small mols., TM-1 to TM-4, have been carefully designed and synthesized. By varing the electron acceptor unit from benzene to pyridine, pyrazine and diazine, their packing structure in single crystals, optical and electronic properties have shown a great difference. While as dopant-free HTM in p-i-n type PSCs, TM-2 improved the device photovoltaic performance with a power conversion efficiency from 15.02% (based on PEDOT:PSS) to 16.13%. Moreover, the unencapsulated device based on TM-2 retains about 80% of its initial efficiency after 500 h storage in ambient environment, showing the superior stability.2,5-Dibromopyridine(cas: 624-28-2HPLC of Formula: 624-28-2) was used in this study.

2,5-Dibromopyridine(cas: 624-28-2) belongs to pyridine. Pyridines form stable salts with strong acids. Pyridine itself is often used to neutralize acid formed in a reaction and as a basic solvent. HPLC of Formula: 624-28-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

《Enantiopure substituted pyridines as promising antimalarial drug candidates》 was published in Tetrahedron in 2020. These research results belong to Bentzinger, Guillaume; Pair, Etienne; Guillon, Jean; Marchivie, Mathieu; Mullie, Catherine; Agnamey, Patrice; Dassonville-Klimpt, Alexandra; Sonnet, Pascal. Formula: C5H3Br2N The article mentions the following:

The enantioselective synthesis and biol. evaluation of 4-(2-amino-1-hydroxyethyl)pyridines I [R1 = n-Bu, n-pentyl, n-hexyl, n-heptyl] as new antimalarial drug candidates was described. In particular, two routes to obtain the key-intermediate 4-vinyl-pyridine were studied. These routes were based on a Krohnke-type cyclization or on metal-catalyzed reactions. The Krohnke-type cyclization route was faster but only efficient at low scale since this pathway involved a Wittig reaction that requires severe temperature-control. Consequently, we designed a second route based on metal-catalyzed reactions. This way was longer but the 4-vinyl-pyridine could be obtained on a 5 g scale at least. Finally, a regioselective SN2 ring-opening of enantiopure epoxides by alkyl primary amines allowed the synthesis of eight I with global yields up to 41%. These compounds showed strong in vitro antimalarial activity against P. falciparum strains and were more active that chloroquine and mefloquine. These results demonstrated that I were promising antimalarial drug candidates. In the experimental materials used by the author, we found 2,6-Dibromopyridine(cas: 626-05-1Formula: C5H3Br2N)

2,6-Dibromopyridine(cas: 626-05-1) belongs to pyridine. Pyridine is widely used in the precursor to agrochemicals and pharmaceuticals. Also, it is used as an important reagent and organic solvent.Formula: C5H3Br2N

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Clarke, K.; Rothwell, K. published an article in 1960, the title of the article was A kinetic study of the effect of substituents on the rate of formation of alkylpyridinium halides in nitromethane solution.Product Details of 25813-24-5 And the article contains the following content:

Rates of reaction of substituted pyridines with CH2:CHCH2Br (I), MeI, PhCH2Br, and PrBr in MeNO2 were measured at several temperatures Substituents influenced both Arrhenius parameters, E and log PZ. In general, the logarithms of the rate constants varied linearly with the dissociation constants of the bases in H2O; however, the rates for the alkoxypyridines did not fit the linear relation, presumably due to a solvent effect, and those for the 2-substituted pyridines followed a different linear relation than those for the 3- and 4-substituted compounds Plots of log k against the Hammett substituent constants gave a somewhat scattered series of points, the 3- and 4-substituted compounds giving approx. linear relations with different slopes. The ortho effect influenced the activation energy, rather than the PZ factor. Primary steric hindrance was deemed important in the ortho effect. Changes in the free energy of ionization of pyridines and of activation for the Menschutkin reaction brought about by 2 substituents were algebraic sums of the changes brought about by the 2 groups individually, except in the case of 2,6- and 2,3-disubstituted compounds Rate constants (k × 104) at 60°, energies of activation (kcal./mole), and log PZ for reactions with I, and pK for ionization of the pyridine bases were (substituents shown): 2-Me, 7.53, 13.62, 5.83, 5.97; 3-Me, 71.4, 12.52, 6.06, 5.68; 4-Me, 81.7, 12.44, 6.07, 6.02; 2,3-Me2, 7.34, 13.86, 5.96, 6.60; 2,4-Me2, 14.6, 13.20, 5.82, 6.72; 2,5-Me2, 12.4, 13.31, 5.83, 6.47; 2,6-Me2, 0.18, -, -, 6.77; 3,4-Me2, 131.5, 12.20, 6.13, 6.52; 3,5-Me2 (II), 109.1, 12.37, 6.14, 6.14; 2-Et, 3.65, 13.94, 5.71, 5.99; 4-Et, 85.0, 12.46, 6.11, 6.02; 2,4,6-Me3, 0.31, -, -, 7.48; 2-OMe, -, -, – (no reaction), 3.40; 3-OMe, 41.3, 12.73, 5.96, 4.91; 4-OMe(III), 91.9, 12.38, 6.08, 6.55; 3-OEt, 45.7, -, -, -, 4-OEt, 104.0, 12.44, 6.18, 6.67; 3-Br, 5-OMe (IV), 5.56, 13.72, 5.75, -; 3-Br, 5-OEt (V), 6.38, 13.69, 5.78, -: 3-F, 5.69, 13.76, 5.77, 3.0; 3-Cl, 5.45, 13.72, 5.74, 2.84; 3-Br (VI), 5.87, 13.67, 5.13, 2.84; 3-CO2Et, 8.98, 13.58, 5.87, 3.35; 4-CO2Et, 10.0, 13.51, 5.87, 3.45; unsubstituted, 46.3, 12.73, 6.00, 5.17. The 2-F, 2-Cl, 3,5-Br2 (VII), 3,5-Br2 4-OMe, 3,5-Br2 4-Cl (VIII), 2-CO2Et, 4-OMe 5-NO2 (IX), and 4-OEt 5-NO2 (X) derivatives did not react with I at 60°. Kinetic measurements were made in 0.05M solution of the reactants, the extent of reaction being determined by Volhard titration of the bromide formed. VII (5 g.) in 75 ml. ether added to Me3CLi (from 1.3 g. Li) in ether at -35 to -40°, the mixture stirred 30 min., excess MeI in ether added, the ether removed, the residual paste acidified and steam-distilled, and the residue made alk. and steam-distilled gave II, b. 170.0-70.5°, m. -10°. The perbromide of pyridine hydrobromide treated by the method of Englert and McElvain (CA 23, 1901) gave, along with 3-bromo- and 3,5-dibromopyridine, a mixture of tribromopyridines from which 2,3,5-tribromopyridine, b. 160°, m. 45.0-5.5°, was isolated. VII (15 g.) refluxed 8 hrs. with MeOK (from 10 g. K) in 100 ml. MeOH, the solution filtered, acidified, and steam-distilled, the residue made alk. and steam distilled, the product extracted with ether, and HBr added gave 74% IV hydrobromide, m. 178.5-9.5°, from which IV, m. 33.5-4.0°, was liberated by addition of NaOH. V, b5 111°, m. 8.2-8.8°, was prepared similarly. VII and MeOK heated 5 min. at 140° and steam distilled gave 32% 3,5-dimethoxypyridine, isolated as the picrate; chloroplatinate m. 212-13° (decomposition) (alc. HCl). Chelidamic acid (20 g.) and 25 g. Br in H2O stirred 24 hrs., the product filtered off and decarboxylated 1 hr. at 200-240°, 15 g. PCl5 and 15 g. POCl3 added, the mixture heated 0.5 hr. at 125°, H2O added, and the mixture poured into iced aqueous KOH and steam-distilled gave 15.1 g. VIII, m. 98.0-8.5° (alc.). The latter (10 g.) added to MeOK (from 10 g. K) in 100 ml. MeOH and diluted with H2O gave 40% ether, m. 85-6° (alc.). Picolinic acid (20 g.) in 50 g. absolute EtOH and 50 g. H2SO4 refluxed 4 hrs., poured on ice, made alk. with NH3, and extracted with Et2O gave 20% Et picolinate, b47 153-4°. Et nicotinate, b21 116°, m. 9.6-10.0°, and Et isonicotinate, b21 111.5-12.0°, m. 7.0-7.5°, were similarly prepared in 80 and 40% yield, resp. Nitration of 4-hydroxypyridine (Koenigs and Freter, CA 19, 71) gave 15% 4-hydroxy-3,5-dinitropyridine, m. 315°, and no mononitro derivative The nitrate of III (2.5 g.), 10 g. fuming HNO3, and 10 g. fuming H2SO4 (containing 20% SO3) heated 24 hrs. on a steam bath gave 34% IX, m. 76.0-6.5°. X, m. 48.0-8.4°, was prepared similarly in 41% yield. The experimental process involved the reaction of 3,5-Dibromo-4-methoxypyridine(cas: 25813-24-5).Product Details of 25813-24-5

3,5-Dibromo-4-methoxypyridine(cas:25813-24-5) 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.Product Details of 25813-24-5

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

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

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Lee, T. B.; Swan, G. A. published an article in 1956, the title of the article was The constitution of yohimbine and related alkaloids. IX. Synthesis of 2-(4,5-diethyl-2-pyridyl)-3-ethylindole (alstyrine or coryline) and two related compounds.Recommanded Product: 98488-99-4 And the article contains the following content:

cf. C.A. 49, 12496a. Synthetic 2-(4,5-diethyl-2-pyridyl)-3-ethylindole and 4,5-diethylpyridine-2-carboxylic acid were identical with the appropriate degradation products of the Alstonia alkaloids and of corynantheine. Synthetic 3-ethyl-2-(5-ethyl-2-pyridyl)-5-methoxyindole did not appear to be identical with the degradation product from aricine. The 4-ethyl derivative of this was also synthesized. Adding 54 cc. 30% H2O2 to 86 g. 5-ethyl-2-methylpyridine in 250 cc. HOAc, after 5 hrs. at 70°, adding 40 cc. 30% H2O2 and keeping at 70-80° 15 hrs. gave a solution which on concentration in vacuo to 100 cc., addition of 100 cc. H2O and evaporation almost to dryness gave a residue which on basification (Na2CO3) and CHCl3 extraction afforded 52 g. 5-ethyl-2-methylpyridine N-oxide (I), b2 124-8°; picrate, m. 107-8°. Dropwise addition of a solution of 52 g. I in 98 cc. H2SO4 to a stirred mixture of 156 cc. H2SO4 and 175 cc. HNO3 (d. 1.2) at room temperature, followed by heating to 90-100° 3 hrs., cooling, and adding dropwise to stirred ice-NH4OH (d. 0.880) yielded 48 g. 5-ethyl-2-methyl-4-nitropyridine N-oxide, m. 80°. A solution of 10 g. of this in 50 cc. C6H6 on dropwise addition of 50 cc. PBr3 followed by refluxing 7 hrs. on a 125-40° bath gave a product which poured on ice, followed by basification (10% NaOH) and CHCl3 extraction gave 6.6 g. 4-bromo-5-ethyl-2-methylpyridine (II), b20 105-10°; picrate, m. 141-2° (decomposition); methiodide, m. 167-9°. Addition to a solution of 20 g. CuCN and 46 g. KCN in 180 cc. H2O of 28 g. II in 120 cc. EtOH followed by heating (autoclave, 180-200°, 4 hrs.), adjustment (concentrated HCl) to pH 4, removal of CuCN, evaporation to dryness, and drying by evaporation 3 times with EtOH gave a solid which on solution in 100 cc. EtOH, saturation with dry HCl, keeping overnight followed by 4 hrs. refluxing, removal of EtOH, basification and extraction afforded 12.15 g. Et 5-ethyl-2-methylpyridine-4-carboxylate (III), b2 112-15°; picrate, m. 129-30° (Berson and Cohen, C.A. 50, 9405i). Hydrolysis (20% KOH, reflux 90 min.) of III followed by adjustment to pH 4 gave by Et2O extraction the free acid, m. 226-8°, after purification by sublimation (140°/0.1 mm.). Addition of 12.5 g. III and 32 cc. EtOAc to KOEt (from 6.3 g. K) in C6H6 followed by 12 hrs. refluxing and addition of 140 cc. H2O gave a solution which after Et2O washing (to remove uncondensed ester), addition of 280 cc. concentrated HCl, heating overnight on a water-bath, evaporation to dryness, basification and Et2O extraction yielded 7.3 g. 4-acetyl-5-ethyl-2-methylpyridine (IV), b20 114-18°; picrate, m. 132-4°; oxime, m. 107°. Clemmensen reduction of 7.3 g. IV gave 4.3 g. 4,5-diethyl-2-methylpyridine (V), prepared by Kao and Robinson (C.A. 50, 5620b); styphnate, m. 155-6°. The residue from the working up contained 5-ethyl-4-(1-hydroxyethyl)-2-methylpyridine, b0.1 100-5° (picrate, m. 137-9°); reduction (HIP) of this base gave V. On refluxing 70 hrs. 4.3 g. V with 11 cc. BzH and 11 cc. Ac2O in 12 cc. xylene followed by acidification (17% HCl to Congo red), removal (steam distillation) of BzH, basification (NaOH), and CHCl3 extraction gave 1 g. unchanged V and 4.3 g. 4,5-diethyl-2-styrylpyridine (VI), picrate, m. 241-3° (decompose) (cf. K. and R., loc. cit.). Oxidation of 2 g. VI in Me2CO at 0° by the addition of 7 g. KMnO4 followed by 1 hr. stirring, removal and washing (Me2CO and H2O) of MnO2, and extraction of BzOH, gave on continuous Et2O extraction of the aqueous liquor at pH 4 0.6 g. 4,5-diethylpyridine-2-carboxylic acid (VII), m. 147-8°, λmaximum 2680 and 2300 A. (log ε 3.61 and 3.90 resp.), λmin. 2520 A. (log. ε 3.44), identical by mixed m.p. with acid of natural origin. Demethylation (Cu powder) of VII gave 4,5-diethylpyridine, identified as the picrate. VII (0.6 g.) on esterification (10 cc. EtOH and dry HCl at 0°, standing overnight and then refluxing for 2 hrs.) gave 0.6 g. Et ester (VIII), b3 140-5°; picrate, m. 88-90°. VIII (0.5 g.) with 5 cc. NH4OH (d. 0.880) 48 hrs. (room temperature) followed by 2 hrs. stirring yielded 2-carbamoyl-4,5-diethylpyridine (VIIIa), subliming at 100-20°/0.1 mm., m. 177-8°. Dehydration (1 cc. POCl3, reflux 2 hrs.) of 0.4 g. VIIIa gave on working up 0.2 g. 2-cyano-4,5-diethylpyridine, b20 150-60°, which (1.3 g.) in 75 cc. EtOH added with stirring to PrMgBr (from 0.6 g. Mg and 2.7 g. PrBr in 15 cc. Et2O), and the mixture refluxed 3 hrs. and decomposed (30 cc. saturated NH4Cl and 5 cc. concentrated HCl) afforded on basification and Et2O extraction 1.2 g. 2-butyryl-4,5-diethylpyridine (IX), b3 142-6°; picrate, m. 97-8°; phenylhydrazone picrate, m. 211-12°; p-methoxyphenylhydrazone picrate, m. 160-1°. On heating 0.334 g. IX with 0.18 g. PhNHNH2 in vacuo on a steam bath 2 hrs., the product, on solution in 20 cc. EtOH, cooling in ice, keeping at room temperature 1 hr. followed by refluxing 2 hrs., gave on evaporation, basification, and Et2O extraction 0.3 g. 2-(4,5-diethyl-2-pyridyl)-3-ethylindole (X), b0.4 200-10°, m. 110-1°, identical by mixed m.p. with alstyrine from alkaloidal degradation, λmaximum 3250 A. (log ε 4.36), and λmin. 2740 A. log ε 3.63; picrate, m. 218-21°; hydrochloride, softened at 190° and melted completely at 203°. As in the synthesis from VI above, starting from 4 g. ethyl 5-ethylpyridine-2-carboxylate there were obtained: 3 g. 2-carbamoyl-5-ethylpyridine, m. 147-8°; 1.7 g. 2-cyano-5-ethylpyridine, b20 132°; 1.3 g. 2-butyryl-5-ethylpyridine (XI) (p-methoxyphenylhydrazone picrate, m. 176-7°). XI with p-MeOC6H4NHNH2 yielded 3-ethyl-2-(5-ethyl-2-pyridyl)-5-methoxyindole (XII), m. 111-12°, λmaximum 3320 A. (log ε 4.49), λmin. 2720 A. (log ε 3.36); picrate, m. 201-3°. Similarly X with p-MeOC6H4NHNH2 gave 2-(4,5-diethyl-2-pyridyl)-3-ethyl-5-methoxyindole (XIII), b0.1 200-20°, m. 148°, λmaximum 3290 A. (log ε 4.43), λmin. 2730 A. (log ε 3.67); picrate, m. 225° (decomposition). Neither XII or XIII were identical with the degradation product from aricine (Goutarel, et al., C.A. 50, 5687g). The experimental process involved the reaction of 4-Bromo-5-ethyl-2-methylpyridine(cas: 98488-99-4).Recommanded Product: 98488-99-4

4-Bromo-5-ethyl-2-methylpyridine(cas:98488-99-4) 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.Recommanded Product: 98488-99-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Popp, Frank D.; McEwen, Wm. E. published an article in 1958, the title of the article was Approaches to the synthesis of emetine from Reissert compounds.Reference of 4-Bromo-5-ethyl-2-methylpyridine And the article contains the following content:

2-Methyl-4-nitro-5-ethylpyridine 1-oxide (94 g.) and 325 cc. PBr3 yielded by the method of Lee and Swan (C.A. 50, 13918g) 53% 2-methyl-4-bromo-5-ethylpyridine (I), b0.9 55-7°. EtBr added slowly with stirring to 36.48 g. Mg and 75 cc. dry Et2O, the mixture treated after the initial reaction had subsided with 108.5 g. I and 99.4 g. EtBr in 300 cc. dry Et2O at such a rate as to maintain gentle reflux, refluxed 2 hrs., the Et2O distilled, the residue diluted with 375 cc. dry C6H6, cooled, treated with 222.3 g. HC(OEt)3, refluxed 2 hrs., kept 15 hrs. at room temperature, treated with 500 cc. aqueous NH4Cl, the aqueous layer extracted with Et2O, the Et2O layer extracted with 1 l. N H2SO4 in portions, the acidic extract basified with aqueous NaHCO3, extracted with Et2O, and the extract worked up yielded 44.36 g. di-Et acetal (II) of 2-methyl-5-ethyl-4-pyridinecarboxaldehyde (III), b3 109-14°; picrate, m. 139-40° (EtOH) (all m.ps. are corrected). II (11.15 g.) in 90 cc. 10% HCl refluxed 2 hrs. under N, kept 16 hrs. at room temperature, basified with aqueous Na2CO3, extracted with CHCl3, and the extract worked up gave 6.57 g. III, b1 64-8°; oxime, m. 143-4° (EtOH). 3-Ethyl-4-methylpyridine was converted by the method of Berson and Cohen (C.A. 50, 9405i) to 69% 1-oxide (IV), b3 142-9°; picrate, m. 141.5-2.5° (EtOH). IV (186 g.) added slowly to 380 cc. warm Ac2O, refluxed 4 hrs., and evaporated gave 154 g. (3-ethyl-4-pyridyl)methanol acetate (V), b2.5 108-15°; picrate, m. 137-8° (EtOH). V (44.7 g.), 25 cc. 30% H2O2, and 115 g. glacial AcOH heated 4 hrs. on the steam bath, treated again with 21 cc. H2O2, heated 4 hrs., kept 36 hrs. at room temperature, evaporated in vacuo, the residue treated with 125 cc. Ac2O, heated 5.5 hrs. on the steam bath, concentrated in vacuo, treated with 175 cc. 6N HCl, refluxed 2 hrs., concentrated in vacuo, neutralized with aqueous NaOH, extracted with Et2O, and the extract worked up gave 10.2 g. 3-ethyl-4-pyridinecarboxaldehyde (VI), b2.5 71-5°; oxime, m. 146.5-8.5° (EtOH). VI (11.25 g.) and 52 cc. 13.5% alc. HBr kept 88 hrs. at room temperature, diluted with a large volume of C6H6, dried azeotropically during 24 hrs., evaporated, the residue basified with aqueous K2CO3, and the product isolated with Et2O gave 9.47 g. di-Et acetal (VIII) of VI, b1.9 100-2°; picrate, m. 115-16° (EtOH). 2-(p-Anisoyl)-6,7-dimethoxy-1,2-dihydroisoquinaldonitrile (VIII) (8.75 g.) in 45 cc. dry dioxane and 15 cc. dry Et2O treated at -20° under N slowly with stirring with PhLi (from 4.40 g. PhBr) in Et2O, then slowly with 3.38 g. VI, stirred 20 min. at -20° and 7 hrs. at room temperature, washed with H2O, 0.5N HCl, and H2O, distilled, and the gummy residue crystallized from EtOH gave 0.20 g. 6,7-dimethoxyisoquinaldonitrile (IX), m. 198.4-9.0° (EtOH); the HCl extract basified with aqueous NaOH, extracted with Et2O, the extract evaporated, and the gummy residue treated with EtOH gave 3.31 g. 1-(6,7-dimethoxyisoquinolyl)-4-(3-ethyl-4-pyridyl)carbinyl β-anisate (X), m. 248.2-8.7° (EtOH); the EtOH filtrate refluxed 2 hrs. with 2.8 g. KOH in 20 cc. H2O, the EtOH evaporated in vacuo, the aqueous residue extracted with Et2O, the precipitate filtered off, the extract evaporated, and the combined solids recrystallized from EtOH gave 1.57 g. 1-(6,7-dimethoxyisoquinolyl)-4-(3-ethyl-4-pyridyl)carbinol (XI), m. 168-9° (EtOH); the aqueous filtrate acidified gave 0.93 g. p-MeOC6H4CO2H. IX (0.02 g.) and 4.0 g. polyphosphoric acid heated 1 hr. on the steam bath, diluted with 10 cc. iced H2O, and neutralized with aqueous KOH gave 0.02 g. 6,7-dimethoxyisoquinaldamide, m. 169-70° (EtOH). 2-Benzoyl-6,7-dimethoxy-1,2-dihydroisoquinaldonitrile (1.45 g.) and 6 cc. SOCl2 heated 3 hrs. on the steam bath, evaporated in vacuo, the residue diluted with 35 cc. H2O, basified with aqueous NaOH, and the precipitate filtered off yielded 0.8 g. IX, m. 198.4-9.0° (EtOH). X (2.96 g.), 0.95 g. KOH, 25 cc. EtOH, and 55 cc. H2O refluxed 5 hrs., the EtOH evaporated in vacuo, and the aqueous residue filtered off gave 2.01 g. XI; the aqueous filtrate acidified gave 98% p-MeOC5H4CO2H. XI (0.5 g.), 0.5 g. Na2Cr2O7, and 10 cc. 80% AcOH stirred 1 hr. at room temperature, basified with aqueous NaHCO3, and extracted with CHCl3 gave 0.44 g. 1-(6,7-dimethoxyisoquinolyl) 3-ethyl-4-pyridyl ketone, m. 152-3° (ligroine). VIII (13.31 g.) in 70 cc. dry dioxane and 60 cc. dry Et2O treated under N at -25° slowly with stirring with PhLi from 6.60 g. PhBr in Et2O, then slowly with 5.70 g. III, stirred 1 hr. at -20°, kept 15 hrs. at room temperature, extracted with N HCl, washed, and the organic layer evaporated gave 4.06 g. IX; the HCl extract basified with aqueous NaOH, extracted with Et2O, the extract evaporated, the gummy residue (13.1 g.) dissolved in EtOH, the solution treated with 4.5 g. KOH in 30 cc. H2O, refluxed 1.5 hrs., the EtOH distilled, the aqueous distillation residue extracted with Et2O, and the extract worked up gave 3.95 g. 1-(6,7-dimethoxyisoquinolyl)(2-methyl-5-ethyl-4-pyridyl)carbinol, m. 174-5° (EtOH). 4-Pyridinecarboxaldehyde (XII) (50.0 g.) and 185 cc. 11.5% alc. HCl kept 90 hrs. at room temperature, diluted with 450 cc. dry C6H6, distilled with the azeotropic removal of the EtOH and H2O, the distillation residue basified with aqueous K2CO3, extracted with Et2O, and the extract worked up yielded 37.0 g. di-Et acetal (XIV) of XII, b6 99-100°. XIV (9.06 g.) and 9.25 g. Ph(CH2)2Br in 35 cc. dry xylene heated 1 hr. on the steam bath, the xylene solution decanted from a gummy precipitate, allowed to stand several days, diluted with a small amount of EtOH and a large amount of Et2O to precipitate more gum, and the combined precipitates crystallized from Et2O-EtOH gave 12.8 g. 1-phenethyl-4-(diethoxymethyl)pyridinium bromide (XV) dihydrate, m. 65.6-6.5°, which turned to a gum when dried over H2SO4 in vacuo; XV picrate, m. 104.6-5.6°. XV.2H2O (2.50 g.) in 25 cc. H2O treated with 8.8 g. K3Fe(CN)6 in 25 cc. H2O, kept overnight, diluted with 25 cc. C6H6, treated slowly with stirring at room temperature with 4.0 g. NaOH in 40 cc. H2O, stirred 1 hr., the aqueous layer extracted with C6H6, and the extract worked up gave 0.95 g. 1-phenethyl-4-(diethoxymethyl)-2(4H)-pyridone (XVI), m. 84.0-4.5°. 3,4-(MeO)2C6H3(CH2)2OH and PBr3 yielded 63% 3,4-(MeO)2C6H3(CH2)2Br (XVIII), b1.5 122-9°, m. 42-8°. XIV (3.62 g.) and 4.90 g. XVII heated 20 min. on the steam bath, kept overnight, and the gummy product treated with a small amount of EtOH and a large amount of Et2O yielded 4.90 g. 3,4-(MeO)2C6H3(CH2)2 analog (XVIII) of XV, m. 79-81.5°; picrate, m. 115.2-16.0° (EtOH). XVIII (2.83 g.) gave similarly 1.35 g. gummy product which, treated in EtOH, with a few drops of H2SO4, then with 2,4-(O2N)2C6H3NHNH2 solution, gave the 2,4-dinitrophenylhydrazone of 1-(3,4-dimethoxyphenethyl)-4-formyl-2(1H)-pyridone (XVIIIa), m. 270.0-70.8° (hot EtOH and hot Me2CO). VII (5.50 g.) and 6.44 g. XVII gave in the usual manner 90% 1-(3,4-dimethoxyphenethyl)-3-ethyl-4-(diethoxymethyl)pyridinium bromide (XIX), m. 140-1°; picrate, m. 126.3-7.1° (EtOH). XIX (4.54 g.) treated in the usual manner with K3Fe(CN)6 and the crude gummy product (2.90 g.) treated with EtOH, a few drops of H2SO4, and 2,4-(O2N)2C6H3NHNH2 solution yielded the 2,4-dinitrophenylhydrazone of the 3-Et derivative of XVIIIa, orange crystals, m. 268-9° (hot EtOH and hot Me2CO). 2-Methyl-5-ethyl-4-pyridinecarboxaldehyde di-Et acetal (3.41 g.) and 3.75 g. XVII yielded in the usual manner 43% 1-(3,4-dimethoxyphenethyl)-2-methyl-4-(diethoxymethyl)-5-ethylpyridinium bromide, m. 150.5-2.0° (Et2O-EtOH). The experimental process involved the reaction of 4-Bromo-5-ethyl-2-methylpyridine(cas: 98488-99-4).Reference of 4-Bromo-5-ethyl-2-methylpyridine

4-Bromo-5-ethyl-2-methylpyridine(cas:98488-99-4) 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.Reference of 4-Bromo-5-ethyl-2-methylpyridine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

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

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.Product Details of 861024-77-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

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

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Collins, Ian; Suschitzky, Hans published an article in 1970, the title of the article was Polyhaloaromatic compounds. XIV. Nucleophilic substitution and peroxy-acid oxidation of pentabromopyridine and some of its NN-dialkylamino- and bis(NN-dialkylamino)-derivatives.Category: pyridine-derivatives And the article contains the following content:

Pentabromopyridine was treated with various nucleophiles, such as alkoxides and primary and secondary amines. In the last case, with benzene as the solvent, 2(6)-substitution occurred exclusively, whereas use of EtOH as solvent produced the 4-isomer also. In all other cases a mixture of the 4- and 6-isomer was obtained. Oxidation of pentabromopyridine with peroxytrifluoroacetic acid yielded the corresponding 1-oxide as well as three isomeric tetrabromopyridine 1-oxides by protodebromination. Oxidation of 2-N,N-dialkylaminotetrabromopyridines gave hydroxylamines by mol. rearrangement of the intermediate N-oxide, whereas the 4-isomer gave a mixture of 4-nitroso-, 4-nitro-, and 4-aminotetrabromopyridines by an established mechanism. The nitro group in tetrabromo-6-nitropyridine was readily replaced with piperidine but not that in the 4-nitro isomer. Comparisons are drawn between the reactions of polybromo- and the corresponding polychloro-, and, in some cases, polyfluoropyridines, and reasons for differences are advanced. Concurrence of protodebromination and nucleophilic substitution is discussed. The experimental process involved the reaction of 3,5-Dibromo-4-methoxypyridine(cas: 25813-24-5).Category: pyridine-derivatives

3,5-Dibromo-4-methoxypyridine(cas:25813-24-5) 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.Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Talik, Zofia; Brekiesz-Lewandowska, Barbara published an article in 1970, the title of the article was 2-Fluoro-5-nitro-6-methylpyridine. II. Replacement of fluorine atom.Application In Synthesis of N,N-DIethyl-6-methyl-5-nitro-2-pyridinamine And the article contains the following content:

In the exchange reaction of the title compound with NH3, amines, hydrazine, water, and MeONa, I were prepared (X, m.p., and % yield given): NH2, 187°, 92.1; MeNH, 129°, 97.8; EtNH, 87°, 92.5; NHC2H4OH, 110°, 79.4; NHNH2, 122°, 74.7; PhNH, 133°, 97.2; NH(CH2)5Me, 50°, 98.5; C6H11NH, 113°, 98.5; PhNHNH, 142°, 96.5; Me2N, 132°, 86.2; Et2N, 38°, 95.4; morpholinyl, 137°, 98.2; OH, 230°, 94.1; MeO, 68°, 71.2. The experimental process involved the reaction of N,N-DIethyl-6-methyl-5-nitro-2-pyridinamine(cas: 28489-43-2).Application In Synthesis of N,N-DIethyl-6-methyl-5-nitro-2-pyridinamine

N,N-DIethyl-6-methyl-5-nitro-2-pyridinamine(cas:28489-43-2) 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.Application In Synthesis of N,N-DIethyl-6-methyl-5-nitro-2-pyridinamine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem