Category: 14121-36-9

Saraireh, Ibrahim A. M.; Altarawneh, Mohammednoor; Almatarneh, Mansour H. published the artcile< Thermochemical parameters of chlorinated compounds of pyridine>, Electric Literature of 14121-36-9, the main research area is chlorinated pyridine formation enthalpy charge heat capacity entropy.

Thermochem. and geometrical parameters of all chlorinated compounds of pyridine were calculated with the CBS-QB3 composite method. Standard entropies, standard Gibbs free energies of formation, standard enthalpies of formation, and heat capacities were computed and compared with their corresponding available exptl. data. Our calculated enthalpy values agree well with a rather limited corresponding exptl. data. Adjacent chlorinated sites in pyridine was found to incur a thermodn. penalty of 5.0 kcal/mol. While chlorination of pyridine is carried out at elevated temperatures in the gas and solvent media, acquiring the trend underpinning chlorination sequence at room temperature provides an insightful mechanistic insight. For this reason, we calculated Fukui indexes for electrophilic substitution and attempted to link obtained values with thermodn. stability orderings computed at 25 °C. Overall, the pattern and degree of chlorination induces very minor geometrical differences in reference to the unsubstituted pyridine. Calculated Fukui indexes predicts the chlorination sequence as follows; 2-chloro → 2,5-dichloro → 2,3,6-trichloro → 2,3,5,6-tetrachloro → 2,3,4,5,6-pentachloropyridine. However, a significant pos. charge accumulated in the N atom of the ortho-Wheland-type adduct renders its thermodynamically unstable by 8 kcal/mol in reference to the meta-Wheland intermediate. Overall, the sequence of chlorination is most likely to be sensitive to kinetics factors rather than thermodn. attributes; i.e., energies required to form the Wheland-type intermediates.

Computational & Theoretical Chemistry published new progress about Atomic charge. 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Electric Literature of 14121-36-9.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Suschitzky, H.; Chivers, G. E. published the artcile< Polyhaloaromatic compounds. XXI. Novel reagent system for the N-oxidation of weakly basic N-heteroaromatic compounds>, Safety of 2,3,4,6-Tetrachloropyridine, the main research area is pyridine oxidation pyridine oxide preparation; pyridazine oxidation pyridazine oxide preparation; pyrazine oxidation pyrazine oxide preparation; substitution nucleophilic pyridine.

By use of H2O2-H2SO4-AcOH or-CF3CO2H, pentachloro-, 2,3,4,6-tetrachloro-, 2,6-dichloro-, tetrachloro-4-nitro-, and pentabromopyridine, and tetrachloropyridazine and -pyrazine were oxidized to their N-oxides in >50% yields. 3,5-Dichloro-2,4,6-trifluoropyridine was oxidized by H2O2-polyphosphoric acid to give 3,5-dichloro-2,4-difluoro-6-hydroxypyridine 1-oxide; pentachloropyridine reacted with AcOH-H2SO4 to give 2,3,4,5-tetrachloro-6-hydroxypyridine by nucleophilic substitution.

Journal of the Chemical Society [Section] C: Organic published new progress about Oxidation. 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Safety of 2,3,4,6-Tetrachloropyridine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

den Hertog, H. J.; Schogt, J. C. M.; de Bruyn, J.; de Klerk, A. published the artcile< Derivatives of pyridine and quinoline. LXXXIII. Chloropyridines>, Recommanded Product: 2,3,4,6-Tetrachloropyridine, the main research area is .

2,4,5-Trichloropyridine has been synthesized, 6 other chloropyridines reëxamd., and the m. ps. and b. ps. of 19 chloropyridines determined Nicotinic acid (5 g.) divided in 2 tubes was shaken 4 h. at 250-70° with 42 g. PCl5 and 20 g. POCl3; steam distillation gave an oil and a precipitate which was refluxed 1 h. with 20 mL. 80% H2SO4, diluted with H2O, made basic, and steam-distilled; various fractions m. above 65° [cf. Seyfferth, J. prakt. Chem. 34, 241(1886)], and from the last fraction 2,3,5,6-tetrachloropyridine, m. 90-0.5°, was isolated. 3-Bromo-2,4-dihydroxypyridine (I) (5 g.) and 25 mL. 48% HBr heated 3 h. at 200° in 2 sealed tubes gave, after adding H2O and allowing to stand, 0.5 g. I and from the mother liquor 3.1 g. 5-bromo-2,4-dihydroxypyridine, m. 226.5-7.5°; 1 g. heated 2 h. at 200° with 10 mL. 38% HCl gave 3-chloro-2,4-dihydroxypyridine, decompose about 310°. Et 2,4-dihydroxy-5-pyridinecarboxylate (II) (3 g.) heated 2.5 h. at 115-20° with 18 g. POCl3 gave on steam distillation 90% of the 2,4-di-Cl compound (III), m. 31.5-2°. Saponification with an equivalent amount of dilute NaOH for 0.5 h. gave 80% 2,4-dichloro-5-pyridinecarboxylic acid “”hydrate”” (IV), m. 198° after liquefying at 155° and resolidifying, which could not be dehydrated by recrystallization from EtOH, C6H6, or ligroin, or by sublimation. IV (10 g.) and 10-15 g. POCl3 warmed to 100°, treated gradually with 30 g. PCl5, heated at 140° 0.5 h., evaporated under a vacuum, and the residue dissolved in C6H6 and saturated with NH3 gave 85% 2,4-dichloro-5-pyridinecarboxylic acid, m. 152-3° (from H2O). III (1.7 g.) in 2-3 mL. EtOH with 0.45 g. (NH2)2.H2O let stand 15 min. and a few ml. H2O added gave Et 2-chloro-4-hydrazino-5-pyridinecarboxylate, m. 147-8°; 1 g. suspended in 30 mL. boiling H2O treated dropwise with 35 mL. 10% CuSO4 solution, refluxed 2.5 h., and steam-distilled gave 45-50% Et 2-chloro-5-pyridinecarboxylate (V), saponified to the acid, m. 195° (decomposition) (amide, m. 211°). V (0.25 g.) heated 4 h. at 110° in a sealed tube with 0.1 g. Na in 6 mL. MeOH, diluted with H2O, acidified, and evaporated halfway gave 2-methoxy-5-pyridinecarboxylic acid, m. 171.5-2.5° (from H2O). 2,4-Dichloro-5-pyridinecarboxylic acid (4 g.) and 2 mL. POCl3 warmed to 100°, treated with 13 g. PCl5, warmed 0.5 h. at 140°, evaporated under a vacuum, taken up in C6H6, and saturated with NH3 gave 95% nitrile, m. 136-7°; 0.5 g. with 0.5 mL. Br in 50 mL. 7% KOH at room temperature for a few hrs., then a few hrs. at 70°, acidified, made basic, and extracted with Et2O gave 30-40% 2,4-dichloro-5-aminopyridine (VI), m. 80-1° (from ligroin). VI (0.5 g.) in 10 mL. 38% HCl in an ice-salt bath treated with 1.05 g. NaNO2 in 3 mL. H2O, then with 2.2 g. Cu powder, and steam-distilled gave 40-50% 2,4,5-trichloropyridine (VII), m. 8.5-9° (from aqueous EtOH). Heating 0.1 g. VII 4 h. at 160° with 2 mL. NH4OH (d. 0.9) gave 2,5-dichloro-4-aminopyridine, m. 119-20°; 0.02 g. in 0.5 mL. 38% HCl treated with 0.08 g. H2O2 and evaporated gave 2,3,5-trichloro-4-aminopyridine, m. 147°. NaNO2 with 1 g. 2-chloro-3-aminopyridine gave 0.5 g. 2,3-dichloropyridine, m. 66.5-7°, which with concentrated NH4OH at 190° 36 h. gave 2-amino-3-chloropyridine (VIII), m. 61.5-2°. Heating 0.7 g. 2,4-dihydroxypyridine (IX) with 4 mL. POCl3 2.5 h. at 130-40° gave on making basic, steam-distilling, and extracting with Et2O 60-5% 2,4-di-Cl compound, m. -1 to 0°, b760 189-90°; 0.6 g. with 16 mL. NH4OH heated at 170-80° 4.5 h., made basic, extracted with Et2O, evaporated, and the residue fractionally extracted with 20 mL. ligroin gave 0.05 g. 2-amino-4-chloropyridine, m. 129-30° (picrate, m. 236-43°); after an addnl. extraction with 35 mL. ligroin giving 0.1 g. crystals, 0.1 g. residue remained from which 4-amino-2-chloropyridine, m. 91-1.5°, could be isolated by crystallization 4-Nitraminopyridine (1.8 g.) with 11 mL. 38% HCl heated 10 h. at 100°, made alk., and steam-distilled gave in the 1st fraction (20 mL.) a little 4-chloro- (soluble in dilute HCl), and 10% 3,4,5-trichloropyridine, m. 71.5-2.5°. The 2nd fraction (100 mL.) gave (0.4 g. 4-amino-3,5-dichloropyridine (X), m. 159.5-60.5°. Koenigs, Mields, and Gurlt (C.A. 19, 70) suggested that X was 3,4-dichloropyridine (XII). However, the structure of X was indicated by its isolation in 55-60% yield from 4-aminopyridine by chlorination with HC1 and also from 4-amino-3-chloropyridine (XI). Reduction of 4-chloro-3-nitropyridine with Fe powder and AcOH gave 70% 3-amino-4-chloropyridine, m. 59.5-60.5° (N-Ac derivative, m. 113-13.5°; picrate, m. 181-1.5°); diazotization as before gave XII, m. 23-3.5°, b760 182-3°. XII heated 10 h. at 190° with NH4OH gave XI, m. 60.5-1.5° [picrate, m. 227-9° (decomposition)]; 0.2 g. XII with 0.04 g. Na in 2 mL. EtOH heated 4 h. at 160° gave a residue of 0.175 g. oily 3-chloro-4-ethoxypyridine (picrate, m. 159.5-60°; picrolonate, m. 202-3°). II with HCl and H2O2 gave 70% Et 2,4-dihydroxy-3-chloro-5-pyridinecarboxylate,m. 257-8°; POCl3 then gave 60% Et 2,3,4-trichloro-5-pyridinecarboxylate, m. 34°, 0.07 g. of which was boiled 1.5 h. with 4 mL. 1% NaOH and the Ag salt heated to 230° in a stream of CO2 with distillation, giving 2,3,4-trichloropyridine (XIII), m. 45-6°. IX with HCl and H2O2 gave 3-chloro-2,4-dihydroxypyridine (XIV), decompose about 310°; 0.2 g. I with 5 mL. 38% HCl at 200° 3 h. also gave XIV which was converted to XIII. Et 3-bromo-2,4-dihydroxy-5-pyridinecarboxylate with HCl, then POCl3, gave XIII. 2-Amino-3-chloro-4-bromopyridine (0.14 g.) in 50 mL. EtOH with 0.1 g. NaOH and 10 mg. Pd-Norit catalyst gave impure 2-amino-3-chloropyridine (impure picrate, m. 232-3°). XIII with NH4OH gave by filtration and extraction with ligroin 2-amino-3,4-dichloropyridine, m. 93-5° (picrate, m. 234.5-7°); the crystals less soluble in ligroin were 2,3-dichloro-4-aminopyridine (XV), m. 153.5-4.5° (picrate, m. 198.5-9.5°). XV with HCl and H2O2 gave 2,3,5-trichloro-4-aminopyridine, m. 150-2°. 2,6-Dichloro-4-aminopyridine (XVI) diazotized gave 85% 2,4,6-trichloropyridine (XVII), m. 32.5-3°, b760 217.5-18.5°. XVII with NH4OH gave 2-amino-4,6-dichloro-pyridine (most soluble in ligroin), m. 112.5°, and XVI, m. 170.3°. XVII with NaOMe as before gave 70-5% 2,4,6-trimethoxypyridine, m. 47-8°, which was converted to the 3,5-di-Cl derivative, m. 95.5-6°. 2,4-Dichloro-3-nitropyridine, prepared in 75% yield from IX, was reduced with Fe and AcOH, giving 85-90% 3-amino compound (XVIII), m. 69-9.5° (N-Ac derivative, m. 161-2°). XVIII (0.75 g.) in 15 mL. AcOH saturated with HCl was mixed with 0.7 mL. 30% aqueous H2O2 in 3.3 mL. AcOH, heated 0.5 h. at 80°, and poured into NaOH and Na2SO3 in H2O, giving 3-amino-2,4,6-trichloropyridine (XIX), m. 77.5-8°, and XVIII. Diazotization of XIX gave 75% 2,3,4,6-tetrachloropyridine (XX), m. 37.5-8°, b760 248-9.5°. XVI chlorinated as for XVIII gave 4-amino-2,3,6-trichloropyridine, m. 160-0.5°, which was converted to XX. The substance m. 74-5° [Sell and Dootson, J. Chem. Soc. 73,432(1898)] obtained by the chlorination of pyridine was therefore not XX.

Recueil des Travaux Chimiques des Pays-Bas et de la Belgique published new progress about 14121-36-9. 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Recommanded Product: 2,3,4,6-Tetrachloropyridine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Elvidge, J. A.; Zaidi, N. A. published the artcile< Heterocyclic syntheses with malonyl chloride. IX. 2-Substituted 4-chloro-6-pyrimidones from certain nitriles>, Application of C5HCl4N, the main research area is nitriles malonyl chloride; malonyl chloride nitriles; pyrimidines; pyridines.

Chloroacetonitrile with malonyl chloride yielded 2,3-dichloro-4,6-dihydroxypyridine (I) together with an unexpected product, 4-chloro-2-chloromethyl-6-pyrimidone (II). Further examples of this new synthesis of 2-substituted 4-chloro-6-pyrimidones were obtained with fluoro- and bromoacetonitrile, α-bromopropionitrile, and acetonitrile. Propio- and butyronitrile each gave a mixture of pyridine and pyrimidine product, while various other nitriles gave only the pyridine products. The expected fully substituted pyrimidone was obtained from fluoroacetonitrile and chloromalonyl chloride, and from dibromoacetonitrile with bromomalonyl chloride. Some novel halogen-transfer reactions were encountered in other cases.

Journal of the Chemical Society [Section] C: Organic published new progress about Nitriles Role: RCT (Reactant), RACT (Reactant or Reagent). 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Application of C5HCl4N.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Iddon, Brian; Meth-Cohn, Otto; Suschitzky, Hans; Taylor, Jack A.; Wakefield, Basil J. published the artcile< Carbon-13 NMR spectra of polychloropyridines; structural assignments>, Reference of 14121-36-9, the main research area is carbon NMR chloropyridine; pyridine chloro carbon NMR.

13C NMR spectroscopy is used to distinguish between the structures of 2- and 4-substituted tetrachloropyridines. Assignments are based on comparison with pyridine, nuclear Overhauser effects, off-resonance proton decoupling, empirical chem. shift increments, and 13C-19F coupling constants

Tetrahedron Letters published new progress about NMR (nuclear magnetic resonance). 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Reference of 14121-36-9.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Giacobbe, Thomas J.; McGregor, Stanley D.; Beman, Floyd L. published the artcile< Ultraviolet spectra of the chloropyridines and chlorinated pyridines possessing a sulfur (0SR), nitrogen (-NR2), or oxygen (-OR) substituent in either the 2 or 4 position. Convenient method for distinguishing such positional isomers>, Reference of 14121-36-9, the main research area is chloropyridine UV isomerism; pyridine chloro UV.

A correlation is established between the position (2 versus 4) of the S, N, or O substituent on the chlorinated pyridines and their uv spectra. The chlorinated pyridines with S, N, or O substitution at the 2-position give uv spectra whose longest wavelength absorption maxima are enhanced (moved to a greater wavelength and an increased extinction coefficient) when compared to the spectra of the 4-substituted isomers. The number of Cl atoms, and not their position, is the more significant factor in determining the overall character of the spectra.

Journal of Heterocyclic Chemistry published new progress about Isomers. 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Reference of 14121-36-9.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Ager, Ernest; Chivers, Geoffrey E.; Suschitzky, Hans published the artcile< Polyhalo aromatic compounds. XXVI. Photochemistry of pentachloropyridine and some derivatives>, Related Products of 14121-36-9, the main research area is photochem chloropyridine; pyridine chloro photochem; azabicyclohexenone tetrachloro.

Irradiation of pentachloropyridine in cyclohexane, Et2O, or dioxane gave 2,3,4,6-tetrachloropyridine (I) whereas in C6H6, tetrachloro-3-phenyl-pyridine was formed. Irradiation of pentachloropyridine 1-oxide and tetrachloro-N-methyl-2-pyridone gave CCl2:CClCCl:CClNCO and tetrachloro-2-methyl-2-azabicyclo[2.2.0]hex-5-en-3-one (II) resp. Nucleophilic substitution reactions of I were also examined

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) published new progress about Dechlorination. 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Related Products of 14121-36-9.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Iddon, Brian; Mack, Arthur G.; Suschitzky, Hans; Taylor, Jack A.; Wakefield, Basil J. published the artcile< Polyhaloaromatic compounds. Part 42. Carbon-13 NMR spectra of polyhalopyridines and 2-pyrimidines>, Synthetic Route of 14121-36-9, the main research area is carbon NMR polyhalo pyridine pyrimidine; substituent effect NMR halopyridine.

13C NMR spectra are reported for 103 polyhalopyridines and 8 polyhalopyrimidines. Substituent effects were calculated and the results used to assign structures.

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) published new progress about NMR (nuclear magnetic resonance). 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Synthetic Route of 14121-36-9.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Gomes, Jose R. B.; Amaral, Luisa M. P. F.; Ribeiro da Silva, Manuel A. V. published the artcile< Gas-phase thermochemistry of chloropyridines>, Electric Literature of 14121-36-9, the main research area is chloropyridine formation enthalpy metal cation affinity.

The gas-phase standard molar enthalpy of formation of 2,3,5-trichloropyridine was derived from the enthalpies of combustion of the crystalline solid measured by rotating-bomb calorimetry and its enthalpy of sublimation obtained by Calvet microcalorimetry at T = 298.15 K. The standard enthalpies of formation for this compound and for the other chloro-substituted pyridines were determined by DFT calculations The exptl. enthalpy of formation of 2,3,5-trichloropyridine is (65.8 ± 2.3) kJ mol-1, in excellent agreement with the B3LYP/6-311+G(2d,2p)//B3LYP/6-31G(d) value. The affinity of pyridine to some metal cations was also calculated at the same DFT level of theory and compared with exptl. data.

Chemical Physics Letters published new progress about Binding energy (of pyridine- and chloropyridine-cation complexes). 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Electric Literature of 14121-36-9.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Mack, Arthur G.; Suschitzky, Hans; Wakefield, Basil J. published the artcile< Polyhaloaromatic compounds. Part 39. Synthesis of the bromo- and iodo-tetrachloropyridines>, Recommanded Product: 2,3,4,6-Tetrachloropyridine, the main research area is bromotetrachloropyridine; iodotetrachloropyridine; pyridine bromo tetrachloro.

The title compounds I (R = Br, iodo, R1 = R2 = Cl; R = R2 = Cl, R1 = Br, iodo; R = R1 = Cl, R2 = Br, iodo) were prepared via the corresponding pyridylhydrazines or pyridyllithium or -magnesium derivatives Thus, reaction of pentachloropyridine N-oxide with N2H4 in EtOH (reflux 2 h) gave 2,3,4,5-tetrachloro-6-hydrazinopyridine which with Br-HBr gave 60% I (R = Br, R1 = R2 = Cl). Metalation of 2,3,4,6-tetrachloropyridine with BuLi followed by reaction with Br and iodine gave 58% I (R = R2 = Cl, R1 = Br) and 60% I (R = R2 = Cl, R1 = iodo), resp. Reaction of pentachloropyridine in THF with Mg at -10° gave 2,3,5,6-tetrachloro-4-pyridylmagnesium chloride which reacted with Br (-75°) to give 61% I (R = R1 = Cl, R2 = Br).

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) published new progress about 14121-36-9. 14121-36-9 belongs to class pyridine-derivatives, and the molecular formula is C5HCl4N, Recommanded Product: 2,3,4,6-Tetrachloropyridine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem