Reaction of bis(2,4-dinitrophenyl) phosphate with hydrazine and hydrogen peroxide. Comparison of O- and N- phosphorylation

Nonionic hydrazine reacts with anionic bis(2,4-dinitrophenyl) phosphate (BDNPP), giving 2,4-dinitrophenyl hydrazine and dianionic 2,4-dinitrophenyl phosphate by an S(N)2(Ar) reaction, and at the phosphoryl center, giving 2,4-dinitrophenoxide ion and a transient phosphorylated hydrazine that rearranges intramolecularly to N-(2,4-dinitrophenyl)-N-phosphonohydrazine. Approximately 58% of the reaction at pD = 10 occurs by N-phosphorylation, as shown by (31)P NMR spectroscopy. Reaction of HO(2)(-) is wholly at phosphorus, and the intermediate peroxophosphate reacts intramolecularly, displacing a second 2,4-dinitrophenoxide ion, or with H(2)O(2), giving 2,4-dinitrophenyl phosphate and O(2). Rate constants of O- and N-phosphorylation in reactions at phosphorus of NH(2)NH(2), HO(2)(-), and NH(2)OH and its methyl derivatives follow Bronsted relationships with similar slopes, but plots differ for oxygen and nitrogen nucleophiles. The reaction with NH(2)NH(2) has been probed by using both NMR spectroscopy and electrospray ionization mass and tandem mass spectrometry, with the novel interception of key reaction intermediates in the course of reaction.     

Unusual dealkylations and rearrangements in aromatic nucleophilic substitution

The reaction of 2,4-dinitrohalobenzenes with di-isopropylamine produces mainly N-(2,4-dinitrophenyl)-isopropylamine and N-(2,4-dinitrophenyl)-n-propylamine instead of the expected straightforward substitution product. Dealkylations are also observed in the reactions with isopropylcyclohexylamine and dicyclohexylamine. A carbanionic mechanism is proposed.     

Change of mechanism with a change of substituents for a Zincke reaction

The reaction between N-(2,4-dinitrophenyl)-4-(4-pyridyl)pyridinium chloride and 4-aminothiophenol led to an unexpected displacement of the 2,4-dinitrophenyl group, in contrast with the normal Zincke product formed with other nucleophilic 4-substituted anilines. Evidence for a SET process was obtained from EPR spectra of the reaction mixture.     

Deprotonated N-(2,4-Dinitrophenyl)amino Acids Undergo Cyclization in Solution and the Gas Phase

The collisionally activated mass spectral fragmentations of N-(2,4-dinitrophenyl)alanine and phenylalanine [M - H](-) may be gas-phase analogs of the base-catalyzed cyclization of N-(2,4-dinitrophenyl)amino acids in aqueous dioxane. This latter reaction is one source of the 2-substituted 5-nitro-1H-benzimidazole-3-oxides, which are antibacterial agents. The fragmentation of both compounds, established by tandem mass spectrometric experiments and supported by molecular modeling using DFT methods, indicate that the [M - H](-) ions dissociate via sequential eliminations of CO(2) and H(2)O to produce deprotonated benzimidazole-N-oxide derivatives. The gas-phase cyclization reactions are analogous to the base-catalyzed cyclization in solution, except that in the latter case, the reactant must be a dianion for the reaction to occur on a reasonable time scale. The cyclization of N-(2-nitrophenyl)phenylalanine, which has one less nitro group, requires a stronger base for the cyclization than the compound with a second nitro group at the 4-position. Following losses of CO(2) and H(2)O are expulsions of both neutral molecules and free radicals, the latter being examples of violations of the even-electron ion rule.     

The solid-phase Zincke reaction: preparation of omega-hydroxy pyridinium salts in the search for CFTR activation

A study of structural modifications of MPB-07 was undertaken as part of a synthetic program aimed at discovering small molecules with CFTR activation potential. Solid-phase synthesis techniques were used to prepare derivatives of MPB-07 employing the Zincke reaction for the construction of aromatic, quaternary ammonium salts such as those found in 2 or 3. In this transformation, primary amines react with highly electrophilic N-2,4-dinitrophenylpyridinium (DNP) salt 4 to afford pyridinium salt 8 with release of 2,4-dinitroaniline 6. Thus, the reaction of 1-(2,4-dinitrophenyl)pyridinium salts with various polymer-bound amino ethers, followed by cleavage from the resin, delivers the desired salts in good yield and high purity.     

On the synthesis and reactivity of the Z-2,4-dinitrophenylhydrazone of 5-amino-3-benzoyl-1,2,4-oxadiazole

The synthesis of the title compound (4b) has been completed: its rearrangement (in dioxane/water; 1:1, v/v) into N-(2,4-dinitrophenyl)-5-phenyl-2H-1,2,3-triazol-4-ylurea (7) has been quantitatively studied in a wide reactivity (at 293 K, k(A) 10(-8) -4 s(-1)) and pS+ (4.5-14.1) range and compared with that of the Z-2,4-dinitrophenylhydrazone of 3-benzoyl-5-phenyl-1,2,4-oxadiazole (10), of the 3-(p-nitro)phenylureine of 5-phenyl-1,2,4-oxadiazole (13), and of N-(5-phenyl-1,2,4-oxadiazol-3-yl)-N'-p-nitrophenylformamidine (14). The results (reactivity, occurrence of specific or general base-catalysis, evidence for or absence of rate-limiting constants) have been well interpreted considering the structure of the side-chains involved and the stability of the final rings obtained in the rearrangements.     

Reaction of 3,4,6-trioxoalkanoic acid esters with 2,4-dinitrophenylhydrazine

Methyl 3,4,6-trioxoalkanoates (3,4-dihydroxy-6-oxo-2,4-alkadienoates) reacted with 2,4-dinitrophenylhydrazine to give methyl 3,6-bis[(2,4-dinitrophenyl)hydrazinylidene]-4-oxoalkanoates or methyl {5-alkyl-2-hydroxy-1-(2,4-dinitroanilino)-3-oxo-2,3-dihydro-1H-pyrrol-2-yl }acetates. Alkyl 3,6-bis[(2,4-dinitrophenyl) hydrazinylidene]-4-oxoalkanoates were also synthesized by reaction of disodium 1-alkoxy-1,6-dioxoalka-2,4-diene-3,4-diolates with 2,4-dinitrophenylhydrazine.     

Nitropyrazoles 15. Synthesis and some transformations of 1-(2,4-dinitrophenyl)-4-methyl-3,5-dinitropyrazole

The method for preparation of 1-(2,4-dinitrophenyl)-4-methyl-3,5-dinitropyrazole has been developed. Due to the larger CH-acidity of 4-Me-group compared to 1,4-dimethyl-3,5-dinitropyrazole, 1-(2,4-dinitrophenyl)-4-methyl-3,5-dinitropyrazole is capable of reacting with substituted benzaldehydes to afford 4-[(E)-2-arylvinyl]-1-(2,4-dinitrophenyl)-3,5-dinitropyrazoles. Under the action of nucleophiles, dinitrophenyl group is detached from the former compounds leading to previously unknown N-unsubstituted 4-[(E)-2-arylvinyl]-3,5-dinitropyrazoles.     

A convenient method for N-1 arylation of uracil derivatives

1-(4-Nitrophenyl)- and 1-(2,4-dinitrophenyl)uracil derivatives have been obtained by direct arylation of uracil and its 5-substituted derivatives using 1-fluoro-4-nitrobenzene or 1-fluoro-2,4-dinitrobenzene in the presence of a base. The application of the newly obtained uracil derivatives in further synthesis is also presented.     

Reaction of 3,4-dioxohexane-1,6-dioic acid esters with 2,4-dinitrophenylhydrazine

Reaction was studied of 3,4-dihydroxyhexa-2,4-diene-1,6-dioic acid esters with 2,4-dinitrophenylhydrazine that led to the formation of esters of (3E)-3-[2-(2,4-dinitrophenyl)-hydrazinylidene]-4-oxohexane-1,6-dioic and (3E,4E)-3,4-bis[2-(2,4-dinitrophenyl)hydrazinylidene]-hexane-1,6-dioic acids. The structural features of compounds synthesized were established from the data of IR and NMR spectra and X-ray diffraction (XRD) analysis.     

Synthesis, structure, and physicochemical properties of dinuclear NiII complexes as highly efficient functional models of phosphohydrolases

As metal ions are present in the catalytic sites of several enzymes, attention has been focused on the synthesis and characterization of metal complexes able to act as biomimetic functional and structural models for these systems. In this study, a novel dinuclear NiII complex was synthesized, [Ni2(L2)(OAc)2(CH3CN)]BPh4 (2) (HL2=2-[N-(2-(pyridyl-2-yl)ethyl)(1-methylimidazol-2-yl)amin omethyl]-4-methyl-6-[N-(2-(imidazol-4-yl)ethyl)amino methyl]phenol), employing a new unsymmetrical dinucleating ligand containing N,O-donor groups as a model for hydrolases. Complex 2 was characterized by a variety of techniques including: elemental analysis, infrared and UV-vis spectroscopies, molar conductivity, electrochemistry, potentiometric titration, magnetochemistry, and single-crystal X-ray diffractometry. The structural and magnetochemical data of 2 allow us to consider this complex as a structural model for the active site of the ureases, as previously reported for [Ni2(L1)(OAc)2(H2O)]ClO4.H2O (1) (HL1=2-[N-bis-(2-pyridylmethyl)aminomethyl]-4-methyl-6-[N-(2-pyridylmethyl)aminomethyl] phenol). The characterization of complexes 1 and 2 (mainly by X-ray diffraction and potentiometric titration) led us to study their reactivities toward the hydrolysis of the substrate bis(2,4-dinitrophenyl)phosphate (2,4-BDNPP). These studies revealed that complexes 1 and 2 show the best catalytic activity reported so far, with acceleration rates 8.8x10(4) and 9.95x10(5) times faster, respectively, than the uncatalyzed hydrolysis of 2,4-BDNPP. Catalytic activity of 2 on 2,4-DNPP showed that the monoester is hydrolyzed 27 times slower than the 2,4-BDNPP diester under identical experimental conditions. Therefore, 1 and 2 can undoubtedly be considered highly efficient functional models of the phosphohydrolases.     

An efficient synthesis of cyclic IDP- and cyclic 8-bromo-IDP-carbocyclic-riboses using a modified Hata condensation method to form an intramolecular pyrophosphate linkage as a key step. An entry to a general method for the chemical synthesis of cyclic ADP-ribose analogues

An efficient synthesis of cyclic IDP-carbocyclic-ribose (3) and its 8-bromo derivative 6, as stable mimics of cyclic ADP-ribose, was achieved, and a condensation reaction with phenylthiophosphate-type substrate 15 or 16 to form an intramolecular pyrophosphate linkage was a key step. N-1-Carbocyclic-ribosylinosine derivative 28 and the corresponding 8-bromo congener 24 were prepared via condensation between N-1-(2,4-dinitrophenyl)inosine derivative 17 and a known optically active carbocyclic amine 18. Compounds 24 and 28 were then converted to the corresponding 5"-phosphoryl-5'-phenylthiophosphate derivatives 15 and 16, respectively, which were substrates for the condensation reaction to form an intramolecular pyrophosphate linkage. Treatment of 8-bromo substrate 15 with I2 or AgNO3 in the presence of molecular sieves 3A (MS 3A) in pyridine at room temperature gave the desired cyclic product 12 quantitatively, while the yield was quite low without MS. The similar reaction of 8-unsubstituted substrate 16 gave the corresponding cyclized product 32 in 81% yield. Acidic treatment of these cyclic pyrophosphates 12 and 32 readily gave the targets 6 and 3, respectively. This result suggests that the construction of N-1-substituted hypoxanthine nucleoside structures from N-1-(2,4-dinitrophenyl)inosine derivatives and the intramolecular condensation by activation of the phenylthiophosphate group with I2 or AgNO3/MS 3A combine to provide a very efficient route for the synthesis of analogues of cyclic ADP-ribose such as 3 and 6. Thus, this may be an entry to a general method for synthesizing biologically important cyclic nucleotides of this type.     

New approach for the synthesis of 1-aryl- and 1-heteroaryl-5-nitrouracil derivatives

1-(2,4-Dinitrophenyl)-5-nitrouracil and its 3-methyl derivatives were synthesized and used as substrates in reaction with aromatic amines and amino pyridines. In the reaction of aniline with 1-(2,4-dinitrophenyl)-5-nitrouracil, only the acyclic adduct was isolated. When 1-(2,4-dinitrophenyl)-3-methyl-5-nitrouracil was treated with aniline and other aromatic amines or amino pyridines, the desired 1-aryl-5-nitrouracil derivatives were obtained in satisfactory yield. The influence of the free H-3 proton present in the uracil ring on the course of the reaction is discussed.     

Theoretical Analysis of the Heterocyclic [4+2] Cycloaddition Between Pyridinium Ion and Enol Ether

Dearomative heterocyclic [4+2] cycloaddition between the N-(2,4-dinitrophenyl)pyridinium ion of nicotinamide and an enol ether was analyzed by Density Functional Theory (DFT) calculations. The calculation revealed that the reaction undergoes stepwise bond formation rather than occurring in a concerted manner. The experimental products were found to be both kinetically and thermodynamically favored. The calculated transition states and intermediate suggested that the high diastereoselectivity is derived from the electrostatic interaction between the 2-nitro group of the pyridinium ion and the hydrogen of the enol ether.     

5(4)-Chloro-1-(2,4-dinitrophenyl)pyrazoles from 2,4-Dinitrophenylhydrazones of Chlorovinyl Ketones and β,β-Dichloroacrolein

A method has been developed for obtaining 3-alkyl(phenyl)-4(5)-chloro-1-(2,4-dinitrophenyl)pyrazoles from appropriate dinitrophenylhydrazones of 1-chloro-, 1,2-, and 2,2-dichlorovinyl ketones by heating the latter in polyphosphoric acid. The structure of the pyrazoles was studied by IR and ¹H NMR spectroscopy. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1012–1019, July, 2005.     

Acid-catalyzed Conversions of N-(4-Nitrobenzylidene)-2-cyclopropyl- and N-(4-Nitrobenzylidene)-2-alkenylanilines. A new Method for the Synthesis of Dihydroquinolines and Quinolines

The acid-catalyzed conversions of N-(4-nitrobenzylidene)-2-cyclopropyl- and N-(4-nitrobenzylidene)-2-alkenylanilines have been studied. It has been established that the protonated azomethine unit of N-(4-nitrobenzylidene)-2-cyclopropylanilines is not capable of initiating intramolecular heterocyclization with participation of the three-membered ring. Conversion of N-(4-nitrobenzylidene)-2-(1-methylcyclopropyl)aniline to derivatives of quinoline is possible under the influence of concentrated H₂SO₄. Under the same conditions 2-methylcyclopropyl- and cyclopropyl-substituted Schiff's bases form only the corresponding alkenylazomethines (isomerization of the three-membered ring). Under the influence of more moderate acids (trifluoroacetic, polyphosphoric) N-(4-nitrobenzylidene)-2-propenyl- and N-(4-nitrobenzylidene)-2-buten-2-yl)anilines are converted to the corresponding dihydroquinolines and quinolines in high yields. N-(4-Nitrobenzylide! ne)- 2-(2,2-dimethylvinyl)aniline does not form derivatives of quinoline under the influence of the same acids in the given conditions.     

Kinetics and mechanism of the pyridinolysis of S-2,4-dinitrophenyl 4-substituted thiobenzoates

[reaction: see text] The reactions of S-2,4-dinitrophenyl 4-methyl (1), S-2,4-dinitrophenyl 4-H (2), S-2,4-dinitrophenyl 4-chloro (3), and S-2,4-dinitrophenyl 4-nitro (4) thiobenzoates with a structurally homogeneous series of pyridines are subjected to a kinetic investigation in 44 wt % ethanol-water, at 25.0 degrees C and an ionic strength of 0.2 M (KCl). The reactions are studied spectrophotometrically (420 nm) by monitoring the appearance of 2,4-dinitrobenzenethiolate anion. Pseudo-first-order rate coefficients (k(obsd)) are obtained for all the reactions, employing excess of amine. The plots of k(obsd) vs [free pyridine] at constant pH are linear with the slopes (k(N)) independent of pH. The Br?nsted-type plots (log k(N) vs pK(a) of the conjugate acid of the pyridines) are curved for all the reactions. The Br?nsted curves are in accordance with stepwise mechanisms, through a zwitterionic tetrahedral intermediate (T(+/-)), and a change in the rate-limiting step. An equation based on this hypothesis accounts well for the experimental points. The Br?nsted lines were calculated with the following parameters: Reactions of thiolbenzoate 1: beta(1) 0.33 (slope at high pK(a)), beta(2) 0.95 (slope at low pK(a)), and pK(a)(0) = 8.5 (pK(a) at the curvature center); thiolbenzoate 2: beta(1) 0.30, beta(2) 0.88, and pK(a)(0) = 8.9; thiolbenzoate 3: beta(1) 0.33, beta(2) 0.89, and pK(a)(0) = 9.5; thiolbenzoate 4: beta(1) 0.21, beta(2) 0.97, and pK(a)(0) = 9.9. The increase of the pK(a)(0) value with the increase of the electron-withdrawing effect of the acyl substituent is explained by the argument that the rate of pyridine expulsion from T(+/-) (k(-)(1)) is favored over that of 2,4-dinitrobenzenethiolate leaving (k(2)), i.e., k(-)(1)/k(2) increases, as the acyl group becomes more electron withdrawing. The pK(a)(0) values for the title reactions are smaller than those for the reactions of the corresponding 4-nitrophenyl 4-substituted thiolbenzoates with the same pyridine series. This is explained by the larger k(2) value for 2,4-dinitrobenzenethiolate leaving from T(+/-) compared with 4-nitrobenzenethiolate, which results in lower k(-)(1)/k(2) ratios for the dinitro derivatives. The pK(a)(0) value obtained for the pyridinolysis of thiolbenzoate 2 (pK(a)(0) = 8.9) is smaller than that found for the same aminolysis of 2,4-dinitrophenyl benzoate (pK(a)(0) = 9.5). This is attributed to the greater nucleofugality from T(+/-) of 2,4-dinitrobenzenethiolate (pK(a) of conjugate acid 3.4) relative to 2,4-dinitrophenoxide (pK(a) of conjugate acid 4.1). The title reactions are also compared with the aminolysis of similar esters to assess the effect of the amine nature and leaving and acyl groups on the kinetics and mechanism.     

An Explosive Organic／Inorganic Hybrid： Synthesis and Thermal Property of Octa （2,4-dinitrophenyl） silsesquioxane

Octaphenylsilsesquioxane (OPhS) was prepared by a modifying method and a new core-shell nanocomposite, octa(2,4-dinitrophenyt)sitsesquioxane, [(R2PhSiO1.5)8, R=-NO2, ODNPhS], was synthesized by nitration of OPhS in a mixed acid solution of nitric and sulfuric acids at about 60℃. Their molecular structures were determined by DRIFTS, ^1H NMR, ^13C NMR spectra analysis. The thermal analysis shows that ODNPhS is an explosive that detonates at about 420℃.     

Circular dichroism of N-2,4-dinitrophenyl derivatives of chiral 1-alkyl-2-propynylamines and 1-alkyl-2-propenylamines

The sign of the Cotton effects near 320 and 400 nm in the CD spectra of the N-2,4-dinitrophenyl derivatives of chiral 1-alkyl-2-propynylamines and 1-alkyl-2-propenylamines correlates with their absolute configurations. The Cotton effects are generated by the coupled oscillator methanism and their sign is the same as the chirality (right-handed screw for positive chirality) of the interaction of the dominant oscillators of the 2,4-dinitrophenylamino chromophore with that of the amine moiety, the chirality of the interaction being deduced by conformational analysis.     

2-[2-(4,6-二甲基)-嘧啶基]-4-苯基-1,2,4-噁二唑烷-3,5-二酮的合成

异氰酸苯醇和N-[2-(4,6-二甲基)-嘧啶基]-羟胺(5)反应生成1-[2-(4,6-二甲基)-嘧啶基]-1-羟基-3-苯基脲(6)。化合物(6)在三乙胺存在下和氯甲酸乙醇反应生成2-[2-(4,6-二甲基)-嘧啶基]-4-苯基-1,2,4-噁二唑烷-3,5-二酮(1)。