Showing papers on "Hydrazone published in 2001"

Synthesis and Pharmacological Activities of Hydrazones, Schiff and Mannich Bases of Isatin Derivatives

Abstract: Schiff bases and phenyl hydrazone of isatins were prepared by reacting isatin and the appropriate aromatic primary amine/hydrazines. A new series of the corresponding N-mannich bases were synthesized by reacting them with formaldehyde and diphenylamine. The chemical structures were confirmed by means of their 1H-NMR, IR spectral data and elemental analysis. The compounds were screened for analgesic, antiinflammatory and antipyretic activity. 1-Diphenylaminomethyl-3-(1-naphthylimino)-1,3-dihydroindol-3-one (4), 3-(1-naphthylimino)-5-bromo-1,3-dihydroindol-2-one (2) and 1-diphenylaminomethyl-3-(4-methylphenylimino)-1,3-dihydroindol-3-one (7) were found to exhibit the highest analgesic, anti-inflammatory and antipyretic activity respectively. 1-Diphenylaminomethyl-3-(4-methylphenylimino)-1,3-dihydroindol-3-one (7) was found to be the most active compound of the series.

Dioxo- and Oxovanadium(V) Complexes of Biomimetic Hydrazone ONO Donor Ligands: Synthesis, Characterisation, and Reactivity

Abstract: The dioxovanadium(V) complexes M[VO2(L)solv] (2, 5, 6) have been isolated along with dimeric, oxo-bridged monooxovanadium complexes with the formula [{VOL}2µ-O] (1, 4), and characterised by their spectral and thermogravimetric properties and reactivity patterns. H2L is the hydrazone H2{(R-sal)-iNH} [sal derives from salicylaldehyde (R = H) or p-Cl-salicylaldehyde (R = Cl)] or H2hap-iNH, where hap is the o-hydroxyacetophenone moiety, and iNH stands for isonicotinic acid hydrazide. In the isolated potassium (M = K) complexes 2a, 5 and 6, solv is a water molecule, which was exchanged for methanol or DMSO in the respective solutions as shown by 51V NMR. Treatment of the dimeric (1 and 4) or anionic complexes (2a and 5) with H2O2 yielded (unstable) oxoperoxovanadium complexes K[VO(O2)L] (7, 8). Acidification of 1 and 4 afforded oxohydroxo complexes. When compound 2a is dissolved in methanol, it is partly deoxygenated to form [VO(OMe)(HOMe)L] (9), the crystal and molecular structures of which have been determined, confirming the ONO binding mode of L in its enolate form.

Palladium-catalyzed allylic alkylation using chiral hydrazones as ligands.

Abstract: Palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate (4) with a dimethyl malonate−BSA−LiOAc system and its derivatives has been successfully carried out in the presence of a new chiral hydrazone ligands such as 2-(diphenylphosphino)benzaldehyde SAMP hydrazone (DPPBA-SAMP) (3a) in high yields with high enantioselectives.

Tartric acid-based linker for the solid-phase synthesis of C-terminal peptide alpha-oxo aldehydes.

Abstract: A novel linker, based on the anchoring of (+)-dimethyl 2,3-O-isopropylidene-D-tartrate to PEGA or PEG-PS solid supports, was developed for the solid-phase synthesis of C-terminal peptide alpha-oxo aldehydes. Peptide elongation was performed using the 9-fluorenylmethoxycarbonyl/t-Bu chemistry. The peptide and the 1,2-diol were deprotected on the solid phase. Then, a periodic oxidation of the fully deprotected peptidyl-resin led to the simultaneous cleavage of the product from the solid support and to the generation of the alpha-oxo aldehyde moiety. The methodology allowed the distance between the alpha-oxo aldehyde and the peptide to be easily modulated. The C-terminal peptide alpha-oxo aldehydes synthesized in this study were found to be useful partners in hydrazone, thiazolidine, and oxime chemical ligations.

Synthetic and biological studies on coumarin hydrazone derivatives

Abstract: The reaction of both of coumarin and 6-nitrocoumarin hydrazones (1,4) with alkyl(aryl)isothiocyanate afforded the corresponding 3-N[alkyl(aryl)thioamido] coumarins 3a-d or benzopyrano[2,3-c]pyrazole-3-thione derivatives 6a-d , respectively. Compounds (3a-d) were used as key intermediates for the preparation of benzopyrano-pyridine derivatives (7a-d & 10a) or benzopyranoazepine derivatives 8a,c & 12a-d through the reaction with different acyl halides or ethoxymethylenemalononitriles and subsequent cyclization. Biological activity of some new compounds against Gram +ve and Gram -ve were given.

Synthesis, Acidity Constants and Tautomeric Structure of 7-Arylhydrazono[1,2,4]Triazolo[3,4-b][1,3,4]thiadiazines in Ground and Excited States

Abstract: 7-Arylhydrazono[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines 4 were synthesized from the reactions of 4-amino-5-phenyl-4H-[1,2,4]triazole-3-thiol 2 and 2-(2-naphthyl)-2-oxoethanehydrazonoyl bromides 1 and their acid dissociation constants pK and pK*, in the ground and excited states, respectively, were determined. Both pK and pK* constants were correlated by Hammett equation. The pK and the spectral data presented indicate that the title compounds exist predominantly in the hydrazone tautomeric form.

Synthesis and potential antimicrobial activity of some new compounds containing the pyrazol-3-one moiety

Abstract: Pyrazolone derivative 3 was prepared by the nucleophilic addition of 2,5-diphenyl-2,4-dihydro-3H-pyrazol-3-one (1) to chalcone (2). Reaction of 3 with hydrazine hydrate, phenylhydrazine, hydroxylamine hydrochloride, p-chlorobenzaldehyde, acetyl chloride and phosphorus pentasulfide afforded the corresponding hydrazone, phenylhydrazone, oxime, arylidene, O-acetyl and dithio derivatives. Pyrazolone 1 was condensed also with cyclohexanone and aromatic aldehydes; the behaviour of the obtained arylidene derivatives towards hydrazines, cyclohexanone, malononitrile and urea was also investigated. Some of the new compounds showed antimicrobial and antifungal activities.

Stereoselective Nucleophilic Formylation and Cyanation of α-Alkoxy- and α-Aminoaldehydes

Abstract: The spontaneous 1,2-addition of formaldehyde N,N-dialkylhydrazones to carbohydrate-derived α-alkoxyaldehydes takes place under neutral conditions and in the absence of catalysts or promoters to afford the corresponding α-hydroxyhydrazones in good to excellent yields and with highly anti diastereoselectivities. Subsequent transformations of the hydrazono group into aldehydes and nitriles following known procedures provide a new entry into the homologation of carbohydrates and the synthesis of cyanohydrins, respectively. Additionally, reaction of methyleneaminopyrrolidine with N-Boc-protected α-aminoaldehydes from natural amino acids efficiently affords the corresponding adducts under the same conditions. From these adducts, a variety of biologically interesting α-hydroxy-β-aminocarbonyl compounds can be accessed upon manipulation of the hydrazone moiety.

On the Synthesis and Reactions of Indole-2-carboxylic Acid Hydrazide

Abstract: Indole-2-carboxylic acid hydrazide was prepared and allowed to react with aromatic aldehydes in acidic medium to give the corresponding hydrazone derivatives in good yields. The hydrazones were cyclized to indolo[2,3-d]pyridazine derivatives by refluxing with acetyl chloride. The indole carbohydrazide was converted to 2-triazolylindoles which acted as starting materials for several indole derivatives. A number of new indole derivatives were also prepared and structurally confirmed.

Thermal analysis in structural characterization of hydrazone ligands and their complexes

Abstract: Results of our research on synthesis and characterization of complexes with acylhydrazone derivatives are described in this review paper. Structural characterization of newly synthesized complexes by thermal analysis (TG, DTA, DSC) is particularly emphasized in this paper. Thermal analysis enabled us to study not only structural changes of substances during thermal treatment, but also the mode of coordination and degree of deprotonation of acylhydrazones, as well as geometry of the coordination sphere of complexes, the structure of which had not been determined by X-ray analysis. Topics in this paper are as follows: complexes of dioxomolybdenum(VI) with tridentate hydrazones, usnic acid derivatives and their Cu(II) complexes, as well as transition metal complexes with 2,6-diacetylpyridine bis(hydrazones).

Solid-to-solid Reaction of 2,4-Dinitrophenylhydrazine with Several Aromatic Aldehydes Bearing Electron-donating Groups

Abstract: Aromatic 2,4-dinitrophenylhydrazones are conveniently prepared from 2,4-dinitrophenylhydrazyne and the corresponding aldehydes bearing electron-donating groups [N(Me)2, OMe and OH] in non-solvent reactions. The high-dilution method in the absence of basic or acidic catalysts is also efficient. According to X-ray data, planar conformation of the hydrazone molecules is stabilized by intramolecular NH…O2N hydrogen bond. Formation of 2D networks in the crystal is mediated via intermolecular CH…O2N hydrogen bonds.

Preparation of α-(2,2-Diphenylhydrazino)lactones and Related Compounds by Radical Cyclization: Use of Glyoxylic Acid Hydrazone Derivatives

Abstract: Glyoxylic acid diphenylhydrazone (2a) and the corresponding O-benzyloxime (2b) are easily esterified in high yield by β-bromo alcohols. The resulting esters undergo radical cyclization to α-(2,2-diphenylhydrazino)- or α-[(phenylmethoxy)amino]lactones on treatment with tributyltin hydride. Esters for radical cyclization were also made using a β-(phenylseleno) alcohol and an enol ether. Several derivatives of glyoxylic acid were evaluated, but none was as effective as 2a or 2b. The imine 28 was prepared by an indirect route; it undergoes radical cyclization with displacement of the nitrogen substituent (28 → 30) so that an α-amino lactone can be generated by acid hydrolysis of the cyclization product.

Synthesis and structure–activity relationships of benzophenone hydrazone derivatives with insecticidal activity

Abstract: A broad range of benzophenone hydrazone derivatives was prepared and tested against selected chewing insect pests, allowing the analysis of structure-activity relationships. Good activity was found only when the aromatic rings were substituted at the 4-positions with an halogen atom and a triflate or perhaloalkoxy group. In contrast, a number of substituents on the hydrazone part led to active compounds, the best results being achieved with acyl-type substituents. The excellent laboratory and greenhouse activity of the best representatives was confirmed in semi-field trials against Spodoptera littoralis.

Synthesis and Nonlinear Optical Properties of a New Syndioregic Main-Chain Hydrazone Polymer

Abstract: The synthesis of a syndioregic main-chain hydrazone nonlinear optical polymer is reported. The nonlinearity is thermally stable up to 140 °C and retains 90% of the original value even when stored at 100 °C for 100 h. The polymer has a relatively low nonlinearity (d33 = 3.6 pm/V) due to the incorporation of a low β chromophore.

Method for producing hydrazine derivative

Abstract: The present invention provides a method for producing a hydrazine derivative of the formula [2]: wherein R1 is alkyl group having 1-12 carbon atoms and the like, R2 is alkyl group having 1-12 carbon atoms and the like, and Ar is phenylene group and the like, from a hydrazone derivative of the formula [1] wherein R1, R2 and Ar are as defined above, in the presence of at least one base selected from the group consisting of an organic base and an inorganic base, and a metal hydrogenating catalyst. By this method, reduction proceeds selectively and a hydrogenolysis reaction (side reaction) can be suppressed.

Synthesis of Some Potentially Bioactive Compounds From Visnaginone

Abstract: The reaction of 5-acetyl-6-hydroxy-4-methoxybenzo[b]furan (visnaginone Ia) with 2-diethylaminoethylchloride led to the formation of 5-acetyl-6-diethylamino-ethoxy-4-methoxybenzo[b]furan (II), whereas condensation of compound II with some aromatic aldehydes afforded the corresponding chalcones IIIa-c. Methylation of visnaginone (Ia) gave 5-acetyl-4,6-dimethoxybenzo[b]furan (Ib), which in turn reacted with some aromatic aldehydes to give the corresponding chalcones IIId,e. The reaction of chalcones IIId,e with hydrazine hydrate in alcohol gave the pyrazoline derivatives IVa,b, whereas when the same reaction was carried out in acetic acid it afforded the N-acetylpyrazoline derivatives Va,b. Similarly, the reaction of IIId,e with phenyl hydrazine in acetic acid led to the formation of phenylpyrazoline derivatives VIa,b, whereas condensation of chalcones IIId,e with hydroxyl amine hydrochloride gave the isoxazoline derivatives VIIa,b. The reaction of compound II with phenylhydrazine and 2,4,6-trichlorophenylhydrazine afforded the corresponding phenyl hydrazone derivatives VIIIa,b. Mannich bases IXa,b were synthesized by the reaction of visnaginone (Ia) with piperidine and benzylamine in the presence of formaline.

SYNTHESIS AND CHARACTERIZATION OF NEW Cu(II) COMPLEXES DERIVED FROM BENZILIC AND MANDELIC HYDRAZONES

Abstract: Two new sets of Cu(II) complexes with newly synthesised benzilic and mandelic hydrazone derivatives were prepared in the mole ratios 1:1 and 1:2 (Cu:L). The structure of the complexes was identified on the basis of the data obtained from elemental and thermal analyses as well as IR, UV-visible, ESR spectra, and X-ray diffraction. The results indicate that the ligands are tightly bound to the metal ion through the phenolic OH oxygen, the azomethine nitrogen, and the enolic OH oxygen in case of the 1:1 complexes while for the 1:2 complexes the enolic OH group did not participate in bonding. The complexes have elongated octahedral as well as square-planar symmetries.

Synthesis and characterization of two new aryl cyclobutyl ketoethyl methacrylate monomers and their polymers

Abstract: Two new methacrylate monomers, 2-[3-(6-tetralino)-3-methylcyclobutyl]-2-ketoethyl methacrylate (TKEMA) and 2-(3-mesityl-3-methylcyclobutyl)-2-ketoethyl methacrylate (MKEMA), were obtained from the reaction of 1-chloroacetyl-3-methyl-3-arylcyclobutane with sodium methacrylate. The oxime and hydrazone derivatives of poly(TKEMA) and poly(MKEMA) were prepared with hydroxylamine and 2,4-dinitrophenyl hydrazine. Poly(TKEMA) and poly(MKEMA), their oxime and hydrazone derivatives, and the monomers were characterized with Fourier transform infrared and NMR techniques. The glass-transition temperatures and thermal stability of the polymers and their oxime and hydrazone derivatives were compared. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4167–4173, 2001

Synthesis and reactions of chiral clusters containing an SRuCoMo core

Abstract: In order to resolve tetrahedron-type chiral clusters, three chiral clusters containing a functionally substituted cyclopentadienyl ligand were prepared, and the reactions of functional substituents were investigated. The ester group was hard to hydrolyze while hydrazide can easily condense with the ketonic carbonyl on the cyclopentadienyl ring to form a cluster hydrazone. Two optically active auxiliaries have been attached to the chiral framework; however, the diastereoisomers cannot be separated by silica gel chromatography. Their presence was established by 13C NMR spectra.

Synthesis and application of 4-(N,N-dimethylaminosulfonyl)-7-N-methylhydrazino-2,1,3-benzoxadiazole (MDBDH) as a new derivatizing agent for aldehydes.

Abstract: In a five step synthesis, 4-(N,N-dimethylaminosulfonyl)-7-N-methylhydrazino-2,1,3-benzoxadiazole (MDBDH) was prepared in high yields as a stable new derivatizing agent for carbonyl compounds. Reagent and derivatives have not been described in literature before. Major advantage of this substance compared with similar reagents is its improved solubility in polar solvents, e.g. methanol and ethanol. MDBDH reacts with aldehydes in the presence of an acidic catalyst under formation of the corresponding hydrazones. These are separated by means of reversed-phase liquid chromatography and detected UV/vis spectroscopically at wavelengths around 450 nm, depending on the individual hydrazone. MDBDH reacts with oxidizers as nitrogen dioxide and nitrite to only one product, 4-(N,N-dimethylaminosulfonyl)-7-methylamino-2,1,3-benzoxadiazole (MDBDA), which can easily be separated from the hydrazones of lower aldehydes. Due to large molar absorptivities and absorption maxima at wavelengths > 430 nm, limits of detection range from 4 x 10(-8) to 6 x 10(-8) mol.L-1, and limits of quantification range from 1 x 10(-7) to 2 x 10(-7) mol.L-1 for the individual hydrazones. The method was applied to the determination of aldehydes in automobile exhaust.

Synthesis of Some New Spiro, Isolated and Fused Heterocycles Based on 1H‐indole‐2‐One

Abstract: The reaction of 3-benzoylcyanomethylidine-1(H)-indole-2-one (1) with a variety of active methylene compounds, thioglycolic acid, glycine, hydrazine hydrate and phenyl hydrazine led to the formation of compounds 4a-d-10 3-Thiosemicarbazide-1(H)-indole-2-one 2 on reaction with α-halocarbonyl compounds gave compounds 11a-c, 12a-c The latter compounds on heating with phosphoryl chloride, cyclization takes place via losing water to give the angular tetracyclic compounds 13a,b and 14a-c Cyanoacetic hydrazone derivative 3 readily cyclized upon heating in triethyl orthoformate to give the tricyclic system, oxopyridazino indole 15 On the other hand, the reaction of 3 with benzylidine malononitrile and benzylidene ethylcyanoactate gave the pyranyl hydrazone derivatives 16a,b

Reaction of 1,5-Diphenyl-1,4-pentadien-3-one and 1,5-Diphenyl- 1-penten-4-yn-3-one with Monosubstituted Hydrazines

Abstract: Phenyl- and isopropylhydrazines react with 1,5-diphenyl-1,4-pentadien-3-one to give 4,5,6,7-tetrahydroindazole derivatives instead of the expected 4,5-dihydropyrazoles. The reaction of phenylhydrazine with 1,5-diphenyl-1-penten-4-yn-3-one leads to formation of 1,5-diphenyl-3-phenylethynyl-4,5-dihydropyrazole. 2,4-Dinitrophenylhydrazine reacts with 1,5-diphenyl-1-penten-4-yn-3-one, affording the corresponding unsaturated hydrazone rather than pyrazole derivative.

The reaction of digitoxin and digoxin with cyanoacetic acid hydrazide: synthesis of coumarin, thiazole, thiophene and pyridine derivatives with potential biological activities.

Abstract: The reaction of either Digitoxin or Digoxin with cyanoacetic acid hydrazide gave the hydrazone derivatives3a and3b respectively. The reactivity of the latter products towards chemical reagents was studied to give heterocyclic derivatives with potential biological activities.