Pyrazolinone Ring Research Articles

Synthesis, Characterization and Antimicrobial Study of nickel(II),palladium(II),platinum(II),rhodium(III), cadmium(II) and zirconium(IV) complexes with (E)-1-(benzo[d]thiazol-2-yl)-4-(hydroxy(2-hydroxyphenyl)methylene)-3-methyl-1H-pyrazol-5(4H)-one

New transition metal complexes of (E)-1-(benzo[d]thiazol-2-yl)-4-(hydroxy(2-hydroxyphenyl)methylene)-3-methyl-1H-pyrazol-5(4H)-one was prepared and their structures and formulas were confirmed by elemental analyses, EIMS, FT-IR and NMR spectra. The ligand (LH) was prepared through the ring closure of 2-hydrazino benzothiazole and 3-acetyl- 4-hydroxy cumarine in dry methanol. The complexes of nickel(II), palladium (II), platinum(IV), cadmium(II), rhodium(III) and zirconium(IV) were isolated in solid state up on the direct reaction of their hydrated chlorides or nickel(II) nitrate with the free ligand solution. The solid structures of metal complexes were supported on the basis of elemental analyses, IR, UV-Visible spectra, as well as the molar conductivity and magnetic susceptibility.The thermal analyses of TG-DSC were done for the LH ligand and their rhodium(III) and palladium(II) complexes in argon atmosphere in order to conclude their structures and thermal stability and the thermo grams observed for the studied compounds have revealed the proposed structures. The data found from preliminary studies revealed that the nickel(II), palladium(II) and platinum(II) were square planner geometry in [MLCl(H2O)] formual, M= Ni, Pd, Pt(II), whereas the rhodium(III), zinc(II) and cadmium(II) were octahedral and tetrahedral geometry respectively in the formulas, [RhL2(H2O)2]Cl and [MLCl(H2O)], M=Zn and Cd(II) ions. However the zirconium(IV) complex was square pyramid with five-coordination number,[ZrOL2]. The H NMR spectra of the cadmium(II) and platinum(II) complexes exhibited remarkable changes in the peaks of -NH- pyrazolinone ring and much less shifts in the other functional groups of phenolic and aromatic moiety indicating that the the active sites of coordination with the metal ions are the nitrogen atom of benzothiazole ring and the hydroxyl group linked at C3 at C3 of pyrazole ring. The biological activity of the solutions of the prepared compounds in DMSO as control was estimated against some positive and negative gram bacteria and the inhibition zone measured by diffusion method showed that the metal complexes have greater activity in their spectrum of antibiotics in compared with the employed standard drug in 20 ppm concentarations.

Fenton, Photo-Fenton, H2O2 Photolysis, and TiO2 Photocatalysis for Dipyrone Oxidation: Drug Removal, Mineralization, Biodegradability, and Degradation Mechanism

Dipyrone (DIPY), an analgesic drug, is very quickly hydrolyzed to 4-methylaminoantipyrine (4-MAA) in an acidic solution. Batch study was conducted to compare the performance of different oxidation processes such as Fenton (FP), photo-Fenton (PFP), UV/H2O2 photolysis (UVP), and UV/TiO2 photocatalysis (UVPC) for removal of 4-MAA from aqueous solution. The degradation efficiency was evaluated in terms of total organic carbon (TOC) reduction and enhancement of biodegradability. Maximum 4-MAA removals of 94.1, 96.4, 74.4, and 71.2% were achieved in FP, PFP, UCP, and UVPC, respectively, against mineralization of 49.3, 58.2, 47, and 24.6%. The proposed mechanisms suggest that the cleavage of three methyl moieties followed by pyrazolinone ring breakage led to formation of various intermediates with low errors (−0.88 to 0.11 g/mol). The intermediates primarily were hydroxylated and carboxylic derivatives. BOD5 to COD (BOD, biochemical oxygen demand; COD, chemical oxygen demand) ratio of ≥0.4 resulted from DIPY dec...

Synthesis and Antimicrobial Evaluation of Novel Pyrazolones and Pyrazolone Nucleosides

The synthesis of a novel series of 4-arylhydrazono-5-methyl-1,2-dihydropyrazol-3-ones 4a–h, and their N 2-alkyl and acyclo, glucopyranosyl, and ribofuranosyl derivatives is described. K2CO3 catalyzed alkylation of 4a–h with allyl bromide, propargyl bromide, 4-bromobutyl acetate, 2-acetoxyethoxymethyl bromide, and 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide proceeded selectively at the N 2-position of the pyrazolinone ring. Glycosylation of 4a with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose under Vorbruggen glycosylation conditions gave the corresponding N 2-4-arylhydrazonopyrazolone ribofuranoside 9a in good yield. Conventional deprotection of the acetyl protected nucleosides furnished the corresponding 4-arylhydrazonopyrazolone nucleosides in good yields. Selected numbers of the newly synthesized compounds were screened for antimicrobial activity. Compounds 4b, 12a, and 14d showed moderate activities against Aspergillus flavus, Penicillium sp., and Escherichia coli.

Characterization of oxalic acid derivatives as new metabolites of metamizol (dipyrone) in incubated hen's egg and human

Metamizol (dipyrone, 1), a widely used drug with effective analgesic and antispasmodic properties, shows severe side effects like agranulocytosis and anaphylactic shock reactions, the reasons of which are not known until today. After oral administration 1 is completely metabolized. All hitherto known metabolites have an intact pyrazolinone ring structure like the parent compound and are completely extractable from urine with polar organic solvents. However, only a fractional amount of the applied dosage can be recovered by this procedure. To clarify the reason of this deficit of unknown metabolites we followed the hypothesis of oxidative rupture of the heterocyclic ring during metabolism of 1. On the basis of former in vitro results we now were able to identify in quality three oxalic acid derivatives and one acetic acid phenylhydrazide as new metabolites of metamizol in the allantoic fluid (AF) of incubated hen's eggs as well as in human urine by means of GC–MS analysis and comparison with unequivocally synthesized authentic reference compounds. Whereas the oxamazide 7, the phenylhydrazide 8 and N-methyloxamic acid 9 are only present in trace concentrations and therefore cannot account for the deficit in the balance of metabolites, the oxalic acid monohydrazide 11 seems to be excreted in higher amount. But quantitative determination of this new metabolite would be required to answer the open questions concerning the biotransformation of metamizol and thereby to detect new facts about mode of action and side effects of this drug.

Pyrazolinon‐Ringschluß unter Alkoxywanderung

Pyrazolinone Ring Closure with Alkoxy MigrationAlkyl 3‐(4‐nitro‐phenylazo)‐2‐brom‐2‐butenoates (1a, b) with morpholine undergo substitution of the bromo group and ring closure connected with a migration of the alkoxy group forming 4‐alkoxy‐3‐methyl‐4‐morpholino‐1‐(4‐nitro‐phenyl)pyrazolin‐5‐ones (2a, b).

Synthesis of 3‐(2‐chloro‐5‐nitroanilino and 4‐nitroanilino)‐1‐(2,4,6‐trichlorophenyl)‐2‐pyrazolin‐5‐ones

AbstractA new synthesis of 3‐anilino‐1‐aryl‐2‐pyrazolin‐5‐ones in which the pyrazolinone ring is built via NN bond formation is described. 2‐Cyano‐2′,4′,6′‐trichloroacetanilide 1 was converted to imino ether hydrochloride 2 which was reacted with anilines in methanol to produce N‐arylimino ether 3a,b. Reaction of these N‐arylimino ethers with hydroxylamine gave N‐arylamidoximes 4a,b. An 1,2,4‐oxadiazol‐5‐one 6a was prepared from the N‐arylamidoxime 4a and subjected to base‐induced rearrangement. The desired 3‐anilino‐pyrazolinone 7a was obtained only in a very low yield. However, O‐acetylation of the N‐arylamidoximes 4a,b followed by acid‐catalyzed ring closure and rearrangement in the presence of excess acetic anhydride gave a mixture of N‐acetylanilinopyrazolinones (e.g. 10) and 4‐acetyloxy‐3‐N‐acetylanilinopyrazoles (e.g. 12) which upon acid hydrolysis afforded the 3‐anilinopyrazolinones 7a,b in better yield.

Generation and characterization of carbonyl ylides from pyrazolinone spirooxiranes

Laser flash photolyses of 1-oxa-5,6-diazaspiro[2.4]hept-6-ene-4-onesI (Ar ≡ Ph, p-NO2Ph, p-CH3OPh; R1 ≡ CH3, Ph; R2, R3 ≡ CH3; R2 ≡ Ph, p-NO2Ph, p-ClPh, 2-naphthyl; R3 ≡ H) and of the symmetrical oxiraneII give rise to transients with absorption spectra in the visible region and lifetimes of the order of 0.3 – 10 μs in benzene at room temperature. Sensitization experiments in some cases indicate that the intermediate may arise from a triplet as well as a singlet excited state. Transients fromI are quenched by alcohols and 2,3-dimethyl-2-butene whereas that fromII is not. Steady state photolyses ofI in methanol give products consistent with the assignment of the structure of the transient as a carbonyl ylide incorporating the pyrazolinone ring.

Pyrazolinone carbonyl ylides: novel photochemistry of oxiran and diazo-compounds

A series of oxopyrazoline-4-spiro-oxirans and 4-diazo-3-methyl-1-phenyl-5-oxo-2-pyrazoline have been photolysed to generate reactive intermediates incorporating the pyrazolinone ring, which have been trapped with nucleophilic solvents and investigated by spectroscopic techniques.

Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 7. Mitteilung. Thio‐ und Dithiophosphorsäureester von der Art des GS 13005 mit einem analogen oder homologen heterocyclischen Ring

AbstractTo complete results presented in this and in previous papers of this series as well as published in patents of other authors a review is given on known and new variations of the heterocyclic moiety in GS 13005 type thio‐ and dithiophosphoric acid esters (1, 2) by modification of the 1,3,4‐thiadiazol‐2(3H)‐one ring 5 and by its replacement by analogue five‐ and homologue six‐membered rings.Among new esters of this type some containing the pyrazolinone ring 3 or a 2‐alkoxy‐4H, 6H‐1,3,4‐thiadiazin‐5‐one ring 10 (homologue of the original 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐one ring in GS 13005) show no remarkable pesticidal activity, some others containing a pyrazolering 7 or a 3(2H)‐pyridazinonc ring 8 are moderately to highly active but toxic to inauinials in the same proportion.Attempts to prepare seven‐membered 2‐alkoxy‐ and 2‐alkylthio‐6,7‐dihydro‐l, 3,4‐thiadiazepin‐S(4H)‐ones 11, Z‐rnethoxy‐l,3,4‐thiadiazepin‐S(4H)‐one 12 (ring vinylogue of the original 5‐methoxy‐l,3,4‐thiadIazol‐2(3H)‐one ring in GS 13005) and its 7‐methyl‐derivative have been unsuccessful due to unexpected side reactions, such as: five‐ring closure of 3‐(3‐chloropropionyl)‐thio‐ and ‐dithiocarbazic acid esters 22 to pyrazolidinone derivatives 23, pyrazolinone ring closure of a 3‐(acetoacety1)‐thiocarbazic acid O‐methyl ester derivative 26, bromine attack on sulfur in 3‐(2‐alkenoyl)‐thiocarbazic O‐methyl esters 29 instead of bromine addition at the double bond, and halogen splitting off without ring closure in 3‐(2,3‐dihalogeno‐alkanoyl) ‐thiocarbazic O‐methyl esters 30 prepared by acylation of thiocarbazic acid O‐methyl ester with dihalogeno‐alkanoyl‐chlorides.

The crystal structures of two pyrazolinone azomethine dyes

Pyrazolinone azomethine dyes are important as image formers in color photography. Usually these dyes are magenta in hue, but when they are overcrowded by suitable substituents, their absorption shifts bathochromically and they are cyan. The structures of two of these dyes the relatively uncrowded 4-(4-N,N-diethylaminophenylimino)-3-methyl-l-phenyl-2-pyrazolin-5-one (UPAD) and the highly hindered 4-(2,6-dimethyl-4-N, N-diethylaminophenylimino)-3-methyl-l-phenyl-2-pyrazolin-5-one (HPAD)have been determined from single-crystal X-ray diffraction data. UPAD is monoclinic, P21/n, with a= 11.840 ( ~ b = 12.748 (2), c= 11-982 (2) A, fl=93.02 (1) ° and Z=4; HPAD is triclinic, P1, with a=9-114 (1) , 13-657 (1), c=8-502 (1),~, e= 10319 (1), fl= 102-92 (1), y=9163 (1) , and Z= 2. The structures were solved by direct methods and refined by least squares. The hydrogen atoms were located from difference Fourier syntheses and were refined. The final R value for HPAD is 0.042 and for UPAD is 0.054. Neither dye is planar but HPAD deviates considerably more from planarity than UPAD. The dihedral angle between the pyrazolinone ring and the p-phenylenediamine ring is 13.9 ° for UPAD and 56.6 ° for HPAD. The bond lengths show that the unexcited canonical structure is the dominant contributor to the conjugation and that the quinoid form of the p-phenylenediamine part is more important for UPAD than for HPAD. A striking feature of the structure of UPAD is the presence of a definite intramolecular C-H. • • O hydrogen bond. The atomic separations are O. • • H = 2.03/~, O. • • C = 2.95/~. Infrared data show that the C=O stretch frequency is 24 cm -1 less for UPAD than for HPAD.

Metabolism of drugs. LXX. Further study on antipyrine metabolism.

In the previous paper, it was shown that antipyrine was oxidized not only to 4-hydroxyantipyrine, but also to 3-hydroxymethyl-2-methyl-1-phenyl-3-pyrazolin-5-one which was characterized on the basis of analytical and spectral data. The present study established the latter pathway, the oxidation of methyl group at 3-position of pyrazolinone ring by the chemical synthesis of authentic sample, and also demonstrated chromatographically the subsequent pathway to 2-methyl-1-phenyl-5-oxo-3-pyrazolin-3-carboxylic acid. Possible importance of this serial oxidation steps was discussed concerning with antipyrine allergy problem. By the preliminary test it was shown that 3-hydroxymethyl metabolite did not retain the antipyretic acitivity.

Infrared Analysis of 2-Pyrazolin-5-one Derivatives

The ir spectra in the region 4000–250 cm−1 in the solid state have been recorded for seventy-six 1,3-disubstituted 2-pyrazolin-5-ones in which 4-positions are coupled with various diazotized anilines. Correlations between structure and frequency are made. From the results obtained, a useful application of these spectral correlations can be derived for recognizing a pyrazolinone dye in an unknown compound by means of its spectrum. The strong bands at about 1650, 1550, 1340, 1260, and 1150 cm−1, and sometimes the strong or medium bands near 1000 and 680 cm−1 constitute a good indication of the presence of a 4-arylhydrazono pyrazolinone ring.

Spectroscopic Studies on 2-Pyrazolin-5-one Dyes

Abstract The spectra of forty-five 2-pyrazolin-5-one dyes in the ultraviolet and visible regions are discussed on the basis of their hydrazone-keto structures. In particular, the effects of sterically-sensitive ortho-substitutions in the 1- and 4-positions on the pyrazolinone ring are investigated. The bathochromic effects on the visible absorption band of pyrazolinone dyes are caused by electron-attracting substituents in the 3-position, not by 1- and 4-substituents.