- Conductance studies on complex formation of nano Cu(NO3)2.2.5H2O with 4,6-diacetylresorcinol in mixed solvents
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The different complexation thermodynamic parameters for example, formation constants (Kf), free energies of formation (?Gf), enthalpies of formation (?Hf) and entropies of formation (?Sf) for nano copper nitrate hemi pentahydrate (Cu(NO3)2.2.5H2O) with 4,6-diacetylresorcinol as a ligand in pure DMF and in mixed solvents of DMF and water are calculated at different temperatures, 293.15, 303.15, 313.15 and 323.15 K by using conductance measurements. By drawing the relation between molar conductance and ratio of metal to ligand, the figures indicate the formation of two types of complexes with M:L ratios 1:2 and 1:1 stoichiometric complexes.
- Sanad, Sameh G.,Shebl, Magdy
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- Design, synthesis and characterization of bimetallic palladium complexes for terminal olefin epoxidation
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A series of aromatic ring spaced binuclear Pd(II) complexes were synthesized from sterically tuned Schiff base ligands derived from 4,6-diacetylresorcinol and 2,6-dialkyl substituted anilines to provide a general and flexible set of complexes for terminal olefin epoxidation studies using "green" oxidant 30 % hydrogen peroxide as a terminal oxidant. All the compounds were fully characterized by analytical and spectrometric methods. Additionally, the ligands L1 and L2 were characterized by single crystal X-ray diffraction technique. The complexes C1 and C2 displayed high activity and substrate selectivity in the oxidation of 1-octene, whereas mixed products were observed in case of styrene with reasonable yields, arguably assignable to stringent steric and electronic factors of the complexes employed. Up to 98.5 % conversion is observed for epoxidation of 1-octene with high substrate selectivity, whereas up to 95 % conversion is observed for styrene with poor selectivity. Graphical Abstract: A series of Pd(II) complexes were synthesized from sterically tuned Schiff base ligands derived from 4,6-diacetylresorcinol and 2,6-dialkyl substituted anilines to provide a flexible set of complexes for olefin epoxidation studies using hydrogen peroxide as a terminal oxidant. The complexes C1-C3 showed substrate selectivity in the oxidation of 1-octene, where as mixed products were observed in case of styrene with reasonable yields.[Figure not available: see fulltext.]
- Netalkar, Sandeep P.,Revankar, Vidyanand K.,Nevrekar, Anupama A.
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- Spectroscopic and biological studies of mono- or binuclear complexes derived from thio-Schiff bases of some transition metals
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Two novel Schiff base ligands, 4,6-bis((E)-1-(2-mercaptophenylimino)ethyl) benzene-1,3-diol, H4La, and 1,2-((E)-1-(6-((E)-1-(2-mercaptophenylimino)ethyl) pyridine-2-yl)ethylideneamino)benzenthiol, H2Lb, have been synthesized by the condensation of 4,6-diacetyl resorcinol (DAR) or 2,6-diacetyl pyridine (DAP) with 2-aminobenzenthiol (ABT), in the molar ratio 1:2 [1 (DAR or DAP):2 ABT]. The structures of ligands were elucidated by elemental analysis, infrared (IR), UV-VIS as well as 1H-NMR. Reaction of the Schiff base ligands with the transition metals Co(II), Ni(II), Cu(II), Zn(II), VO(IV) and Ru(III) afforded two series of the corresponding transition metal complexes in the molar ratio 1:2 or 1:1. The ligand, H4La, behaves as tetrabasic hexadentate, which hosts the two metal ions at the centers of two SNO sites, while H2Lb acts as a compartmental dibasic pentadentate ligand forming mono- or binuclear complexes through the coordinate sites N3S2. The structures of the newly prepared complexes were characterized on the basis of the elemental analysis, spectroscopic data (IR, UV-VIS, 1H-NMR and ESR spectra along with magnetic susceptibility measurements) besides the molar conductance measurements and thermal gravimetric analyses. The bonding sites are the azomethane, sulfur atoms and phenolic oxygen for H4La or pyridine nitrogen for H2Lb. The complexes exhibit mono- or binuclear structures, distorted octahedral, tetrahedral, square planar or square pyramid structure. Synthesized compounds have also been screened for their biological activity against species of pathogenic fungi and bacteria and were found to possess appreciable fungicidal and bactericidal properties.
- Abou-Hussein, Azza A. A.
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- Spectroscopic investigations of new binuclear transition metal complexes of Schiff bases derived from 4,6-diacetylresorcinol and 3-amino-1-propanol or 1,3-diamino-propane
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The bifunctional carbonyl compound; 4,6-diacetylresorcinol (DAR) serves as precursor for the formation of different Schiff base ligands, which are either di- or tetra-basic with two symmetrical sets of either O2N or N2O tridentate chelating sites. The condensation of 4,6-diacetylresorcinol with 3-amino-1-propanol (3-AP) or 1,3-diaminopropane (DAP), yields the corresponding hexadentate Schiff base ligands, abbreviated as H4La and H2Lb, respectively. The structures of these ligands were elucidated by elemental analyses, IR, mass, 1H NMR and electronic spectra. Reaction of the Schiff base ligands with copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), iron(III), chromium(III), vanadyl(IV) and uranyl(VI) ions in 1:2 molar ratio afforded the corresponding transition metal complexes. A variety of binuclear complexes for the metal complexes were obtained with the ligands in its di- or tetra-deprotonated forms. The structures of the newly prepared complexes were identified by elemental analyses, infrared, electronic, mass, 1H NMR and ESR spectra as well as magnetic susceptibility measurements and thermal gravimetric analysis (TGA). The bonding sites are the azomethine and amino nitrogen atoms, and phenolic and alcoholic oxygen atoms. The metal complexes exhibit different geometrical arrangements such as square planar, tetrahedral, square pyramid and octahedral arrangement.
- Emara, Adel A.A.,Saleh, Akila A.,Adly, Omima M.I.
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- Spirochromone-chalcone conjugates as antitubercular agents: Synthesis, bio evaluation and molecular modeling studies
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A new series of spirochromone annulated chalcone conjugates were synthesized and evaluated for their antitubercular activity against Mycobacterium tuberculosis H37Rv strain. These compounds were subjected to molecular modeling studies using docking and chemoinformatics based approaches. The docking simulations were performed against a range of known receptors for chalcone derived compounds to reveal MTB phosphotyrosine phosphatase B [MtbPtpB] protein as the most probable target based on the high binding affinity scores. Five compounds exhibit significant inhibition, showing minimum inhibitory concentration values i.e. MIC values ranging from 3.13-12.5 μg mL-1. Further analysis of the synthesized compounds with known and in-house developed chemoinformatics tools unequivocally established their potential as anti-tubercular compounds. QSAR modeling revealed a quantitative relationship between biological activities and frontier molecular orbital energies of synthesized compounds. The predictive model can be employed further for virtual screening of new compounds in this series.
- Mujahid,Yogeeswari,Sriram,Basavanag,Díaz-Cervantes, Erik,Córdoba-Bahena, Luis,Robles, Juvencio,Gonnade,Karthikeyan,Vyas, Renu,Muthukrishnan
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p. 106448 - 106460
(2015)
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- Metal free Friedel-Crafts di-acetylation of resorcinol in acetic acid
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Conventionally, the metal catalyst used for Friedel-Crafts acetylation is poisonous and the acetylating agent is not readily available. Herein, methane sulfonic acid is developed to perform Friedel-Crafts diacetylation of aromatics instead of metal catalyst. Furthermore, acetic acid is employed as acetylating agent to replace acetic anhydride. By this approach, 4,6-diacetylresorcinol, known as an indispensable intermediate in superior fiber polybenzoxazole synthesis, is prepared in high yield from resorcinol. The results obtained by 1H NMR, FT-IR and HPLC analysis indicate that methane sulfonic acid is an efficient catalyst for Friedel-Crafts acetylation and acetic anhydride can be avoid by replacement with acetic acid, in which phosphorus pentoxide is helpful to improve conversion of desired product.
- Chen, Fenggui,Gao, Yimeng,Xu, Yuanjian
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- Design, Synthesis and In Vivo Anxiolytic Activity of Novel Flavonoids
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Worldwide millions of peoples are suffering from psychological disorders of which anxiety is one of the major and common problems. Knowing statistical reports of anxiety, the present research focused on design of new flavonoid derivatives through molecular docking by using Schr?dinger (Maestro 10.5 v), the well-known computational software on the basis of ligand – protein interaction. The most effective flavonoid derivatives with potent Glide score (IC50) values – compounds 3a (–6.824), 3b (–7.215), 3e (–6.239), 3f (-6.679), and 3j (–7.123) – were selected for the synthesis under microwave irradiation in two-step reaction involving the Claisen-Schmidth condensation to form chalcones and oxidative cyclization to form flavonoids. Then, in vivo anxiolytic activity of synthesized derivatives was studied in adult Swiss albino mice using the elevated plus-maze test model. Diazepam (2 mg/kg, IP) was used as standard drug. Compound 3b exhibited most significant anxiolytic activity against GABAA receptor, but other compounds also showed significant anxiolytic effect in mice at 100 and 200 mg/kg doses when compared to Diazepam.
- Potey, L. C.,Sabale, P. M.
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- 4,6-Diacetylresorcinol in heterocyclic synthesis Part II: Synthesis of some novel 4,6-bis(azolyl/azinyl/ azepinyl)resorcinols
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– A series of new 4,6-bis(azolyl/azinyl/azepinyl)resorcinols was synthesized in a combinatorial manner besides, (2E,2'E)-4,6-bis[3-(aminophenyl-substituted)prop-2-en-1-oxo-1-yl]resorcinols were also obtained. Heterocyclization of (2E,2'E)-4,6-bis[3-(dimethylamino)prop-2-en-1-oxo-1-yl]resorcinol (2) with nitrogen-containing binucleophiles afforded the target compounds. All the newly synthesized compounds were characterized by spectral tools.
- Assiri, Mohammed A.,Ali, Tarik E.,Ibrahim, Magdy A.,El-Amin,Yahia
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p. 114 - 125
(2019/06/24)
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- Coordination behavior of new bis(tridentate ONO, ONS and ONN) donor hydrazones towards some transition metal ions: Synthesis, spectral, thermal, antimicrobial and antitumor studies
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Three new hydrazone ligands, H2L1, H2L2 and H4L3, were prepared by condensation of 4,6-bis(1-hydrazonoethyl)benzene-1,3-diol with furan-2-carboxaldehyde, thiophene-2-carboxaldehyde and 1H-pyrrole-2-carboxaldehyde, respectively. The ligands reacted with copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II) and dioxouranium(VI) ions to yield binuclear complexes formulated as [(L)M2(OAc)2(H2O)n(EtOH)m]·xH2O·yEtOH where L = L1 or L2; M = Cu, Ni, Co, Zn or Cd; n = nil, 1 or 4; m, x and y = nil or 1, [(H2L2)Cd2(OAc)4(H2O)2]·EtOH, [(L)(UO2)2(OAc)2(H2O)2Y2]·nH2O where L = L1 or L2; Y = nil or H2O; n = 2.5 or 7, [(L3)M2(H2O)6]·nH2O where M = Cu or Zn; n = 1 or 6, [(L3)(UO2)2(H2O)4]·2.5H2O and dimeric complexes; [(L1)2Ni2]·3H2O and [(H2L3)2M2]·nH2O where M = Ni or Co; n = 1.5 or 3. The ligands and their metal complexes were characterized by elemental analyses, IR, 1H and 13C NMR, electronic, ESR and mass spectra, conductivity, magnetic susceptibility measurements and powder XRD as well as thermal analysis. The coordinating sites are phenolic oxygens, azomethine nitrogens and the hetero O/N/S atoms. Octahedral, tetrahedral and square planar geometrical arrangements are proposed for metal complexes whilst the uranium ion is hepta- or octa-coordinated. The kinetics of the thermal decomposition for some metal complexes were studied and their thermodynamic parameters were calculated using Coats-Redfern method. The antimicrobial activity of the ligands and their complexes was screened. The antitumor activity of the ligands and their complexes was tested on Ehrlich Ascites Carcinoma. Copper(II) complexes showed promising IC50 values, which are comparable to that of cisplatin.
- Shebl, Magdy
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- Efficient symmetrical bidentate dioxime ligand-accelerated homogeneous palladium-catalyzed Suzuki-Miyaura coupling reactions of aryl chlorides
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A series of N,O-bidentate ligands were synthesized using the Vilsmeier-Haack reaction and oximation. 2,5-Dihydroxyterephthalaldehyde dioxime (L8) as an efficient N,O-symmetrical bidentate ligand was prepared from hydroquinone. It was studied as a high activity ligand for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of aryl chlorides with arylboronic acids under mild conditions. The coupling reactions were performed in the presence of PdCl2 as the catalyst, L8 as the ligand, Na2CO3 as the base, PEG-400 as the PTC and in ethanol/water (1?:?1) as an environmentally benign solvent at 85 °C. Plentiful biaryls were obtained by the optimized reaction with good yields at a low palladium loading of 0.20 mol%.
- Song, Jinyi,Zhao, Hongyan,Liu, Yang,Han, Huatao,Li, Zhuofei,Chu, Wenyi,Sun, Zhizhong
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supporting information
p. 372 - 376
(2016/12/30)
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- Benzo [1,2-d:5,4-d '] b (oxazole) - 2,6-di-thiol and its preparation method
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The invention discloses benzo [1, 2-d: 5, 4-d']-di-(oxazole)-2, 6-dithiol and a preparation method thereof. The preparation method comprises the steps as follows: resorcinol is taken as a raw material, zinc chloride is taken as a catalyst, resorcinol and zinc chloride react with acetic oxide to obtain 4, 6-diacetylresorcinol; 4, 6-diacetylresorcinol reacts with hydroxylamine hydrochloride in sodium hydroxide to obtain 4, 6-di-[(1Z)-N-hydroxyethyliminumacyl]benzene-1, 3-diphenol; 4, 6-di-[(1Z)-N-hydroxyethyliminumacyl]benzene-1, 3-diphenol is taken as a raw material and subjected to Beckmann rearrangement reaction in a polyphosphoric acid system to obtain DAR*HCl; and DAR*HCl is taken as a raw material and reacts with carbon disulfide in a potassium hydroxide solution to obtain a target compound. According to the invention, sulfydryl is introduced at 2 and 6 sites simultaneously, the product is prepared through multiple steps of reaction, the method is simple, convenient and easy to operate, the melting point of the product is higher than 300 DEG C, and the yield is high.
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Paragraph 0012; 0018-0020
(2018/09/02)
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- One-pot synthesis preparation 4,6-diaminoresorcinol method of hydrochloride
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The invention discloses a method for preparing 4,6-diaminoresorcinol dihydrochloride through one-pot synthesis. The method mainly comprises the steps of: by taking Bronsted acid such as polyphosphoric acid, concentrated sulfuric acid or methanesulfonic acid as the catalyst and the solvent, realizing oximation, Beckmann rearrangement, hydrolysis and hydrocchlorination of 4,6-diacetylresorcinol, and thus obtaining the 4,6-diaminoresorcinol dihydrochloride (DAR.2HCl), wherein the mol ratio of hydroxylamine hydrochloride, the Bronsted acid catalyst and the 4,6-diacetylresorcinol is (2.0-2.5)/(1-10)/1, and the reaction temperature ranges from 65 to 125 DEG C. The method provided by the invention is simple in process steps and efficient in preparation; therefore, the industrialization of the 4,6-diaminoresorcinol dihydrochloride is greatly promoted.
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Page/Page column 13
(2016/10/08)
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- Bis-chalcones and flavones: Synthesis and antimicrobial activity
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A series of bis-chalcones (3a-g) and their flavones derivatives (4a-g) were synthesized and evaluated for their antimicrobial activity. Bis-chalcones were prepared by condensing 1,1′-(4,6-dihydroxy-1,3-phenylene) diethanone (2) with appropriate aryl aldehydes following Claisen-Schmidt reaction conditions. Oxidative cyclization of bis-chalcones (3a-g) in DMSO in the presence of iodine furnished flavones (4a-g). The synthesized compounds were evaluated for their antibacterial and antifungal actions against some selected microbes. The results of antimicrobial evaluation showed that some of the synthesized compounds were good in their antibacterial and antifungal actions.
- Husain, Asif,Rashid, Mohd.,Mishra, Ravinesh,Kumar, Deepak
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p. 443 - 449
(2013/07/28)
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- Synthesis and antimicrobial activity of bischalcone derivatives
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Several bischalcones (2a-h and 5a-e) and flavones (3a-f) were synthesized and evaluated for their antimicrobial actions. Bischalcones were prepared by condensing 1,1′-(4,6-dimethyl-1,3-phenylene)diethanone (1) or 1-(5-acetyl-2,4-dimethoxyphenyl)-1-ethanone (4) with arylaldehydes. Bischalcones were cyclized in presence of iodine to give corresponding flavones (3a-f). An alternative route to synthesize the flavones consisted in preparing the diester derivatives (6a-f) of (1) with different aromatic acids, which could be converted to β-diketones followed by cyclization to give the corresponding flavones. However, all the attempts in this direction were unsuccessful and it could not be possible to proceed beyond diester stage; six diester derivatives (6a-f) were synthesized. The structures of the synthesized compounds were assigned on the basis of 1H NMR, mass spectral data and microanalyses results. The antimicrobial screening was performed at a concentration of 100 μg/mL by cup plate method; the compounds inhibiting growth of one or more of the microorganisms were further tested for their minimum inhibitory concentration (MIC) by turbidity method. Preliminary antimicrobial results revealed that the compounds 2a-h and 3a-f were significant in their antibacterial and antifungal activities. MICs results showed that the compound 2f exhibited very good activity against E. coli, P. aeruginosa, and C. albicans with MIC-12.5 μg/mL. Similar type of activity was shown the compound 3a against S. aureus and C. albicans with MIC-12.5 μg/mL. Another compound, 3f, was active against P. aeruginosa and C. albicans with MIC-12.5 μg/mL. Methylation of the two chelated hydroxyls (5a-e) significantly reduced the activity. However, oxidative cyclization of bischalcones resulted in compounds (3a-f) which were found to be considerably active. Diesters (6a-f) were insignificant in their antimicrobial activities.
- Husain, Asif,Ahmad, Aftab,Mkhalid, Ibraheem Ahmed I.,Mishra, Ravinesh,Rashid, Mohd
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p. 1578 - 1586
(2013/07/26)
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- 4,6-diacetylresorcinol in heterocyclic synthesis, part i: Synthesis and biological evaluation of some new linearly and angularly substituted pyrano[3,2-g] chromenes via vilsmeier-haack formylation of 4,6- diacetylresorcinol, its schiff bases, and hydrazones
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Application of Vilsmeier-Haack reaction on 4,6-diacetylresorcinol (1) led to the formation of 4,6-dioxo-4H,6H-pyrano[3,2-g]chromene-3,7-dicarboxaldehyde (2) in good yield. The dicarboxaldehyde 2 was condensed with some carbon and nitrogen nucleophiles. Some aliphatic and aromatic Schiff bases of 4,6-diacetylresorcinol (1) were subjected to Vilsmeier-Haack formylation reaction to afford 4,6-bis(alkyl/arylimino)-4H,6H-pyrano[3,2-g]chromene-3,7- dicarbaldehydes 10, 14, and 15. Also, treatment of some bis-hydrazones of 4,6-diacetylresorcinol 16-19 with Vilsmeier-Haack reagent afforded the corresponding 4,6-bis(4-formylpyrazol-3-yl)resorcinols 20 and 21, which underwent oxidation with iodine to yield the pyrano[3,2-g]chromeno[4,3-c:7,6-c] dipyrazole-4,8-diones 22 and 23, respectively. Most of the synthesized compounds revealed weak antimicrobial activities. It was noticed that the dicarboxaldehydes 2, 10, 14, and 15 exhibited moderate antibacterial activity against Gram-positive bacteria, yeast, and fungus. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Ali, Tarik E.,Ibrahim, Magdy A.,El-Gendy, Zeinab M.,El-Amin, Eman M.
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p. 3329 - 3341
(2013/10/01)
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- Bis-chalcone analogues as potent NO production inhibitors and as cytotoxic agents
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Chalcones have a distinctive 1,3-diarylpropenone skeleton and exert numerous biological effects. Using a one-step Claisen-Schmidt condensation, we synthesized eleven bis-chalcones (3-13) and three acetyl chalcones (14-16) from substituted aldehydes and diacetylresorcinol. The compounds were tested for in vitro cytotoxic activity against four human cancer cell lines (A549, DU145, KB, and KB-VIN) and inhibition of NO production in lipopolysaccharide (LPS)-activated microglial cells. Among them, four compounds (3, 5, 6, and 13) showed significant cytotoxic activity with EC50 values ranging from 1.57 to 5.14 μM, and seven compounds (3, 5-8, 10, and 13) displayed potent anti-inflammatory activity by inhibiting NO production with IC50 values ranging from 0.95 to 8.65 μM. A mechanism of action study of active compounds 6 and 7 discovered that these compounds down-regulated iNOS expression by inhibiting p65 NF-κB activation/nuclear translocation due to prevention of IκBα degradation. Structure-activity relationship (SAR) findings are also discussed.
- Vijaya Bhaskar Reddy,Shen, Yuh-Chiang,Ohkoshi, Emika,Bastow, Kenneth F.,Qian, Keduo,Lee, Kuo-Hsiung,Wu, Tian-Shung
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experimental part
p. 97 - 103
(2012/03/08)
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- Synthesis, spectroscopic and biological activities studies of acyclic and macrocyclic mono and binuclear metal complexes containing a hard-soft Schiff base
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Mono- and bi-nuclear acyclic and macrocyclic complexes with hard-soft Schiff base, H2L, ligand derived from the reaction of 4,6-diacetylresorcinol and thiocabohydrazide, in the molar ratio 1:2 have been prepared. The H2L ligand reacts with Co(II), Ni(II), Cu(II), Zn(II), Mn(II) and UO2(VI) nitrates, VO(IV) sulfate and Ru(III) chloride to get acyclic binuclear complexes except for VO(IV) and Ru(III) which gave acyclic mono-nuclear complexes. Reaction of the acyclic mono-nuclear VO(IV) and Ru(III) complexes with 4,6-diacetylresorcinol afforded the corresponding macrocyclic mono-nuclear VO(IV) and Ru(IIII) complexes. Template reactions of the 4,6-diacetylresorcinol and thiocarbohydrazide with either VO(IV) or Ru(III) salts afforded the macrocyclic binuclear VO(IV) and Ru(III) complexes. The Schiff base, H2L, ligand acts as dibasic with two NSO-tridentate sites and can coordinate with two metal ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all the complexes, except in the case of the acyclic mononuclear Ru(III) and VO(IV) complexes, where the Schiff base behaves as neutral tetradentate chelate with N2S2 donor atoms. The ligands and the metal complexes were characterized by elemental analysis, IR, UV-vis 1H-NMR, thermal gravimetric analysis (TGA) and ESR, as well as the measurements of conductivity and magnetic moments at room temperature. Electronic spectra and magnetic moments of the complexes indicate the geometries of the metal centers are either tetrahedral, square planar or octahedral. Kinetic and thermodynamic parameters were calculated using Coats-Redfern equation, for the different thermal decomposition steps of the complexes. The ligands and the metal complexes were screened for their antimicrobial activity against Staphylococcus aureus as Gram-positive bacteria, and Pseudomonas fluorescens as Gram-negative bacteria in addition to Fusarium oxysporum fungus. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.
- Abou-Hussein, Azza A.A.,Linert, Wolfgang
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experimental part
p. 596 - 609
(2012/08/08)
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- A new synthesis of flavones and pyranoflavone by intramolecular photochemical Wittig reaction in water
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A new synthetic approach toward the synthesis of flavones and pyranoflavone has been developed by light induced intramolecular photochemical Wittig reaction in water onto aryloxycarbonyl groups and suitably substituted phosphonium bromides sans any phase transfer catalyst or promoter.
- Das, Jhantu,Ghosh, Somnath
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supporting information; experimental part
p. 7189 - 7194
(2012/01/05)
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- Synthesis of isoxazoline N -oxides via [hydroxy(tosyloxy)iodo]benzene (HTIB)-mediated oxidative N-O coupling
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An HTIB mediated oxidative N-O coupling strategy for the synthesis of some isoxazoline N-oxide derivatives from β-hydroxyketoximes is described, along with a comparative study of the efficiency of N-O coupling in two different solvents. A plausible mechanism for the conversion is proposed.
- Raihan, Mustafa J.,Kavala, Veerababurao,Habib, Pateliya Mujjamil,Guan, Qiao-Zhi,Kuo, Chun-Wei,Yao, Ching-Fa
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supporting information; experimental part
p. 424 - 434
(2011/04/17)
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- A facile demethylation of ortho substituted aryl methyl ethers promoted by AlCl3
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An efficient and practical demethylation of ortho substituted aryl methyl ethers using AlCl3 has been developed. This method gives a high conversion, is simple to operate and is cost-effective. A mechanism involving the complexation of AlCl3 with the OMe and the adjacent electron withdrawing group is proposed. Many functional groups can be tolerated in the demethylation process, and 29 examples gave a demethylated product in a yield of 90-98%.
- Du, Zhen-Ting,Lu, Jing,Yu, Hong-Rui,Xu, Yan,Li, An-Pai
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experimental part
p. 222 - 227
(2010/08/04)
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- Studies on the synthesis, spectra, catalytic and antibacterial activities of binuclear ruthenium(II) complexes
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A new series of stable binuclear ruthenium(II) carbonyl complexes of the general formula [{RuX(CO)(EPh3)2}2L] (where X = H or Cl; E = P or As and L = dibasic tetradentate diacetyl resorcinol (H 2-DAR)) have been synthesised by reacting ruthenium(II) starting complexes [RuHX(CO)(EPh3)3] (where X = H or Cl; E = P or As) and 4,6-diacetylresorcinol (H2-DAR) ligand in benzene medium. The structure of the new binuclear ruthenium(II) carbonyl complexes was established using elemental analysis, spectra (FT-IR, UV-vis and 1H NMR), electrochemical and thermal studies. In these reactions, the 4,6-diacetylresorcinol (H2-DAR) ligand behaves as a binegative tetradentate chelating ligand coordinating through O,O atoms of both the carbonyl and phenolic C-O groups by replacing a molecule of PPh 3/AsPh3 and a hydride ion from the starting complexes. Further, all these complexes were also employed as new catalysts for the oxidation of primary and secondary alcohols in the presence of N-methylmorpholine-N-oxide (NMO) as a more viable co-oxidant. The free ligand and their metal complexes have also been screened for their antibacterial activity against the growth of gram +ve and gram -ve bacterial cultures.
- Krishnamoorthy,Sathyadevi,Deepa,Dharmaraj
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experimental part
p. 258 - 263
(2010/09/06)
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- New 4,6-diacetyl resorcinol Mannich bases: Synthesis and biological evaluation
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In the present study, a series of Mannich bases was synthesized by condensing 4,6-diacetylresorcinol with formaldehyde and some selected secondary amines following the Mannich reaction conditions. Findings revealed that Mannich reaction did not take place at the acetyl function but occurred on the aromatic ring position between the two hydroxyl groups. It was also observed that in one case instead of the desired base (3a), the dimer (4) of the starting material (4,6-diacetylresorcinol) having a methylene bridge could be isolated. The newly synthesized compounds were characterized on the basis of elemental analysis as well as 1H NMR and mass spectral data. The products have been evaluated for antiinflammatory, ulcerogenic and lipid peroxidation actions with some significant results.
- Khan, Mohammed Sardaryar,Husain, Asif,Sharma, Sanjay
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scheme or table
p. 261 - 266
(2011/07/09)
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- Synthesis and microbiological evaluation of mannich bases derived from 4,6-diacetylresorcinol
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In the present investigations 4,6-diacetyl resorcinol 1 on condensation with formaldehyde and some selected amines following the Mannich reaction conditions yielded eight new Mannich bases 2a-h. It was observed that the reaction did not take place at the acetyl function but occurred at the 2-position into the aromatic ring. The compounds were characterized on the basis of elemental analysis as well as 1H NMR and Mass spectral data. The antibacterial and antifungal activities of the title compounds were tested by the disc diffusion method using nutrient agar medium against various microorganisms such as gram positive Staphylococcus aureus and Bacillus subtilis, gram negative Escherichia coli and the fungi Aspergillus flavus and Candida albicans. Ofloxacin and voriconazole at 20 μg/mL were used as standard drugs for antibacterial and antifungal activities, respectively.
- Husain, Asif,Maaz, Mohammad,Ansari, Khursheed Ahmad,Ahmad, Ausaf,Rashid, Mohd.
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experimental part
p. 332 - 334
(2011/10/02)
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- Synthesis of 2.8-dicyclohexyl-4h, 6h-benzo [1,2-b: 5,4-b′] dipyran-4,6-diones under phase transfer catalysis conditions and their antimicrobial activity
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An efficient route for the synthesis of 2,8-dicyclohexyl-4H, 6H-benzo [1,2-b: 5,4-b′] dipyran-4,6-diones (2a-f) under phase transfer catalysis conditions (PTC) has been developed by the base catalyzed reaction of substituted resorcinols (1a-f) with cyclohexanoyl chloride in good yields.
- Rajyalakshmi,Shravani,Rajaiah,Rao, A. V. Subha,Ashok
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experimental part
p. 381 - 384
(2012/01/04)
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- Synthesis and spectroscopic studies of binuclear metal complexes of a tetradentate N2O2 Schiff base ligand derived from 4,6-diacetylresorcinol and benzylamine
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A tetradentate N2O2 donor Schiff base ligand, H2L, was synthesized by the condensation of 4,6-diacetylresorcinol with benzylamine. The structure of the ligand was elucidated by elemental analyses, IR, 1H NMR, electronic and mass spectra. Reaction of the Schiff base ligand with nickel(II), cobalt(II), iron(III), cerium(III), vanadyl(IV) and uranyl(VI) ions in 1:2 molar ratio afforded binuclear metal complexes. Also, reaction of the ligand with several copper(II) salts, including Cl-, NO3-, AcO-, ClO4- and SO42- afforded different metal complexes that reflect the non-coordinating or weakly coordinating power of the ClO4- anion as compared to the strongly coordinating power of SO42- and Cl- anions. Characterization and structure elucidation of the prepared complexes were achieved by elemental and thermal analyses, IR, 1H NMR, electronic, mass and ESR spectra as well as magnetic susceptibility measurements. The metal complexes exhibited different geometrical arrangements such as square planar, octahedral, square pyramidal and pentagonal bipyramidal arrangements. The variety in the geometrical arrangements depends on the nature of both the anion and the metal ion.
- Shebl, Magdy
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experimental part
p. 850 - 859
(2009/02/01)
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- Spectroscopic studies of bimetallic complexes derived from tridentate or tetradentate Schiff bases of some di- and tri-valent transition metals
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Two series of new binuclear complexes with Schiff base ligands, H4La or H2Lb, derived from the reaction of 4,6-diacetylresorcinol and ethylenediamine, in the molar ratio 1:1 and 1:2 have been prepared, respectively. The two ligands react with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Cr(III) and Fe(III)-nitrates to get binuclear complexes. The ligands were characterized by elemental analysis, IR, UV-vis, 1H NMR and mass spectra. The complexes were synthesized by direct and template methods. Different types of products were obtained for the same ligand and metal salts according to the method of preparation. The H4La ligand behaves as a macrocyclic tetrabasic with two N2O2 sits, while the H2Lb ligand behaves as a dibasic with two N2O sites. The H4La ligand is a compartmental ligand which hosts the two metal ions at the centers of two cis-N2O2 sites, while the metal complexes of H2Lb ligand are binuclear, where the ligand hosts two metal ions at the centers of two N2O sites. In both cases, deprotonation of the hydrogen atoms of the phenolic OH groups occur except in the case of the Ni(II), Fe(III) and Cr(III) complexes. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either octahedral or tetrahedral. The structures are consistent with the IR, UV-vis, ESR, 1H NMR, mass spectra, and thermal gravimetric analysis (TGA/DTA) as well as conductivity and magnetic moment measurements.
- Emara, Adel A.A.,Abou-Hussen, Azza A.A.
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p. 1010 - 1024
(2007/10/03)
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- PROCESS FOR THE PREPARATION OF A COSMETIC ACTIVE
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A process for the preparation of formula (1): wherein R is alkyl or aryl, cyclic or acyclic, substituted or unsubstituted, and optionally containing one or more oxygen, nitrogen or sulphur heteroatoms; comprising reacting resorcinol with an alkanoic carboxylic acid in the presence of a Lewis acid or a Bronsted acid catalyst, wherein the mole ratio of the acid catalyst to resorcinol is at least one and the mole ratio of alkanoic acid to resorcinol is at least two.
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- Process for producing 4,6-diaminoresorcinols
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A process for producing 4,6-diaminoresorcinols comprises the steps of: subjecting a dioxime of the formula (4) STR1 wherein R is an alkyl or phenyl group, to Beckmann rearrangement to thereby produce 4,6-diacylaminoresorcinol of the formula (5) STR2 wherein R is as defined above, and subjecting the 4,6-diacylaminoresorcinol to hydrolysis and recovering the product 4,6-diaminoresorcinol (6) STR3 or a salt thereof.
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- A novel and facile synthesis of tetraacylbenzenes
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1,3-Dibenzoyl-2,4-diacyl- and 1,5-Dibenzoyl-2,4-diacylbenzene are prepared in good yields via a further application of a recently reported two step replacement of phenolic hydroxyl by an acyl group.
- Kotali, Antigoni
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p. 6753 - 6754
(2007/10/02)
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- Leukotriene B4 Receptor Antagonists: The LY255283 Series of Hydroxyacetophenones
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A series of hydroxyacetophenones was prepared for evaluation as leukotriene B4 (LTB4) receptor antagonists, culminating in 1-oxy>phenyl>ethanone (compound 35, LY255283).Using an assay for inhibition of specific LTB4 binding to human PMN, we found that substitution of a nonpolar substituent in the 5-position was required for activity.Best activity was realized with hydrogen in the 3-position, hydroxyl in the 2-position, short chain alkyl ketone in the 1-position, and a six- or eight-carbon chain linking the oxygen in the 4-position with an unsaturated terminal function.Compound 35, having an IC50 of 87 nM in the binding assay, was chosen for further preclinical evaluation.
- Herron, David K.,Goodson, Theodore,Bollinger, Nancy G.,Swanson-Bean, Dorothy,Wright, Ian G.,et al.
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p. 1818 - 1828
(2007/10/02)
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- Claisen Rearrangement of Prenyl Ethers of Isomeric Acetylnaphthols and Bisprenyl Ethers of 4,6- and 2,4-Diacetylresorcinols
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Claisen rearrangements of the 3-methylbut-2-enyl(prenyl)ethers 3 and 9 of 2-acetyl-1-hydroxy- and 1-acetyl-2-hydroxynaphthalenes 1 and 2 and the bis(3-methylbut-2-enyl)ethers 12 and 18 of 2,4- and 4,6-diacetylresorcinols 11 and 17 have been studied under a variety of thermal and catalytic conditions. 2-Acetyl-4-(3-methylbut-2-enyl)naphthalene-1-ol 4 was the sole product on rearrangement of compound 3, in DMA or neat.Under catalytic conditions 3,4-dihydro-2,2-dimethyl-2H-naphthopyran 7 was obtained in poor yield.An isomeric pyran, 1,2-dihydro-3,3-dimethyl-3H-naphthopyran 10 (25-43percent) was obtained under both thermal and catalytic conditions from 9.The rearrangement of 12 under thermal conditions (DMA and neat) furnished 3-acetyl-2,4-dihydroxy-5-(3-methylbut-2-enyl)acetophenone 13 and 3,8-diisopropylbenzodifuran 14.Pd'' mediated rearrangement of 12 gave only the partially deprenylated ether, 3-acetyl-4-hydroxy-2-(3-methylbut-2-enyloxy)acetophenone 15 (29percent).While the isomeric ether 18 gave the monoprenyl ether, 5-acetyl-4-hydroxy-2-(3-methylbut-2-enyloxy)acetophenone 19 in quantitative yield (95percent).The rearrangment products were characterised and their formation rationalised in terms of allowed sigmatropic shifts( prenyl and H) followed by loss of prenyl or acetyl groups.The reactions of prenyl ethers are both comparable to those of the corresponding allyl ethers and consistent with the greater fixed double-bond character of the naphthalene system compared to that of benzene.Prenyl derivatives of benzene and naphthalene containing ortho - hydroxyacetophenone units were formed which have potential in synthesis.
- Anjaneyulu, Ammanamanchi S. R.,Isaa, Balagopala M.
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p. 2089 - 2094
(2007/10/02)
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- ANTI-INFLAMMATORY AGENTS
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This invention provides benzene derivatives, pharmaceutical formulations of those derivatives, and a method of using the derivatives for the treatment of inflammation in mammals.
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- Thermal Claisen Rearrangement Studies on 4,6- and 2,4-Diacetylresorcinol Bisallyl Ethers: Observation of Loss or Sigmatropic Shift of Acetyl Groups
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Thermal Claisen rearrangement of 4,6-diacetylresorcinol bisallyl ether (2) in N,N-dimethylaniline gave a mixture of readily characterised products.While no rearrangement occurred with lower boiling solvents (benzene and dioxane), higher boiling solvents (diphenyl ether and glycerol) gave rise to more complex rearrangement and a lowering of the yields of isolable products.Trifluoroacetic acid both at room temperature and 60 deg C effected either partial or total deallylation but no rearrangement.Product formation has been rationalised in terms of symmetry allowed sigmatropic allyl, acetyl or H shifts followed by allyl or acetyl group loss; the latter is a novel obsrevation.The acetyl group, most probably eliminated as a cation, effected both O-acylation and nuclear acylation of the substrates.Claisen rearrangement of the bromo and nitro derivatives of compound (2) in which the ortho and para positions are blocked, gave products arising from bromo and nitro group elimination.Rearrangement of 2,4-diavetylresorcinol bisallyl ether N,N-dimethylaniline occurred similarly.
- Anjaneyulu, Ammanamanchi S. R.,Mallavadhani, Uppuluri V.
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p. 623 - 628
(2007/10/02)
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- Benzodipyrazoles: Non-Xanthine Adenosine Antagonists
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3,5-Dimethylbenzodipyrazoles, optionally substituted in the 1-, 7-, and 8-positions, were synthesized from resorcinols.These compounds display affinity for adenosine A1 (rat brain) and A2 (human platelet) receptors.In addition, these compounds reverse contractions of guinea pig tracheal cylindrical segments induced by potassium chloride, histamine, acetylcholine, and 5-hydroxytryptamine, as well as reverse bronchospasm induced by aerosolized histamine in the conscious guinea pig.
- Peet, Norton P.,Dickerson, George A.,Abdallah, Abdulminium H.,Daly, John W.,Ukena, Dieter
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p. 2034 - 2039
(2007/10/02)
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- Reaction of Acetic Anhydride/Zinc Chloride Reagent with Phenols: Improved Yields of Hydroxyacetophenones
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Acetic anhydride/zinc chloride has been found to be a better acylating system for phenol and polyphenols resulting in improved yields of the respective hydroxyacetophenones.The phenols used are phenol, resorcinol, hydroquinonone, catechol, phloroglucinol and pyrogallol.With resorcinol the isomeric diacetyl derivatives are formed in excellent yields in a single step, while catechol and hydroquinone give only monoacetyl derivatives like simple phenol.Pyrogallol gives a monoacetyl derivative while phloroglucinol gives both mono and diacetyl derivatives but not triacetyl derivatives.
- Anjaneyulu, A. S. R.,Mallavadhani, U. V.,Venkateswarlu, Y.,Prasad, A. V. Rama
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p. 823 - 826
(2007/10/02)
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- Thermal Claisen Rearrangement of Bisprenyl Ether of 2,6-Diacetylresorcinol
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The thermal Claisen rearrangement of the bisprenyl ether (2) of 4,6-diacetylresorcinol (1) has been studied by refluxing in different solvents like N,N-dimethylaniline, o-xylene and n-decane and also by heating it neat in a sealed tube at 155 deg C and 185 deg C. 5,7-Diacetyl-2,3-dihydro-4-hydroxy-2,3,3-trimethylbenzofuran (3) is found to be the major product along with 3-acetyl-2,4-dihydroxy-5-(3,3-dimethylallyl)acetophenone (4) and 5-acetyl-2,4-dihydroxy-3-(3,3-dimethylallyl)acetophenone (5).The products have been characterised by their spectral data (IR, UV, PMS and mass) and their formation has been rationalised.
- Anjaneyulu, A. S. R.,Isaa, B. Meher,Mallavadhani, U. V.
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p. 1140 - 1142
(2007/10/02)
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- A Convenient Method for the Preparation of 2,4-Dihydroxy-5-acetylacetophenone
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2,4-Dihydroxy-5-acetylacetophenone (resodiacetophenone) is obtained in good yield by heating resorcinol with anhydrous ferric chloride and acetyl chloride.This method is found to be more convenient and superior than the other literature methods.
- Balasubramanian, A.,Sankaran, P.
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