7539-23-3Relevant articles and documents
Lewis acid–catalyzed green synthesis and biological studies of pyrrolo[3,4-c]pyrazoles in aqueous medium
Arjuna, Anania,Kaur, Manpreet,Singh, Baldev
, (2019/12/24)
An environmentally benign approach in aqueous medium by means of Lewis acid catalyst affords a wide spectrum of pyrazoline derivatives in satisfactory yields. [3+2] cycloaddition reactions of substituted azomethine-N-imines to maleimide in aqueous medium at relatively high concentrations of Lewis acid catalyst have emerged as an environment friendly alternative to conventional solvents. Promising catalytic activity has been revealed by Lewis acid like Cu (NO3)2 in aqueous medium. The obvious features of this synthetic protocol were short reaction time, high efficiency, less hazardous synthesis by benign solvent, catalysis, modest workup, and a clean reaction methodology.
Facile synthesis of pyrazoles by iron-catalyzed regioselective cyclization of hydrazone and 1,2-diol under ligand-free conditions
Panda, Niranjan,Ojha, Subhadra
, p. 244 - 251 (2018/03/13)
A facile synthesis of pyrazoles by the cyclization of hydrazones and 1,2-diols was described. In the presence of ferric nitrate, the reaction occurs under neat conditions and makes the use of potassium persulfate to oxidize the diol to α-hydroxy carbaldehyde for the reaction with hydrazones to produce 1,3- and 1,3,5-substituted pyrazoles selectively. The overall regioselective transformation occurs in one-pot under ligand-free, mild conditions even in the presence of air.
Fe+3-montmorillonite K10 as an Efficient Reusable Heterogeneous Catalyst for the Grind Mediated Synthesis of 14-aryl-14H-dibenzo [a,j]xanthenes
Fekri, Leila Z.,Nikpassand, Mohammad,Fard, Hajar S.,Marvi, Omid
, p. 135 - 142 (2016/03/01)
Background: Xanthenes are an important class of organic compounds and have also received significant attention due to their wide range of pharmacological activities such as antibacterial, antiviral, antiinflammatory activities, antagonists for the paralyzing action of zoxazolamine and efficiency in photodynamic therapy, a well-known method for controlling the localized tumors. Natural sources are also rich of xanthene compounds. Popularly known pigments, santalin have been isolated from plant species. Furthermore, these compounds can be emerged as pH-sensitive fluorescent materials for visualization of biomolecules, in laser technologies and as dyes. There are several reports in the literature for the synthesis of xanthenes such as alkylations of heteroatoms, cyclodehydrations, cyclocondensations between 2-hydroxyaromatic aldehydes and 2- tetralone, trapping of benzynes by phenols and intramolecular phenyl-carbonyl coupling reactions of benzaldehydes and acetophenones bearing tethered carbonyl chains in the presence of hexamethylphosphoramide and SmI2. Other methods for the synthesis of xanthenes include the reaction of formamide with β-naphthol, carbon monoxide, and 1- hydroxymethyl-naphthalen-2-ol. Methods: procedure a: A mixture of substituted benzaldehyde, 2-naphtol and Fe+3-montmorillonite K10 was mixed. After completion of the reaction, the product was solved in CHCl3 (3×10 mL) and insoluble catalyst was removed by filtration. The organic phase including the product and chloroform was evaporated under vacuum. The resulting crude material was purified by recrystallization from EtOH to afford pure products. procedure b: A mixture of substituted benzaldehyde, phenylhydrazine and Fe+3-montmorillonite K10 were added to a mortar and the mixture was pulverized with a pestle. After completion of the reaction, 2-naphtol was added to the consulting mixture and pulverized with a pestle. The organic phase including the product and chloroform was evaporated under vacuum. The resulting crude material was purified by recrystallization from EtOH to afford pure products. Results: As part of our going interest for the development of efficient and environmentally friendly procedures for the synthesis of heterocyclic and pharmaceutical compounds, we wish to report the first grind mediated synthesis of some derivatives of xanthenes using catalytic amount of Fe+3-montmotillonite. Conclusion: In conclusion, we have investigated the Fe+3-montmorillonite K10 under grinding as a mild and efficient catalyst for the synthesis of substituted 14-aryl-14H-dibenzo [a,j]xanthenes. The remarkable advantages offered by this method are: catalyst is inexpensive, non-toxic, easy handling and reusability, simple work-up procedure, short reaction time, high yields of product with better purity and green aspect by avoiding toxic catalyst and hazardous solvent.
Nano BF3·SiO2: A green heterogeneous solid acid for synthesis of formazan dyes under solvent-free condition
Bamoniri, Abdolhamid,Mirjalili, Bi Bi Fatemeh,Moshtael-Arani, Naimeh
, p. 272 - 278 (2014/07/22)
A solvent-free, efficient and rapid approach for synthesis of formazan dyes was developed by diazotization of aromatic amines with NaNO2, nano silica-supported boron trifluoride (nano BF3·SiO2), then diazo coupling with aldehyde phenylhydrazones by grinding method at room temperature. This study aimed to overcome the limitations and drawbacks of the previous reported methods such as: low temperature, using corrosive and toxic acids and solvents, using buffer solutions, instability of aryl diazonium salts, modest yields, and long reaction times.
One-pot tandem synthesis of tetrasubstituted pyrazoles via 1,3-dipolar cycloaddition between aryl hydrazones and ethyl but-2-ynoate
Ningaiah, Srikantamurthy,Doddaramappa, Shridevi D.,Chandra,Madegowda, Mahendra,Keshavamurthy, Shubakara,Bhadraiah, Umesha K.
supporting information, p. 2222 - 2231 (2014/07/07)
1,3,4,5-Tetrasubstituted pyrazoles are rapidly and regioselectively synthesized in a one-pot, three-step sequence consisting of condensation, nitrilimine generation, and cycloaddition using mercuric acetate. Newly synthesized compounds were characterized by spectral studies. Regiochemistry of compounds 6a and 8a was determined as 1,4- and 1,5-regioisomers respectively by X-ray crystallography. Copyright
Fast hydrazone reactants: Electronic and acid/base effects strongly influence rate at biological pH
Kool, Eric T.,Park, Do-Hyoung,Crisalli, Pete
supporting information, p. 17663 - 17666 (2014/01/06)
Kinetics studies with structurally varied aldehydes and ketones in aqueous buffer at pH 7.4 reveal that carbonyl compounds with neighboring acid/base groups form hydrazones at accelerated rates. Similarly, tests of a hydrazine with a neighboring carboxylic acid group show that it also reacts at an accelerated rate. Rate constants for the fastest carbonyl/hydrazine combinations are 2-20 M-1 s-1, which is faster than recent strain-promoted cycloaddition reactions.
1, 3-Dipolar cycloaddition reactions: Synthesis of 5-benzyl-1-(2',4'- dibromophenyl)-3-(4''-substituted phenyl)-3a,4,6,6a-tetrahydro-1H, 5H-pyrrolo[3,4-c]pyrazole-4,6-dione derivatives
Kaur, Manpreet,Singh, Baldev,Singh, Baljit
, p. 1529 - 1534 (2014/04/03)
1,3-Dipolar cycloaddition of nitrilimines 3 with N-benzyl maleimide 4 has provided 5-benzyl-1-(2',4'-dibromophenyl)-3-(4''-substituted phenyl)-3a,4,6,6a-tetrahydro-1H,5H-pyrrolo[3,4-c]pyrazole-4,6-dione derivatives 5 in excellent yield as the only isomer through a concerted pathway. Indian Academy of Sciences.
A novel synthesis of 1,3,5-trisubstituted pyrazoles through a spiro-pyrazoline intermediate via a tandem 1,3-dipolar cycloaddition/elimination
Dadiboyena, Sureshbabu,Valente, Edward J.,Hamme II, Ashton T.
supporting information; experimental part, p. 291 - 294 (2009/04/14)
The syntheses of an important class of hitherto unreported 1,3,5-pyrazoles, inspired by an unanticipated eliminatory ring opening are described. The reported pyrazole compounds were constructed through the Huisgen cyclization of 2-methylene-1,3,3-trimethy
Synthesis, spectroscopic and electrochemical studies on bis-[1,3-substituted (Cl, Br) phenyl-5-phenyl formazanato]nickel(II) complexes
Tezcan, Habibe,Uzluk, Elif,Aksu, M. Levent
experimental part, p. 973 - 982 (2009/02/03)
In this study, new 1:2 Ni complexes of 1,3-substituted phenyl-5-phenylformazans were synthesized with -Cl, -Br substituents in the o-, m-, p-positions of the 1-phenyl ring and -NO2 group in the m-position of the 3-phenyl ring. Their structures were elucidated and spectral behaviors were investigated with the use of elemental analysis, GC-Mass, 1H NMR, 13C NMR, FTIR, UV-vis spectra. Furthermore electrochemical properties such as number of electrons transferred (n), diffusion coefficients (D) and possible reaction mechanism of the compounds were determined with the use of cyclic voltammetry, ultramicrodisc electrode and chronoamperometry. The relation between their absorption properties and electrochemical properties was examined. A linear correlation was obtained between Hammett substituent coefficients with λmax values.
In situ alcohol oxidation-protection reactions
Kiasat,Kazemi,Nourbakhsh
, p. 1555 - 1558 (2007/10/03)
The one-pot conversion of primary and secondary alcohols into phenylhydrazones and 2,4-dintrophenylhydrazones is reported using chromium trioxide supported on silica gel and phenylhydrazines or 2,4- dintrophenylhydrazines under solvent-free conditions. This oxidation arylhydrazone formation reaction has been applied to a range of aliphatic and benzylic alcohols. Copyright Taylor & Francis, Inc.
