Manabendra Patra

Acid Hydrazides, Potent Reagents for Synthesis of Oxygen-, Nitrogen-, and/or Sulfur-Containing Heterocyclic Rings

Nitrogen‐, and/or Sulfur-Containing Heterocyclic Rings Poulomi Majumdar,†,‡ Anita Pati,†,§ Manabendra Patra, Rajani Kanta Behera,† and Ajaya Kumar Behera*,† †Organic Synthesis Laboratory, School of Chemistry, Sambalpur University, Jyoti Vihar, Burla 768019, Orissa, India ‡State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024, P.R. China School of Applied Sciences (Chemistry), KIIT University, Bhubaneswar 751024, India National Institute of Science & Technology, Palur Hill, Berhampur 761068, Orissa, India

Studies on Spiroheterocycles, Part II: Heterocyclization of the Spiro Compounds Containing Cyclohexanone and Thiobarbituric Acid with Different Bidentate Nucleophilic Reagents

Abstract The reaction of thiobarbituric acid with different diarylidene ketones 1a–c yields the spiro compounds 2a–c. The diarylidene derivatives 3a–c are synthesized by the condensation of spiro compounds 2a–c with different aldehydes. A series of spiro heterocycles compounds 4a–l, 5a–l, 6a–l, 7a–l, 8a–l, and 9a–l are synthesized from the diarylidene compounds. The structures of the compounds are ascertained from their analytical and spectral data. Some of the compounds are screened for their biological activities.

Acrylamide polymerization initiated with the redox system Ce(IV)-cyclohexanone in micellar phase: A kinetic study

The effect of an organized anionic surfactant, i.e. sodium dodecyl sulfate (SDS), on the acrylamide (AM) polymerization initiated with the redox system Ce(IV)-cyclohexanone (CH) in aqueous nitric acid was kinetically studied over a temperature range of 25 -45 °C. With increasingconcentration of SDS, above its critical micelle concentration (CMC) the rate of polymerization, R p(obs) , as well as the rate of Ce(IV) consumption, -R Ce(obs) , were found to increase, while in the presence of cetyltrimethylammonium bromide (CTAB ) these rates decreased considerably. R p(obs) is proportional to [Ce(IV)] 0.5 , [CH] 0.5 and [AM] 1.5 ,-R Ce(obs) also increases with increasing concentration of Ce(IV), cyclohexanone and acrylamide. The overall activation energy for the process, in the presence and absence of 15 x 10 -3 M of SDS, was calculated to be 15.1 and 21.4 kcal/mol, respectively. The viscosity average molecular weight of polyacrylamide was found to increase with increasing SDS concentration. A suitable mechanistic scheme for the polymerization process is proposed.

Studies on Spiroheterocycles, Part III: Synthesis of Diazaspiroundecanetetraone Derivatives Containing Biologically Active Heterocycles

Barbituric acid 2 upon Michael addition with dibenzal acetones 1a–c afforded the corresponding diazaspiro derivatives 3a–c . The base-catalyzed condensation of 3a–c with various aromatic aldehydes produces diarylidine derivatives 4a–l . The diarylidene compounds 4a–l on condensation with hydrazine, phenyl hydrazine, hydroxylamine, urea, guanidine carbonate, and hydrazine hydrate with acetic acid afforded their respective in situ oxidized products 5, 6, 7, 8, 9 , and 10 . The structures of the compounds are ascertained from their analytical and spectral data. Some of the compounds are screened for their biological activities against E. coli, B. cirroflagellosus, A. niger, and C. albicans.

POLYMERIZATION OF ACRYLAMIDE INITIATED BY KMnO4-CYCLOHEXANONE REDOX SYSTEM IN PRESENCE OF SURFACTANT

The polymerization kinetics of acrylamide (AM) using KMnO4-Cyclohexanone (CH) redox system as an initiator in the presence of surfactant was studied over a temperature range of 30–50°C in acidic medium. The anionic surfactant, sodium dodecyl sulphate (SDS) above its CMC enhances the rate of polymerization (Rp ) as well as the rate of MnO4 − disappearance (−RMn ). However, the presence of a cationic surfactant (CTAB) in the reaction medium, decreases both Rp and −RMn , while a non-ionic surfactant (TX-100) has no effect on the rate. The effects of changes in the concentration of surfactant, monomer, MnO4 −, cyclohexanone, and acid on the rate of polymerization were also examined. The overall activation energy values were found to be 23.45 and 19.89 Kcal/mole in the absence and in the presence of 0.015M SDS in the reaction medium respectively. The viscosity average molecular weight (Mv) of the obtained polymer has also increased with the concentration of SDS. A suitable mechanistic scheme for the polymerization kinetics involving free radicals has been proposed for the process and rate expressions are derived.

Effect of organized anionic surfactant system on the kinetics of V(V)-organic substrate-initiated polymerization of acrylonitrile

The kinetics of polymerization of acrylonitrile (AN) initiated by a V(V)-cyclohexanone redox system in the presence ofa surfactant was studied over a temperature range of 30-50°C in acidic medium. The anionic surfactant sodium dodecyl sulfate (SDS) enhances the rate of polymerization (R p ) as well as rate of V(V) consumption (-R υ ). The cationic surfactant, cetyltrimethylammonium bromide (CTAB), decreases both R p and -R υ , while the nonionic surfactant, Triton-X-100, has no effect on the rate. The change of concentration of the surfactant, monomer, acid, and cosolvent on the rate of polymerization were examined. Both R π and -R υ are computed in the presence of different organic substrates, i.e., cyclohexanone, cyclopentanone, glycerol, and citric acid. The viscosity-average molecular weight (M υ ) of the polycrylonitrile, obtained at different [SDS], was determined using the Mark-Howink relationship. A suitable mechanistic scheme was proposed for the process.

Polymerization of methyl acrylate initiated by V(V)-cyclohexanone redox system in micellar phase

The kinetics of methyl acrylate (MA) polymerization initiated by a V(V)-Cyclohexanone redox system, in the presence of surfactant, over a temperature range of 30–50°C in acidic medium are analyzed. The anionic surfactant (SDS) enhances the rate of polymerization (Rp) as well as the rate of V(V) consumption (−Rv). The cationic surfactant, cetyl trimethylammonium bromide (CTAB), decreases both the rates. The effect of variation of the concentration of surfactant, monomer, substrate, and acid have been examined. A suitable free radical mechanistic scheme has been proposed for the above process.

Effect of organized anionic surfactant system on kinetics of polymerization of acrylonitrile initiated by Ce(IV) : Citric acid and other organic substrates

The polymerization of acrylonitrile (AN) using the Ce(IV)-citric acid (CA) redox system as an initiator in aqueous nitric acid solution, in the presence of an anionic surfactant, sodium dodecyl sulfate (SDS), has been kinetically studied at a temperature range of 25-45°C. The rate of polymerization (R p ) and disappearance of Ce(IV) (-R Ce ) increase with increasing concentration of SDS, above its critical micelle concentration (cmc), when the surfactant molecules are organized. R p was found to be proportional to [AN] 1.5 and [CA] 0.5 . With other organic substrates, R p follows the increasing order of sorbitol ≥ mannitol > glycerol > CA. But it was found to decrease considerably in the presence of cationic surfactant (CTAB), and nonionic surfactant (Triton-X-100) had no effect on the rate. -R Ce varies linearly with [Ce(IV)] and [CA]. Both R p and -R Ce increase with increasing temperature. The overall activation energy was found to be 18.31 and 13.72 kcal/mol in the absence and presence of 0.015M SDS, respectively. The chain length of the polyacrylonitrile has also increased with increasing SDS concentration

Synthesis and spectral properties of macrocyclic compounds containing 1,3,4-thiadiazole moeties connected by a carbon-oxygen bridge

Abstract The syntheses of 1∶1‐macrocycles 3 (n=1), unsymmetrical macrocycle 5 (m=0, n=1), 2∶2‐macrocycle 5 (m=n=1 and 2), 3∶3 macrocycle 7, and several open‐chain ethereal compounds prepared from 2,5‐dichloro‐1,3,4‐thiadiazole 1 and various polyethylene glycols dianions are described. Structural proofs are afforded by their mass and NMR spectral features. The quaternization studies of a few macrocycles with methyl iodide at elevated temperature furnished a diketo derivative 8 through a facile Hilbert–Johnson reaction.

Polymerization of acrylamide initiated by V(V)-cyclohexanone redox system in micellar phase : A kinetic study

The kinetics of acrylamide (AM) polymerization initiated by V(V)-cyclohexanone(CH) redox system in the presence of anionic surfactant, sodium dodecyl sulphate (SDS), in aqueous sulphuric acid have been studied over a temperature range of 30-50°C. The rate of Polymerization, RP(obs), as well as the rate of V(V) consumption, -RV, were found to increase in the presence of SDS, above its CMC, while decrease with cationic surfactant, cetyl trimethylammonium bromide (CTAB). The non-ionic surfactant, TX-100, has no effects on the rates. Both the rates were also determined at varying concentration of AM, V(V), CH, H+ and at various ionic strength in the presence of 0.015M SDS in the solution. The overall activation energy for the proccesses calculated from the Arrhenious plot, were found to be 19.34 and 26.58 kcal/mol in the presence and absence of 0.015M SDS. The viscosity average molecular weight of the polymer obtained in presence of SDS increases with the concentration of SDS. A suitable free radical mechanis...