Dielectric Relaxation Studies of Binary Mixtures of N,N-Dimethylformamide and N,N-Dimethylacetamide in Benzene Solutions Using Microwave Absorption Technique

Sharma, Anshu; Sharma, D. R.

doi:10.1143/jpsj.53.4471

Cited by 11 publications

(13 citation statements)

References 9 publications

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“…This natural medicine is prescribed in the form of direct mixtures with powders or extracts of other natural medicines for use as anti-obesity, antiinflammatory, antibacterial, anticoagulant, and anti-atherosclerosis agents in Ayurvedic folk medicine in India. Previously, the antiinflammatory activity of guggul has been reported, [1][2][3] and guggulsterone, a constituent of guggul, activates lipolytic enzymes, inhibits hepatic cholesterol biosynthesis, and reduces the total serum lipid and total serum cholesterol levels. 4,5) A similar natural medicine, myrrh [the resin of Balsamodendron (or Commiphora) myrrha NEES] was used by the Egyptians for embalming, and by the Jews as an anointing oil.…”

mentioning

confidence: 99%

Absolute Stereostructures of Polypodane-Type Triterpenes, Myrrhanol A and Myrrhanone A, from Guggul-Gum Resin (the Resin of Balsamodendron mukul)

Matsuda

Morikawa

Ando

et al. 2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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Guggul-gum resin [the resin of Balsamodendron (ϭCom-miphora) mukul HOOK. (Burseraceae)] is produced by drying the milky-white sap of the tree (15-20 years old) for one year. This natural medicine is prescribed in the form of direct mixtures with powders or extracts of other natural medicines for use as anti-obesity, antiinflammatory, antibacterial, anticoagulant, and anti-atherosclerosis agents in Ayurvedic folk medicine in India. Previously, the antiinflammatory activity of guggul has been reported, [1][2][3] and guggulsterone, a constituent of guggul, activates lipolytic enzymes, inhibits hepatic cholesterol biosynthesis, and reduces the total serum lipid and total serum cholesterol levels. 4,5) A similar natural medicine, myrrh [the resin of Balsamodendron (or Commiphora) myrrha NEES] was used by the Egyptians for embalming, and by the Jews as an anointing oil. The sesquiterpene constituents isolated from myrrh, furanoeudesma-1,3-diene and curzarene, have analgesic effects that are blocked by naloxone, explaining the use of myrrh as a painkiller in ancient times. 6) However, because of its toxicity, myrrh is not used in medicines today, except as a mouthwash in India.In the course of our characterization studies on traditional Ayurvedic medicines, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] we found that the 50% aqueous methanolic extract of guggul (the resin of B. mukul) showed an anti-inflammatory effect on adjuvant-induced air pouch granuloma in mice. From the extract, two new polypodanetype triterpenes, myrrhanol A (1) and myrrhanone A (2), were isolated as the active components. 7) Furthermore, the methanolic extract of this natural medicine was found to exhibit an inhibitory effect on nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages. From the methanolic extract, we isolated three polypodanetype triterpenes named myrrhanol B (3), myrrhanones B (4), and A acetate, and an octanordammarane-type triterpene termed epimansumbinol, together with 17 known constituents.8) This paper presents a full account of the isolation and characterization of myrrhanol A (1) and myrrhanone A (2).The 50% aqueous methanolic extract (5.68% from natural medicine) of the resin of guggul-gum was partitioned in an ethyl acetate (EtOAc) and water mixture to furnish the EtOAc-and H 2 O-soluble fractions. The EtOAc-soluble fraction was subjected to normal and reversed phase silica gel column chromatographies, and finally HPLC, to give two new polypodane-type triterpenes, myrrhanol A 7) (1, 0.036%) and myrrhanone A 7) (2, 0.026%), together with four polypodane-type triterpenes, myrrhanol (Table 1) spectra of 1, which were assigned by various NMR experiments, 27) showed a presence of seven tertiary methyls [d 0.75, 0.79, 0.98, 1.13, 1.65 (s, 24, 25, 23, 26, 29-H 3 ), 1.60 (s, 27, 28-H 3 )], a methine bearing an oxygen function [d 3.21 (dd, Jϭ4.9, 11.6 Hz,], a methylene bearing an oxygen function [d 3.96 (s, 30-H 2 )], and three trisubstituted olefins [d 5.12 (dd, Jϭ...

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mentioning

confidence: 99%

Absolute Stereostructures of Polypodane-Type Triterpenes, Myrrhanol A and Myrrhanone A, from Guggul-Gum Resin (the Resin of Balsamodendron mukul)

Matsuda

Morikawa

Ando

et al. 2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…ÁH " , ÁF " and ÁS " are the enthalpy, free energy and entropy of activation, respectively for dielectric relaxation process, and ÁH , ÁF and ÁS are corresponding parameters for the viscous flow. The plot of log(T ) versus 10 3 /T (figure 1) and log() versus 10 3 /T according to equations (10) and (12) were found to be linear, which shows that both relaxation and viscous processes can be considered as rate processes. The ÁH " and ÁH values were computed from the slope of the linear plot of log(T ) versus 10 3 /T and log() versus 10 3 /T, respectively using the relation: slope ¼ ÁH/2.303R.…”

Section: Resultsmentioning

confidence: 89%

“…This has motivated the authors to undertake experimental work concerning dielectric relaxation process in the binary mixture of NMA and NMF, in order to throw light on the molecular association in the whole concentration range of NMF in the binary mixtures. Dielectric relaxation studies of liquid mixtures in the microwave region have been recognized to characterize different types of molecular interactions such as solute-solute, solute-solvent and self-association in the solution [9][10][11]. In order to obtain some information about the behavior of NMA þ NMF mixtures in the microwave region, dielectric relaxation measurements of the dilute solution of binary mixtures of these solvents in benzene have been performed at 9.90 GHz frequency of the microwave region.…”

Section: Introductionmentioning

confidence: 99%

Dielectric relaxation studies of binary mixtures ofN-methylacetamide andN-methylformamide in benzene solutions using microwave absorption data

Kumar

Rangra

Sharma

et al. 2007

Physics and Chemistry of Liquids

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Using standard microwave X-band technique and by following Gopala Krishna's single frequency (9.90 GHz) concentration variational method, the dielectric relaxation times () and the dipole moments () of dilute solution of N-methylacetamide (NMA), N-methylformamide (NMF) and NMA þ NMF binary mixtures in benzene solutions have been calculated at different temperatures. The energy parameters for the dielectric relaxation process for NMA þ NMF binary mixture containing 30 mol% NMF have been calculated at 25, 30, 35 and 40 C and compared with the corresponding viscosity parameters. A good agreement between the free energy of activation from these two sets of values shows that the dielectric relaxation process like the viscous flow process can be treated as the rate process. From relaxation time behavior of NMA and NMF binary mixture in benzene solution, solute-solute types of the molecular association has been proposed.

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“…1),2) SiC whiskers have been grown by several processes including the carbothermal reduction of silica, 3) reactions between silicon halides and CCl 4 , 4) and chemical vapor deposition (CVD) using a metallic catalyst such as Ni or Fe. 5) Another technique is the growth of SiC whiskers through a CVD vaporsolid mechanism using no catalysts.…”

Section: Introductionmentioning

confidence: 99%

Fabricating SiC whiskers of different sizes by controlling only the CVD deposition position

Choi

Kim

Park

et al. 2010

J. Ceram. Soc. Japan

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Silicon carbide (SiC) whiskers were produced at different positions in the chemical vapor deposition (CVD) furnace. The effect of shifts in specimen position on vaporsolid (VS) whisker growth was studied. First, we confirmed the major factors influencing CVD whisker growth by controlling the specimen position. The source reactant depletion effect and temperature gradient acted to reduce the whisker diameter by 33.3 and 61.7%, but the gas residence time only accounted for 4.2% of whisker diameter reduction. The specimen upon which all three factors acted showed a 74.2% decrease in diameter. Transmission electron microscopy (TEM) observation showed that all whiskers had highly crystalline FCC structures. The front perpendicular specimen showed higher stacking fault densities, whereas the back horizontal specimen possessed no stacking faults. These results suggest that position variation led to a growth rate difference, which affected the stability of whisker growth. Based on this idea, we confirmed the possibility of synthesizing whiskers of two different diameters on the same substrate. This can propose a new network structure consisting of combined whiskers. This report focuses on varying the whisker deposition size by controlling the deposition position instead of changing the deposition conditions as is common.

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Dielectric Relaxation Studies of Binary Mixtures of N,N-Dimethylformamide and N,N-Dimethylacetamide in Benzene Solutions Using Microwave Absorption Technique

Cited by 11 publications

References 9 publications

Absolute Stereostructures of Polypodane-Type Triterpenes, Myrrhanol A and Myrrhanone A, from Guggul-Gum Resin (the Resin of Balsamodendron mukul)

Absolute Stereostructures of Polypodane-Type Triterpenes, Myrrhanol A and Myrrhanone A, from Guggul-Gum Resin (the Resin of Balsamodendron mukul)

Dielectric relaxation studies of binary mixtures ofN-methylacetamide andN-methylformamide in benzene solutions using microwave absorption data

Fabricating SiC whiskers of different sizes by controlling only the CVD deposition position

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