Room Temperature Catalytic Aromatization of Hantzsch 1,4-Dihydropyridines by Sodium Nitrite in the Presence of Acidic Silica Gel

2006 ◽  
Vol 137 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Mohammed M. Hashemi ◽  
Hossein Ghafuri ◽  
Zahed Karimi-Jaberi
Keyword(s):  
Silica Gel ◽  
Sodium Nitrite ◽  
Room Temperature ◽  
Catalytic Aromatization

Synthesis and aldol cyclotrimerization of 4,7-di-tert-butylacenaphthenone

2006 ◽  
Vol 84 (10) ◽  
pp. 1268-1272 ◽  
Author(s):  
Aaron W Amick ◽  
Keith S Griswold ◽  
Lawrence T Scott
Keyword(s):  
Key Words ◽  
Crystal Structures ◽  
Silica Gel ◽  
Room Temperature ◽  
Titanium Tetrachloride ◽  
X Ray ◽  
Synthetic Intermediates

An efficient gram scale synthesis of the previously unknown 4,7-di-tert-butylacenaphthenone (3b) is reported. The facile isomerization of epoxide 9b to ketone 3b occurs simply on stirring a solution of 9b with silica gel at room temperature. Aldol cyclotrimerization of 3b with titanium tetrachloride gives 2,5,8,11,14,17-hexa-tert-butylde cacyclene (1b) in 58% isolated yield. X-ray crystal structures have been obtained for the synthetic intermediates 4,7-di-tert-butylacenaphthene (2b) and 4,7-di-tert-butylacenaphthylene (8b).Key words: aromatic, decacyclene, hydrocarbon, nonalternant, polycyclic.

scholarly journals Comparison of preservation methods of Atta spp. (Hymenoptera: Formicidae) for RAPD analysis

2000 ◽  
Vol 29 (3) ◽  
pp. 489-496 ◽  
Author(s):  
Alfredo O. R. Carvalho ◽  
Luiz G. E. Vieira
Keyword(s):  
Silica Gel ◽  
Low Temperatures ◽  
Room Temperature ◽  
Rapd Analysis ◽  
Limiting Factors ◽  
Dna Yield ◽  
Remote Locations ◽  
Leaf Cutting ◽  
Storage Methods ◽  
Plot Design

High quality DNA for molecular studies can be easily extracted from fresh specimens. However, live samples are difficult to keep for long periods thus making their preservation a serious problem, specially when they are collected and transported from remote locations. In order to establish an efficient method to preserve Atta spp. (leaf-cutting ants) for RAPD analysis, six different storage methods were examined: 1) -70°C; 2) 95% ethanol at -20°C; 3) 95% ethanol at 4°C; 4) 95% ethanol at room temperature; 5) silica gel at room temperature; and 6) buffer (0.25 M EDTA, 2.5% SDS, 0.5 M Tris-HCl, pH 9.2) at room temperature. DNA was extracted (Cheung et al., 1993 - modified) and examined after 90, 210 and 360 days of storage. Freshly killed specimens were used as control. DNA yield was measured with a minifluorometer. DNA quality was determined by scanning photographs with a densitometer and the integral of the scan was calculated for DNA of size > 9.4 kb. Data were analyzed using a completely randomized split-plot design with four replicates. All methods were efficient to preserve Atta spp. DNA up to 210 days. At 360 days, DNA was degraded only in 95% ethanol at room temperature, which resulted in RAPD profiles with missing bands. Although preservation at low temperatures is recommended for long periods, methods using silica gel and buffer can be considered satisfactory alternatives when refrigeration and transportation are limiting factors.

An Efficient Two-Step Protocol for the Isoprenylation of Xanthone at the C2 Position Starting from 1-Fluoroxanthone Derivative

Synlett ◽  
2020 ◽  
Vol 31 (14) ◽  
pp. 1423-1429
Author(s):  
Takashi Matsumoto ◽  
Yuuki Fujimoto ◽  
Chisato Furukawa ◽  
Kanae Takahashi ◽  
Miho Mochizuki ◽  
...  
Keyword(s):  
Silica Gel ◽  
Room Temperature ◽  
Claisen Rearrangement ◽  
High Yield ◽  
Side Chain ◽  
Snar Reaction

The SNAr reaction of 1-fluoroxanthone derivatives with alkoxide of 1,1-dimethylallyl alcohol cleanly afforded the corresponding ethers, which have thus far been unavailable. The obtained ethers underwent the Claisen rearrangement at room temperature by treatment with silica gel in toluene. This two-step protocol provides expeditious and high-yield access to xanthones possessing isoprenyl or the related allylic side chain at the C2 position.

scholarly journals An Alternative Process for Leaching Chalcopyrite Concentrate in Nitrate-Acid-Seawater Media with Oxidant Recovery

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 518 ◽  
Author(s):  
César I. Castellón ◽  
Pía C. Hernández ◽  
Lilian Velásquez-Yévenes ◽  
María E. Taboada
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Alkaline Solution ◽  
Sodium Nitrite ◽  
Sodium Nitrate ◽  
Room Temperature ◽  
Leaching Test ◽  
Copper Concentrate ◽  
Leaching Process ◽  
Chalcopyrite Concentrate

An alternative copper concentrate leaching process using sodium nitrate and sulfuric acid diluted in seawater followed by gas scrubbing to recover the sodium nitrate has been evaluated. The work involved leaching test carried out under various condition by varying temperature, leaching time, particle size, and concentrations of NaNO3 and H2SO4. The amount of copper extracted from the chalcopyrite concentrate leached with seawater, 0.5 M of H2SO4 and 0.5 M of NaNO3 increased from 78% at room temperature to 91% at 45 °C in 96 h and 46 h of leaching, respectively. Gas scrubbing with the alkaline solution of NaOH was explored to recover part of the sodium nitrate. The dissolved salts were recovered by evaporation as sodium nitrate and sodium nitrite crystals.

scholarly journals Determination of Diethanolamine in Shampoo Products Containing Fatty Acid Diethanolamides by Liquid Chromatography with a Thermal Energy Analyzer

2005 ◽  
Vol 88 (2) ◽  
pp. 592-594 ◽  
Author(s):  
Hardy J Chou
Keyword(s):  
Acetic Acid ◽  
Liquid Chromatography ◽  
Fatty Acid ◽  
Thermal Energy ◽  
Sodium Nitrite ◽  
Room Temperature ◽  
Energy Analyzer

Abstract A liquid chromatography (LC) method using a thermal energy analyzer (TEA) is described for the determination of diethanolamine (DEA) in shampoo products containing fatty acid diethanolamides. DEA was converted to N-nitrosodiethanolamine (NDELA) by dissolving a portion of the product in 6M acetic acid and mixing with sodium nitrite for 1 h at room temperature. The reaction mixture was dried, dissolved in acetone, and analyzed for NDELA by LC-TEA. The recovery of DEA from 2 shampoo products at fortification levels of 25, 250, and 1000 ppm ranged from 70 to 105%. Twenty shampoo products were analyzed by this method, and 19 were found to contain DEA at levels ranging from 140 to 15 200 ppm.

scholarly journals ISOLATION AND PHYTOCHEMICAL TEST OF ANTICANCER ISOLATE OF SPONGE Hyrtios erecta

2017 ◽  
Vol 1 (1) ◽  
pp. 16
Author(s):  
I Made Dira Swantara ◽  
Wiwik Susanah Rita ◽  
Rr Anisa Hernindy
Keyword(s):  
Stationary Phase ◽  
Anticancer Activity ◽  
Silica Gel ◽  
Screening Test ◽  
Mobile Phase ◽  
Room Temperature ◽  
Ethanol Extract ◽  
Toxicity Screening ◽  
Polyphenol Compounds ◽  
Thousand Islands

AbstractThis research aims to isolate and phytochemically test of the toxic isolate from ethanol extract of the sponge Hyrtios erecta taken from the waters of Pari Island beach, Thousand Islands (Jakarta). Extraction of the sponges was carried out by 70% ethanol at room temperature. Partition and purification of the compounds were done by column chromatography with the stationary phase of silica gel and the mobile phase of n-hexane-chloroform (2:8). Toxicity screening test was done based on Bhrine Shrimp Lethality Test (BSLT). The compounds of the active isolate were performed by phytochemical test. Based on the results, it was found that the toxic isolate of Hyrtios erecta sponges has anticancer activity with IC50 of 30,497 ppm. The anticancer isolate contained alkaloid, steroid, and polyphenol compounds

scholarly journals Silica: An efficient catalyst for one-pot regioselective synthesis of dithioethers

2014 ◽  
Vol 10 ◽  
pp. 26-33 ◽  
Author(s):  
Samir Kundu ◽  
Babli Roy ◽  
Basudeb Basu
Keyword(s):  
Silica Gel ◽  
Room Temperature ◽  
Allyl Bromide ◽  
Solvent Free ◽  
Regioselective Synthesis ◽  
Selective Synthesis ◽  
Tandem Reactions ◽  
One Pot ◽  
Efficient Catalyst

The development of a silica-promoted highly selective synthesis of 1,2 or 1,3-dithioethers via solvent-free one-pot tandem reactions of an allyl bromide with excess thiol at room temperature is described. The choice of silica gel, either pre-calcined or moistened with water, exhibited notable regioselectivity in the formation of dithioethers. Plausible mechanistic routes were explored and postulated.

ChemInform Abstract: Birch Reductions at Room Temperature with Alkali Metals in Silica Gel (Na2K-SG(I)).

ChemInform ◽  
2009 ◽  
Vol 40 (52) ◽  
Author(s):  
Partha Nandi ◽  
James L. Dye ◽  
James E. Jackson
Keyword(s):  
Silica Gel ◽  
Alkali Metals ◽  
Room Temperature

scholarly journals The reaction between aluminium metal and aqueous solutions of the nitrite ion

1980 ◽  
Vol 33 (1) ◽  
pp. 169 ◽  
Author(s):  
PJ Hyde ◽  
IM Ritchie
Keyword(s):  
Aqueous Solutions ◽  
Induction Period ◽  
Sodium Nitrite ◽  
Room Temperature ◽  
Nitrite Ion ◽  
Aluminium Metal ◽  
Mechanism Of The Reaction

The reaction between aluminium metal and a 0.1 wt % solution of sodium nitrite at room temperature is described. Initially the reaction is slow, but after an induction period the aluminium corrodes catastrophically. The products of the reaction were identified as ammonia, hydrogen and bayerite. A possible mechanism of the reaction is suggested.

Brillouin scattering in sodium nitrite at room temperature

1972 ◽  
Vol 11 (1) ◽  
pp. 255-261 ◽  
Author(s):  
G. Hauret ◽  
J. P. Chapelle ◽  
L. Taurel
Keyword(s):  
Sodium Nitrite ◽  
Room Temperature ◽  
Brillouin Scattering
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