Influence of ammonium chloride on growth and fatty acid production by spirulina platensis

Changes in growth and fatty acid content ofSpirulina platensis were examined after transferring cells into media containing various concentrations of ammonium chloride. Photosynthetic O₂ evolution rate decreased with increasing ammonium chloride concentration. Therefore, the algal growth was interrupted by ammonium chloride addition. On the other hand, total fatty acid content markedly increased after addition of ammonium chloride to a concentration of 15–50 mM and was maximized 40–48 h after addition of 25 mM ammonium chloride. The increases in palmitic and oleic acid content were especially remarkable. However, this began to decrease 48 h after the addition of 25 mM of ammonium chloride. Also, γ-linolenic acid content increased continuously during a 72-h incubation. As a result,Spirulina platensis cells containing about 2% γ-linolenic acid were obtained by ammonium chloride treatment, representing an increase of 1.5–2-fold compared to untreated cells.     

Phase transformations of ammonium tungsten bronzes

This article discusses the formation and structure of ammonium tungsten bronzes, (NH₄) _x WO_3−y . As analytical tools, TG/DTA-MS, XRD, SEM, Raman, XPS, and ¹H-MAS NMR were used. The well-known α-hexagonal ammonium tungsten bronze (α-HATB, ICDD 42-0452) was thermally reduced and around 550 °C a hexagonal ammonium tungsten bronze formed, whose structure was similar to α-HATB, but the hexagonal channels were almost completely empty; thus, this phase was called reduced hexagonal (h-) WO₃. In contrast with earlier considerations, it was found that the oxidation state of W atoms influenced at least as much the cell parameters of α-HATB and h-WO₃, as the packing of the hexagonal channels. Between 600 and 650 °C reduced h-WO₃ transformed into another ammonium tungsten bronze, whose structure was disputed in the literature. It was found that the structure of this phase—called β-HATB, (NH₄)_0.001WO_2.79—was hexagonal.     

Regioselective Heterocyclization of 3-(Cyclohex-2′-enyl)-4-hydroxy-6-methylpyran-2-one

Summary.  Regioselective heterocyclization of 3-(cyclohex-2′-enyl)-4-hydroxy-6-methyl pyran-2-one with various reagents afforded different heterocycles. With N-iodosuccinimide in acetonitrile at 0–5°C it gave 6-methyl-9′-iodo-2′-oxabicyclo[3.3.1]nonano[3,2-c]pyran-2-one, with C₅H₅NHBr₃ or C₆H₁₂N₄HBr₃ in CHCl₃ at 0–5°C it furnished 6-methyl-9′-bromo-2′-oxabicyclo[3.3.1]nonano[3,2-c]pyran-2-one. Cold concentrated H₂SO₄ lead to 6-methyl-2′-oxabicyclo[3.3.1]nonano[3,2-c]pyran-2-one, whereas PdCl₂(PhCN)₂ in C₆H₆ at 80°C afforded 9-methyl benzofuro[3,2-c]pyran-2-one. Corresponding author. E-mail: kcm@klyuniv.ernet.in Received December 27, 2001. Accepted (revised) March 1, 2002     

9α-hydroxylation of 25-fluoroponasterone a diacetonide in lithium-ammonia solution

25-Fluoroponasterone A diacetonide reacted with lithium in liquid ammonia to give 25-fluoro-9α,20-dihydroxyecdysone diacetonide whose hydrolysis afforded 25-fluoro-9α,20-dihydroxyecdysone 20,22-acetonide. Nonfluorinated analog of the latter was isolated previously from Silene italica ssp. nemoralis.     

Evidence for hydrophobic attraction between latex particles in aqueous systems as investigated by turbidimetry

We report the evidence for attractive interaction of latex particles which are covered by poly(ethylene oxide) chains. These particles are suspended in aqueous solutions of ammonium sulfate. The interaction is probed by measurements of the turbidity of the suspensions up to 70 g/l. Turbidity is insensitive to multiple scattering and allows the static structure factor, S(q) [q=(4πn ₀/λ₀)sin(θ/2), where θ is the scattering angle, n₀ is the refractive index of the medium and λ₀ is the wavelength in vacuo], to be determined at small q values. The analysis of S(q) at small q values yields information about possible attraction of the particles. The analysis of the turbidity data furthermore shows that no aggregation took place in these systems. A weak but long-range attractive interaction was found at ammonium sulfate concentrations of 0.01 and 0.1 M. The relation of this attractive force to hydrophobic forces is discussed. Received: 9 March 2000/Accepted: 28 June 2000     

Synthesis of perfluoroalkyl-containing tri-and tetradentate β-amino enones

Reactions of perfluoroalkyl-containing aliphatic 1,3-diketones with triethyl orthoformate afforded a number of β-ethoxy enones. Their reactions with o-phenylenediamine gave novel perfluoroalkyl-containing tridentate β-amino enones and tetradentate bis(β-amino enones) in high yields. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2086–2092, September, 2005.     

Three-component condensation of <Emphasis Type="Italic">o-</Emphasis> and <Emphasis Type="Italic">p</Emphasis>-methoxytoluenes with isobutyraldehyde and α-substituted benzyl cyanides. Synthetic approach to analogs of natural alkaloids

Three-component condensation of o(p)-methoxytoluene with isobutyraldehyde and α-substiituted benzyl cyanides gave 8-acetyl-3,6,6-trimethyl-5,6,7,12b-tetrahydrodibenzo[d,f]indol-2(1H)-one or 8-acetyl- 1,6,6-trimethyl-3,4,5,6,7,12b-hexahydrodibenzo[d,f]indol-3-one. Analogous reaction of p-methoxytoluene with isobutyraldehyde and 1-phenylcyclopentane-1-carbonitrile afforded 1’,6^’,6^’-trimethyl-3^’,4^’,5^’,6^’,7^’,12b^’-hexahy- drospiro[cyclopentane-1’,8-dibenzo[d,f]indol]-3^’-ones.     

Use of the tert-amino effect in the synthesis of spirocyclic fused α-carbolines

The use of the tert-amino effect in cyclization of reaction products from 2-(azepan-1-yl)-1-methyl-1H-indole-3-carbaldehyde and active methylene compounds afforded spirocyclic fused α-carbolines. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 371–373, February, 2006.     

Synthesis and structures of complexes ofN-2-nitroxyethylpicolinamide and 2-(2-pyridyl)-2-oxazoline with PdCl2

The reaction ofN,N′-bis(2-nitroxyethyl)pyridine-2,6-dicarboxamide with PdCl₂ afforded previously unknowncis-(N-2-nitroxyethylpicolinamide-N,N′)dichloropalladium(II) andcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(II), which were isolated as a cocrystallizate of the molecular compounds. Its structure was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1604–1606, August, 1999.     

[(1S)-endo]-(−)-borneol-tethered oxazoline phosphite as a P,N-bidentate ligand in palladium-catalyzed enantioselective allylic amination

P,N-Bidentate oxazoline phosphite containing an acyclic phosphorus center with [(1S)-endo]-(−)-borneol fragments and its palladium chelate complex [Pd(η-C₃H₅)(η²-P,N)]BF₄ were synthesized for the first time. The use of this new ligand in Pd-catalyzed asymmetric amination of 1,3-diphenylpropenyl acetate with pyrrolidine afforded the product with 86% ee. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2106–2108, December, 2006.     

Effect of cationic gemini surfactants on the hydrolysis of carboxylate and phosphate esters using hydroxamate ions

The kinetics of the hydrolysis of p-nitrophenyl acetate (PNPA) and p-nitrophenyl diphenyl phosphate (PNPDPP) by hydroxamate ions mediated by gemini surfactants with quaternary ammonium bromide (16-n-16,2Br⁻, n = 3, 4, 6, 12) and pyridinium chloride (12py-n-py12,2Cl⁻, n = 3, 4) head group have been investigated at 27 °C. The gemini surfactant with the pyridinium head group, 12-py-4-py12,2Cl⁻ (tetramethylene-1,4 bis dodecylpyridinium chloride) shows a large rate acceleration effect than that with an ammonium head group, 16-12-16,2Br⁻, relative to those in water. The apparent pK _a of the hydroxamic acids have been determined in the presence of gemini surfactants. Catalytic system N-phenylbenzohydroxamate/12py-4-py12,2Cl⁻ demonstrated over ~1,590-fold and ~255-fold rate enhancement in the hydrolysis of PNPA and PNPDPP, respectively, for the identical reaction performed in buffer aqueous media at 27 °C. The second order rate constant and binding constants for reactions were determined employing pseudophase model for micellar catalysis.     

Design of postmetallocene catalytic systems of aryliminetype for olefins polymerization: XIII. Synthesis of tetradentate bis(2-hydroxy-1-naphthaldimine) ligands and their complexes with titanium(IV) dichloride

Reactions of 2-hydroxy-1-naphthaldehyde with 1,4-diaminobutane, 1,6-diaminohexane, 4,4′-methylenedianiline and its alkyl- and cycloalkyl-sybstituted derivatives, with 4,4′-sulfonyldianiline, 2,2′- and 4,4′-oxydianiline, 4,4′-(1,4-phenylenebisoxy)dianiline, 4,4′-[propane-2,2-diylbis(1,4-phenylenebisoxy)]dianiline, and p-terphenyl-4,4″-diamine afforded a series of the corresponding diimines that at treating with TiCl₂(OPr-i)₂ formed mono- and binuclear complexes of titanium(IV) dichloride with tetradentate ligands LTiCl₂ and L₂(TiCl₂)₂.     

Regioselective bromination of quinopimaric acid derivatives

Regioselective bromination of 14β-hydroxydihydroquinopimaric acid methyl ester in acetic acid and methanol gave the corresponding 16S-bromo-, 19R-bromo-, and 16S,19R-dibromo-14β,20-epoxy derivatives whose structure was determined by X-ray analysis and NMR spectroscopy. The reactions of 16S-bromo ketones with thiourea afforded 2,1,3-thiadiazoles fused to diterpene fragment.     

Fabaceae Polysaccharides. III. Galactomannan from <Emphasis Type="Italic">Astragalus cicer</Emphasis> seeds

Seeds of Astragalus cicer L. (Fabaceae) afforded a galactomannan (5.90% yield of seed mass) of molecular weight 1064 kDa, solutions of which had high viscosity [η] 925.5 mL/g and optical activity [α]_D +71.9°. The galactomannan consisted of galactose and mannose units in a 1:1.39 ratio. Physicochemical methods established that the main chain of the polysaccharide consisted of 1,4-β-D-mannopyranose units substituted at 72% of the C-6 positions by single α-D-galactopyranose units. The content of variously substituted galactose mannobiose units Man–Man, (Gal)Man–Man/Man–Man(Gal) and (Gal)Man–Man(Gal) in the galactomannan were 18.7, 19.8, and 61.5%, respectively.     

Reaction of thiosemicarbazide with n-cyanoguanidine: synthesis of 3,5-diamino-1-thiocarbamoyl-and 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles

The reaction of thiosemicarbazide with N-cyanoguanidine in an acidic medium afforded 3,5-diamino-1-thiocarbamoyl-1,2,4-triazole, whose condensation with α-halo ketones gave 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles 7a–d. The latter were also prepared by the independent synthesis from 2-hydrazinothiazoles and N-cyanoguanidine. Acylation of compounds 7a,d under mild conditions and their condensation with aldehydes occur at the C(3′)NH₂group. The structure of aroyl derivative 11c was established by X-ray diffraction. Acylation of diaminothiazolyltriazole 7a in boiling Ac₂O afforded 3,5-diacetylamino-1-(4-phenylthiazol-2-yl)-1,2,4-triazole. Hydrogenation of arylidene derivatives 14b,c and aroyl derivative 11c gave the corresponding benzylaminotriazoles 15a,b. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 329–334, February, 2006.     

Synthesis of two new chloro derivatives of the guaianolide grossmisin and the crystal structure of one derivative

The reaction of grossmisin (8α-hydroxyachillin,1) with chlorine in benzene afforded a mixture of products. The less polar product readily crystallized after chromatography. According to the X-ray diffraction data, this product has the structure of 1α,10β-dichloro-1,10-dihydrogrossmisin. The second chloro derivative of grossmisin,viz., 8β-chloroachillin, was prepared in good yield by the reaction of lactone1 with PCl₅ in CHCl₃ in the presence of Py. Published inIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 11, pp. 1932–1934, November, 2000.     

<Emphasis Type="Italic">N</Emphasis>-alkylation of amidothiophosphoryl compounds under phase-transfer catalysis conditions. Synthesis and properties of 1,3,2-thiazaphosphacyclanes

N (ω-Haloalkyl)amidothiophosphates, N (ω-Haloalkyl)amidothiophosphonates, and N- (ω-Haloalkyl)amidothiophosphinates (Hal = Cl or Br) were obtained in high yields by alkylation of phosphorus(V) acid thioamides with 6h,ω-dihaloalkanes under phase-transfer catalysis (PTC) conditions or through the use of NaH as a base. Thermal rearrangement of N (3-iodopropyl)-or N (4-iodobutyl)amidothiophosphate and N (3-iodopropyl)-or N (4-iodo-butyl)amidothiophosphonate obtained in situ by the Finkelstein reaction provides a convenient route to 2-oxo-1,3,2-thiazaphosphinanes and 2-oxo-1,3,2-thiazaphosphepanes. Reactions of N (ω-Haloalkyl)amidothiophosphinates with NaClO₄ in MeCN afforded the first example of stable 1,3,2-thiazaphosphacyclanium salts containing P—C bonds.     

Dinitramide and its salts

N,N-Dinitro derivatives of alkylurethanes, benzamide, andp-toluenesulfamide were synthesized for the first time. Their reactions with ammonia afforded the ammonium salt of dinitramide in 44–85% yields.For part 9, seeIzv. Akad. Nauk. Ser. Khim., 1996, 451 [Russ-Chem. Bull., 199645, 433 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 908–912, April, 1996.     

Reaction of 2,2,3,3-Tetracyanocyclopropanecarboxylic Acid with Iodides. Synthesis of 3-Cyano-4-dicyanomethylidene-5-oxo-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrrol-2-olates

Reactions of 2,2,3,3-tetracyanocyclopropanecarboxylic acid with potassium, sodium, calcium, strontium, barium, ammonium, N-methylpyridinium, N-methylquinolinium, N,N-dimethyl-1,4-diazabicyclo-[2.2.2]octane-1,4-diium, and N,N-dimethylanilinium iodides afforded the corresponding 3-cyano-4-dicyanomethylidene-5-oxo-4,5-dihydro-1H-pyrrol-2-olates.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 535–538.Original Russian Text Copyright © 2005 by Kayukova, Kayukov, Nikolaev, Tafeenko, Ershov, Nasakin.     

Development and validation of an HPLC-UV detection assay for the determination of rufinamide in human plasma and saliva

The development of a simple and rapid high-performance liquid chromatography (HPLC) method for the determination of the new antiepileptic drug rufinamide (RFN) in human plasma and saliva is reported. Samples (250 μl) are alkalinized with ammonium hydroxide (pH 9.25) and extracted with dichloromethane using metoclopramide as internal standard. Separation is achieved with a Spherisorb silica column (250 × 4.6 mm i.d., 5 μm) at 30 °C using as mobile phase a solution of methanol/dichloromethane/n-hexane 10/25/65 (vol/vol/vol) mixed with 6 ml ammonium hydroxide. The instrument used was a Shimadzu LC-10Av chromatograph and flow rate was 1.5 ml min^-1, with a LaChrom L-7400 UV detector set at 230 nm. Calibration curves are linear [r ² = 0.998 ± 0.002 for plasma (n = 10) and r ² = 0.999 ± 0.001 for saliva (n = 9)] over the range of 0.25–20.0 μg ml^-1, with a limit of quantification at 0.25 μg ml^-1. Precision and accuracy are within current acceptability standards. The assay is suitable for pharmacokinetic studies in humans and for therapeutic drug monitoring.