Acetals and ethers,XVII. One- or two-step syntheses of 2-(2-alkoxyethyl)-1,3-dioxacyclanes

2-(2-Alkoxyethyl)-1,3-dioxanes (1) were prepared by ap-toluenesulfonic acid-catalyzed, one-step reaction of propenal with a mixture of aliphatic alcohol and trimethylene glycol in good yields. The transacetalization reaction of 1,1,3-trialkoxypropanes (3) with ethylene glycol or propylene-(1,2)glycol afforded good yields of pure 2-(2-alkoxyethyl)-1,3-dioxolanes (5 or6), respectively. This reaction proceeds through an intermediate 1,3-dialkoxy-1-(2-hydroxyalkoxy)-propane.

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Ein- oder Zweistufensynthese von 2-(2-Alkoxyethyl)-1,3-dioxacyclanen

Zusammenfassung In der durchp-Toluolsulfonsäure — katalysierten, direkten Reaktion von Propenal mit einem Gemisch von aliphatischem Alkohol und Trimethylenglykol wurden die entsprechenden 2-(2-Alkoxyethyl)-1,3-dioxane (1) in guten Ausbeuten erhalten. Die Umacetalisierung von 1,1,3-Trialkoxypropanen (3) mit Ethylenglykol oder 1,2-Propylenglykol lieferte 2-(2-Alkoxyethyl)-1,3-dioxolane (5 oder6) in guten Ausbeuten. Die Umacetalisierungsreaktion von 1,1,3-Trialkoxypropanen verläuft über 1,3-Dialkoxy-1-(2-hydroxyalkoxy)-propane als Zwischenprodukte.

     

Synthesis of 6-mono- and 5,6-disubstituted 1,2,3-triazolo[4,5-d]pyrimidin-7-ones

The reactions of N-substituted 4-amino-3-benzyl-1,2,3-triazole-5-carboxamides with phosphorus oxochloride and dimethylformamide at 80 °C or with triethyl orthoacetate and acetic anhydride at 160 °C afforded 6-mono- or 5,6-disubstituted 1,2,3-triazolo[4.5-d]pyrimidin-7-ones in 30—85% and 65—90% yields, respectively.     

New (1R,4R)-2-arylidene-p-menthan-3-ones with a bridging ester group in the arylidene fragment. Synthesis and behavior in liquid-crystalline systems

(1R,4R)-2-(4-Hydroxybenzylidene)- and (1R,4R)-2-(4"-hydroxybiphenyl-4-yl)methylene-p-menthan-3-ones were synthesized by condensation of (–)-menthone with O-tetrahydropyran-2-yl derivatives of 4-hydroxybenzaldehyde and 4"-hydroxy-4-formylbiphenyl, respectively, in a DMSO—base medium followed by the removal of the protective group. The reactions of these hydroxy derivatives with 4-alkylbenzoic, 4-alkyloxybenzoic, trans-4-alkylcyclohexane-4-carboxylic, and 4"-alkylbiphenyl-4-carboxylic acids afforded three series of new chiral esters. Compounds containing the arylidene moiety with three benzene rings were found to exhibit liquid-crystalline properties. The characteristic features of these compounds are discussed based on the results of studies by polarizing microscopy, differential scanning calorimetry, and small-angle X-ray scattering. It was found that the mesomorphic compounds under study can form a smectic A mesophase, twist grain boundary mesophases (TGBA), and blue phases in a wide temperature range. Upon dissolution of certain of chiral compounds in 4"-cyano-4-pentylbiphenyl, a rather high twisting power and the thermal stabilizing effect on mesophases were observed.     

Reaction of vinyloxyalkylamines with mercaptoacetic acid

N-[2(3)-Hydroxyalkylj-4-thiazolidinones have been synthesized by the reaction of 2(3)-vinyloxyalkylamines with mercaptoacetic acid in 24–69 % yield. The structure of the compounds obtained was supported by (R and¹H NMR spectroscopic data.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 677–679, March, 1996.     

Enzymatic dissymmetrization of meso-2,3-dimethylbutane-1,4-diol and its diacetate. Synthesis of scalemic (–)-lasiol

Acylation of meso-2,3-dimethylbutane-1,4-diol with vinyl acetate in the presence of porcine pancreatic lipase (PPL) leads to the dextrorotatory monoacetate of the above diol with enatiomeric excess (ee) 58—64%. Absolute configuration of this scalemic specimen was determined by its sequential transformation to levorotatory lasiol, a metabolite of the Lasius ants. Partial hydrolysis of the corresponding meso-diacetate, mediated by PPL or by the Pseudomonas sp. lipase affords the monoacetate of opposite configuration with ee 72—86%, a formal intermediate in the synthesis of (3S,4R)-faranal. Other microbial lipases used are distinctive in low chemoselectivity.     

The influence of methanol and ethanol on the efficiency of extraction of lanthanides(III) with 1-(2-pyridylazo)-2-naphthol (PAN) in carbon tetrachloride

The efficiency of extraction of microquantities of Eu(III), Sm(III) and Gd(III) from water—50% (v/v) methanol phase or water—50% (v/v) ethanol phase withPAN solutions in CCl₄ was examined. Separation factors for the following pairs of lanthanides(III) were determined: Eu-Sm, Eu-Gd, Sm-Gd, as well as Eu-Ln, Sm-Ln and Gd-Ln, where:Ln=Tb, Ho, or Lu; their changes with respect to the composition of the polar phase were also estimated.

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Der Einfluß von Methanol und Ethanol auf die Effektivität der Extraktion der Lanthaniden mit Lösungen von 1-(2-pyridylazo)-2-naphthol (PAN) in Tetrachlorkohlenstoff

Zusammenfassung Die Effektivität der Extraktion von Mikromengen Eu(III), Sm(III) und Gd(III) aus der Wasser-Methanol- und Wasser-Ethanol-Phase (50 vol. %), mit Hilfe vonPAN-Lösungen in CCl₄ wurde untersucht. Die Trennfaktoren für nachstehende Lanthaniden(III)-Paare: Eu-Sm, Eu-Gd, Sm-Gd und Eu-Ln, Sm-Ln, Gd-Ln(Ln=Tb, Ho oder Lu) wurden berechnet und ihre Änderungen in der Abhängigkeit von der polaren Phase geschätzt.

     

A new approach to arylaliphatic 1,5-, 1,6-, and 1,7-dicarbonyl compounds and their monoacetals based on direct anodic oxidation of 1-phenyl- and benzo[c]cycloalkenes

A new simple approach to -benzoylalkanals, 2-((-formylalkyl)benzaldehydes, and their monoacetals was developed based on direct anodic oxidation of I-phenylcycloalkenes and benzo[ccycloalkenes in methanol followed by acid hydrolysis of the electrolysis products. The target products are obtained in 53–72 % yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2044–2046, August, 1996.     

Novel liquid crystal compounds,derivatives of 2-pyrone

6-(4-n-Hexyloxyphenyl)- and 6-(4-n-decyloxyphenyl)-2-pyrones, which possess smectic and nematic mesomorphism, were synthesized.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1793–1794, October, 1994.     

One-pot synthesis of 3-(2-cyanophenyl)quinazolin-4(3H)-one

Anthranilonitrile reacting with formic acid at room temperature for three days gave 64% of 3-(2-cyanophenyl)quinazolin-4(3H)-one. Under similar conditions anthranilic acid. 4-nitroaniline, and 2,5-dichloroaniline were N-formylated in good yields.Institute of Organic Chemistry and Technology, Silesian Technical University, Krzywoustego, 4, 44–100 Gliwice, Poland; e-mail: wojtex@zeus.polsl.gliwice.pl. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 922–924, July, 2000.     

Reaction of furfurylidene acetone with Grignard reagents

The interaction of furfurylidene acetone with methylmagnesium iodide and ethylmagnesium halides has been studied. In the first case 2-methyl-4-(2-furyl)-3-buten-2-ol is formed as the product of 1,2-addition (yield 73 %). In the second case 4-(2-furyl)-2-hexanone (42 %) is the result of 1,4-addition, whereas 3-methyl-5-(2-furyl)-3-heptanol (45 %) is formed by consecutive 1,2- and 1,4-addition. In all cases the products of 1,3-addition were found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 921–923, May, 1993.     

Sensitized photomodification of oligonucleotide-binding proteins displayed on the eucaryotic cell surface

Interactions of double-stranded nucleic acids with cell surface proteins, which are involved in binding and transport of extracellular nucleic acids, were studied by the photoaffinity modification with a binary system of oligonucleotide conjugates. The photoreactive double-stranded complex involved an oligonucleotide template and two complementary to adjacent sequences oligonucleotide conjugates. One conjugate contained a photoreagent, viz., 4-azido-2,3,5,6-tetrafluorobenzaldehyde N-(3-aminopropionyl)hydrazone, at the terminus located in proximity to the terminus of another conjugate containing the sensitizer, viz., 9-aminomethylanthracene. Binding of photoreagent and the sensitizer to a single-stranded template yields the photoreactive center. Upon irradiation with visible light (400—580 nm), this photoreactive double-stranded complex forms covalent cross-linkages with oligonucleotide-binding surface proteins of eucaryotic SPEV cells.     

Nucleophilic addition to acetylenes in superbasic catalytic systems. 12. Vinylation of lupinine

The addition of a natural alkaloid lupinine to acetylene in the presence of superbasic catalytic systems (KOH—DMSO, KOBu^t—DMSO, KOH—dioxane) under elevated or atmospheric pressure affords O-vinyllupinine (in up to 88% yield), a promising optically active monomer and intermediate for the preparation of new quinolizidine alkaloids. The same vinyl ether was obtained (in 60% yield) by the reaction of lupinine with vinyl acetate in the presence of Hg(OAc)₂.     

Investigation of 2-[(<Emphasis Type="Italic">E</Emphasis>)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium as a new highly sensitive reagent for the spectrophotometric determination of nitrophenols

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of nitrophenols [picric acid (PA); dinitrophenols (DNP)] in wastewater samples. The method is based on the reaction of nitrophenols with 2-[(E)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3 H-indolium chloride reagent to form the colored ion associates, which are extracted by organic solvents. The molar absorptivity of the ion associates of PA with the investigated reagent ranges from 8.3×10⁴ to 11.3×10⁴ L mol^–1 cm^–1, depending on the extractant. Because only PA is extracted in an acidic medium with the investigated reagent, but both PA and DNP are extracted in an alkaline medium, it is possible to determine both substances in a mixture. Appropriate reaction conditions have been established. The absorbance of the colored extracts obeys Beers law in the range of 0.04–4.58 mg L^–1 PA, 1.0–18.4 mg L^–1 2,4-DNP and 1.2–14.7 mg L^–1 2,6-DNP, respectively. The limit of detections, calculated from a blank test (n=10; P=0.95), are 0.05 mg L^–1 PA, 0.9 mg L^–1 (2,4-DNP), and 1.1 mg L^–1 (2,6-DNP), respectively.     

Enantioselective chromatography of chiral chalcon-tricarbonylchromium complexes and their use in stereoselective Michael addition

Summary The enantiomeres of the title compounds1–8 could be separated by enantioselective chromatography on microcrystalline triacetylcellulose in ethanol. A high stereoselectivity of the Michael addition of dimethylmalonate was observed only for theortho-substituted complexes1,2 and3, while the selectivity decreased withmeta-substituted substrates. A synthesis of 3-(ortho-dimethylaminophenyl)-tricarbonylchromium-1-phenyl-2-propenone (4) and 3-(meta-dimethylaminophenyl)-tricarbonylchromium-1-phenyl-2-propenone (8) is described. Methods for the estimation of diastereomeric excess (d.e.) and — after decomplexation — enantiomeric excess (e.e.) are compared. The absolute chiralities of complexes were determined by optical comparison and by chemical correlation.

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Enantioselektive Chromatographie von chiralen Chalcon-tricarbonylchrom-Komplexen und ihre Verwendung in stereoselektiven Michael-Additionen

Zusammenfassung Die Enantiomeren der im Titel genannten Verbindungen1–8 wurden durch enantioselektive Chromatographie an mikrokristalliner Triacetylcellulose in Ethanol getrennt. Die Michael-Addition von Malonsäuredimethylester an dieortho-substituierten Komplexe1,2 und3 verläuft stereospezifisch, während aus denmeta-substituierten Komplexen Gemische der Diastereomeren erhalten werden. Die Darstellung von 3-(ortho-Dimethylaminophenyl)-tricarbonylchrom-1-phenyl-2-propenon (4) und 3-(meta-Dimethylaminophenyl)-tricarbonylchrom-1-phenyl-2-propenon (8) wird beschrieben. Methoden zur Bestimmung des diastereomeren Überschusses (d.e.) und — nach Dekomplexierung — des enantiomeren Überschusses (e.e.) werden einer kritischen Bewertung unterzogen. Die chiroptischen Eigenschaften und die Absolutkonfigurationen der Komplexe wurden bestimmt; letztere durch optischen Vergleich und/oder chemische Korrelation.

     

Organosoluble and light-colored fluorinated polyimides based on 9,9-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]fluorene and aromatic dianhydrides

A novel fluorinated diamine monomer, 9,9-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]fluorene (II) was prepared via the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride with 9,9-bis(4-hydroxyphenyl)fluorene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Polyimides V were synthesized from diamine II and various aromatic dianhydrides III _a-f via thermal imidization. These polymers had inherent viscosities ranging from 0.84 to 1.03 dL/g and were soluble in a variety of organic solvents such as NMP, DMAc, DMF, and DMSO, and some could even be dissolved in less polar solvents such as m-cresol, pyridine, and dioxane. Polyimide films V _a-f had tensile strengths of 85–105 MPa, elongations to break of 7–9%, and initial moduli of 2.13–2.42 GPa. The glass transition temperature of these polymers were in the range of 277–331 °C, their 10% weight loss temperatures were in the range of 539–594 °C in nitrogen and above 544 °C in air, and their char yields at 800 °C in nitrogen ranged between 55–65 wt%. Compared with nonfluorinated polyimides VI, V showed better solubility and lower color intensity. Low dielectric constants (2.68–2.85 at 1 MHz) and low moisture absorptions (0.12–0.24 wt%) were also observed. In particular, V _c-f afforded lightly-colored films, which had cutoff wavelengths lower than 385 nm and b* values ranging from 6 to 22.     

Investigation of neoascorbigen

The synthesis of N-methoxyascorbigen (neoascorbigen) — a natural substance from plants of the Cruciferae family — and also N-ethoxyascorbigen is described. In an acidic media under drastic conditions N-alkoxyascorbigens undergo transformations with the release of ascorbic acid and the formation of oligomers of 1-alkoxy-3-methyleneindolenine or with opening of the lactone ring, decarboxylation, and dehydration and the formation of 2-hydroxy-3-(1-alkoxy-3-indolyl)-4-hydroxymethylcyclopent-2-enone. Amides of neoascorbigen, 3-O-methylglycoside of N-ethoxyascorbigen, and the product of the reduction of N-ethoxyascorbigen by sodium borohydride were obtained for the first time.Scientific-Research Institute of the Search for New Antibiotics, Russian Academy of Medical Sciences, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 178–186, February, 2000.     

Conformations of Z- and E-isomers of some chiral (1R,4R)-2-arylidene-p-menthan-3-ones

The ¹Í NMR method in combination with molecular simulation was used to study conformations of Z- and E-isomers of (1R,4R)-cis-2-(4-methoxyphenyl)benzylidene-p-menthan-3-one. In solutions the Z-isomer, unlike the conformationally uniform Å-isomer, is an equilibrium mixture of chair conformers with the substantial predomination of one form with the axially oriented methyl and equatorial isopropyl groups (75—78%). The enone group is more nonplanar in the Z-isomer than in the Å-isomer. For the isopropyl fragment, the equiprobable existence of trans- and two gauche-rotamers for the Z-isomer and a substantial predomination of gauche-forms in the case of the E-isomer were established.     

Complex formation of certain rare earth metals with 1-(2-pyridylazo)-2-naphthol (PAN) in alcohol-water solutions

The formation ofPAN complexes in the systems:Ln(III)—PAN—alcohol—water [whereLn(III) = Pr, Nd, Sm, Eu, Gd, Tb, alcohol - ethanol andLn(III) = Eu, alcohol =n-propanol, isopropanol] was investigated by a spectrophotometric method. Equilibrium constants for the reactionLn ³⁺+HLLnL ²⁺+H⁺ (HL =PAN) and stability constants of complexesLnL ²⁺ are reported.

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Komplexbildung einiger Seltenerdmetalle mit 1-(2-Pyridylazo)-2-naphthol (PAN) in alkoholisch-wäßrigen Lösungen

Zusammenfassung Die Bildung der Komplexe vonPAN in den SystemenLn(III)—PAN—Alkohol—Wasser [Ln(III) = Pr, Nd, Sm, Eu, Gd, Tb, Alkohol = Ethanol undLn(III) = Eu, Alkohol =n-Propanol, Isopropanol] wurde mit einer spektrophotometrischen Methode untersucht. Die Gleichgewichtskonstanten der ReaktionenLn ³⁺+HLLnL ²⁺+H⁺ (HL =PAN) und die Stabilitätskonstanten der KomplexeLnL ²⁺ wurden berechnet.

     

Enantioselective syntheses of no-carrier-added (n.c.a.) (s)-4-chloro-2-[f] fluorophenylalanine and (s)-(α-methyl) -4-chloro-2-[f]fluorophenylalanine

(S)-4-Chloro-2-fluorophenylalanine and (S)-(α-methy)-4-chloro-2-fluorophenylalanine were synthesized and labeled with no carrier added (n.c.a.) fluorine-18 through a radiochemical synthesis relying on the highly enantioselective reaction between 4-chloro-2-[¹⁸F]fluorobenzyl iodide and the lithium enolate of (2S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3-methyl-1,3-imidazolidine-4-one for (S)-4-chloro-2-[¹⁸F]fluorophenylalanine and (2S,5S)-1-(tert-butyloxycarbonyl)-2-(tert-butyl)-3,5-dimethyl-1,3-imidazolidine-4-one for (S)-(α-methyl) -4-chloro-2-[¹⁸F] fluorophenylalanine. Quantities of about 20–25 mCi were obtained at the end of sy nthesi s, ready for injection after hydrolysis and high performance liquid chromatography (HPLC) purification, with a radiochemical yield of 17%–20% corrected to the end of bombardment after a total synthesis time of 90–105 min from [¹⁸F] fluoride. The enantiomeric excesses were shown to be 97% or more for both molecules without chiral separation and the radiochemical and chemical purities were 98% or better.     

X-ray Crystal and Ab Initio Structures of 3′,5′-di-O-Acetyl-N(4)-Hydroxy-2′-Deoxycytidine and Its 5-Fluoro Analogue: Models of the N(4)-OH-dCMP and N(4)-OH-FdCMP Molecules Interacting with Thymidylate Synthase

The crystal and molecular structures of the 3′,5′-di-O-acetyl-N(4)-hydroxy-2′-deoxycytidine molecule and its 5-fluoro congener have been determined by X-ray single crystal diffraction. The 3′,5′-di-O-acetyl-N(4)-hydroxy-5-fluoro-2′-deoxycytidine molecule crystallizes in the space group C2 with the following unit cell parameters: a = 21.72 Å, b = 8.72 Å, c = 8.61 Å, and β = 90.42^∘. 3′,5′-di-O-acetyl-N(4)-hydroxy-2′-deoxycytidine also belongs to the monoclinic space group C2 and the unit cell parameters are: a = 39.54 Å, b = 8.72 Å, c = 22.89 Å, and β = 95.26^∘. The non-fluorine analogue demonstrates a rare example of crystal structure with five symmetry-independent molecules in the unit cell. All the molecules in both crystal structures have the sugar residue anti oriented with respect to the base, as well as have the N(4)-OH residue in cis conformation relatively to the N(3)-nitrogen atom. In addition to the molecular geometries from X-ray experiment, the optimized molecular geometries have been obtained with the use of theoretical ab initio calculations at the RHF/6-31G(d) level. The corresponding geometric parameters in the molecules of 3′,5′-di-O-acetyl-N(4)-hydroxy-2′-deoxycytidine and its 5-fluoro congener have been compared. The differences including the C(5)=C(6) bond shortening and C(4)—C(5)—C(6) angle widening in the fluorine analogue are discussed in this paper in relation to the molecular mechanism of enzyme, thymidylate synthase, inhibition by N(4)-hydroxy-2′-deoxycytidine monophosphate and its 5-fluoro congener.