Preparation and Cytotoxicity of Novel Aliphatic Polycarbonate Synthesized from Dihydroxyacetone

A new cyclic carbonate, 2,2-ethylenedioxypropane-l,3-diol carbonate (EOPDC), was synthesized through a two-step reaction from dihydroxyacetone dimer, and polymerized in bulk initiated by Sn(Oct)2 to give a high molecular weight polycarbonate. The structure of monomer and the polymer were characterized by FT-1R, ^1H NMR, ^13C NMR. The cytotoxicity of the obtained polycarbonate was investigated by MTT assay.     

Synthesis and Characterization of Novel Aliphatic Polycarbonates Bearing Pendant Allyl Ether Groups

To fulfill the diverse requirements in surgery and medicine, biomedical polymers have been drawing interests and attentions increasingly since the last decade1. In these fields, aliphatic carbonates have been proved to be a kind of material with excellent…     

Iridium-Catalyzed β-Alkynylation of Aliphatic Oximes as Masked Carbonyl Compounds and Alcohols

An Ir-catalyzed C(sp³)−H alkynylation of aliphatic ketones, aldehydes, and alcohols was achieved by using the corresponding oxime derivatives and a Ir^III catalyst. This general reaction is selective towards primary C(sp³)−H bonds and can be used for the late-stage C−H alkynylation of complex molecules.     

New Aliphatic Alcohol and Ester Constituents from Rice Hulls of Oryza sativa

Six new aliphatic alcohol and ester compounds of n-octacos-9-enyl propionate （1）, 4-（3-formylheptyl）cyclohexyl 4-（cyclohexylcarbonyloxymethyl）cyclohexyl-carboxylate （2）, n-hentriacont-25-en-5α-ol （3）, n-hexetriacont-9,26-dien-8α,11β,23α-triol （4）, n-tetracontan-15α-ol （5） and n-tritetracontan-5α-ol （6） were isolated from the hulls of Oryza sativa. The structures were established on the basis of spectroscopic analysis.     

6,6′-Dibromo-3,3′-dimethoxy-2,2′-dihydroxy-1,1′-biphenyl: preparation and resolution

A pratical route to prepare the title biphenyl 1 starting from 3,3′,2,2′-tetramethoxy-1,1′-biphenyl 2 is described. Resolution of 1 was achieved by its conversion into the corresponding diastereomeric menthyldicarbonate. The absolute configuration of (P)-(+)-1 was confirmed by X-ray analysis of the related diastereomer.     

Syntheses and Crystal Structures of 4,4′Diformyl-diphenoxyethane and 4,4′4′′-Triformyl-triphenoxytriethylamine

1 INTRODUCTION With the methods of [2+3] and [1+1] tripodal condensation of polyaldehyde with polyamine, many Schiff bases and their relative reduced polyaza cryptands have been facilely synthesized in high yields[1～5]. In this one-step route, some metal ions such as alkali[2, 6, 7], alkali earth[8], rare earth[9, 10] and other transition ions[4, 11, 12] were used as templates[13, 14]. Formerly, the dialdehydes are needed to be rigid structures[15] to prevent themselves from polymeri…     

Calorimetric study of 2′-methylacetophenone and 4′-methylacetophenone

Values of the condensed phase standard (p = 0.1 MPa) molar enthalpy of formation for 2′- and 4′-methylacetophenones were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The values of the standard molar enthalpy of vaporization, at T = 298.15 K, were measured by Calvet microcalorimetry. Combining these two values, the following enthalpies of formation in the gas phase, at T = 298.15 K, were then derived: 2′-methylacetophenone, –(115.7 ± 2.4) kJ · mol⁻¹, and 4′-methylacetophenone, –(122.6 ± 2.4) kJ · mol⁻¹. Substituent effects are discussed in terms of stability and compared with other similar compounds. The value of the standard molar enthalpy of formation for 3′-methylacetophenone was estimated from isomerization schemes.     

Interaction between a Decahydro-closo-Decaborate(2–) Anion and Aliphatic Carboxylic Acids

Interaction between a closo-decaborate anion B₁₀H^2– ₁₀and carboxylic acids RCOOH (R = H, CH₃, C₂H₅, iso-C₃H₇, C₄H₉) is studied. The mono-, di- tri- and tetrasubstituted products B₁₀H_{10 – n} (OCOR)^2– _n are formed in sequence with the temperature growth. The reaction follows an essentially regioselective mechanism: only one of all possible isomers forms at every stage of the process. The respective hydroxy-closo-decaborates B₁₀H_{10 – n} (OH)^2– _n were prepared by alkaline hydrolysis in aqueous and nonaqueous solutions. All the compounds were identified by chemical analysis and ¹¹B NMR and IR spectroscopy. The crystal structure of [Pb(Bipy)(DMF)(B₁₀H₉OH)] · DMF was determined by X-ray diffraction.     

Synthesis and properties of 2,2′-dipyridyl and 4,4′-dipyridyl complexes with thulium salts

Summary New complexes of 2,2-dipyridyl and 4,4-dipyridyl with thulium salts TmX ₃ (whereX=Cl^–, Br^–, NO ₃ ^– , NCS^–, and ClO ₄ ^– ) have been prepared and their solubilities in water at 21 °C were determined. The IR spectra of these compounds are discussed. The conditions of thermal decomposition of the complexes were also studied.

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Synthese und Eigenschaften von 2,2-Dipyridyl- und 4,4-Dipyridylkomplexen mit Thuliumsalzen

Zusammenfassung Es wurden neue 2,2-Dipyridyl- und 4,4-Dipyridyl-Komplexen mit Thuliumsalzen TmX ₃ (X=Cl^–, Br^– No ₃ ^– , NCS^–, ClO ₄ ^– ) dargestellt und ihre Wasserlöslihkeit bei 21 °C bestimmt. Die IR-Spektren werden diskutiert. Das thermische Verhalten der erhaltenen Komplexe wurde untersucht.

     

Cotton-mouton constants and spatial structure of 2,2′- and 4,4′-dipyridyls and their salts in solutions

Magnetic birefringence has been used in studying the spatial structure of a series of dipyridyl derivatives in hydrochloric acid solutions, and also some of their quaternary salts in water. It has been shown that when the change is made from the molecular forms of the 2,2- and 4,4-dipyridyls to their protonated mono and bis derivatives, the angles of rotation of the aromatic rings are very little changed; in the methylated cation, the degree of acoplanarity increases.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2771–2775, December, 1991.     

Efficient CuCl-Catalyzed Selective and Direct Oxidation of β- and γ-Substituted Aliphatic Primary Alcohols to Carboxylic Acids

A new procedure for the selective and direct oxidation of aliphatic primary alcohols having substitution at β- and γ-positions to corresponding carboxylic acids was developed using a catalytic amount of ligand and additive-free CuCl with anhydrous ^t BuOOH in acetonitrile solvent under very mild reaction conditions. This procedure is very simple and mild and works efficiently without any additives at room temperature.     

1′-Azido- and 1′-amino-1,3-dioxolan-4-ones

1,3-Dioxolanone alcohols, prepared via the addition of chiral lithium enolates of 1,3-dioxolan-4-ones to aldehydes, are suitable intermediates for the synthesis of chiral trisubstituted isoserines or trisubstituted 3-hydroxy-β-lactams. In particular, the methyl ester of 2-methyl-3-(2-furyl)isoserinic acid and two 3-methyl-3-hydroxy-β-lactams bearing either a 2-furyl or a phenyl substituent at C-(4) have been prepared. The (2R,3S) stereochemistry of the isoserine, and the (3R,4S) stereochemistry of the two β-lactams is that required for the synthesis of taxoid analogues having the side-chain with the proper (2′R,3′S) configuration.     

Aliphatic Phosphenium Canon Featuring A P-S Bond

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Complexation of Aliphatic Alcohols by α- and β-Cyclodextrins and their Partial Methylated Derivatives in Aqueous Solution

The complexation of aliphatic alcohols by α- and β-cyclodextrins and their partially methylated derivatives has been studied by means of calorimetric titrations in aqueous solution. The methyl substituents have no pronounced influence upon the complex formation. α-Cyclodextrin and the partially methylated derivative form with only few exceptions more stable than β-cyclodextrin. With increasing chain length of the alcohols the values of the stability constants and reaction enthalpies increase in case of the complex formation with α-cyclodextrin and partially methylated α-cyclodextrin. In contrast the complex formation becomes disfavoured by the reaction entropy with an increasing number of methylene groups. The values of the reaction enthalpies with the β-cyclodextrins are close to zero. Thus the complexation is only favoured by entropic contributions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Concise Synthesis and Cellular Evaluation of 3′-Formyl-4′,6′-dihydroxy-2′-methoxy-5′-methylchalcone (FMC) and Its Analogues

3′-Formyl-4′,6′-dihydroxy-2′-methoxy-5′-methylchalcone (FMC) was a natural product isolated from Cleistocalyx operculatus. A four-step synthetic strategy toward FMC and its four analogues (1b–1e) was first developed. All compounds were synthesized from commercially available 2,4,6-trihydroxyacetophenone; formylation at 3′ position under Vilsmeier–Haack conditions was followed by the introduction of a methyl group at 5′ position. The key step of selective methylation at 2′ position was achieved by trimethylsilyldiazomethane (TMSCHN₂). Then substituted aromatic aldehydes were condensed through Claisen–Schmidt reaction in the presence of potassium hydroxide. All structures were confirmed by ¹H NMR, ¹³C NMR, and high-resolution mass spectra. FMC and analogues were screened for their antiproliferative activity.     

Vibrational spectra and molecular configuration of 2,2′-diphenyl ethyl alcohol and 2,2′-diphenyl ethylamine

The Raman and IR spectra of 2,2′-diphenyl ethyl alcohol and 2,2′-diphenyl ethylamine have been analyzed assuming the phenyl rings vibrate independently. Complete vibrational assignment show that some ring modes for both the molecules are found to appear in pairs. Possible orientation of the two rings with respect to the tetragonally hybridized carbon atom has been discussed. Two probable cases of Fermi resonance have been observed. The general nature of the ring modes to exhibit a pair of frequencies in some diphenyl-type molecules has been described.     

Synthesis of 5′-benzoyl-2′-hydroxychalcones and related flavonoid compounds

Summary 5 -Benzoyl-2 -hydroxychalcones were synthesized by the condensation of 5 -benzoyl-2 -hydroxyacetophenone with aromatic aldehydes in presence of an ethanolic solution of potassium hydroxide. Derivatives of 6-benzoylflavonoids were prepared from chalcones.     

Electrochemical and spectroscopic properties of poly-4,4′-dialkoxy-2,2′-bipyrroles

The structure and the electrochemical and spectral properties of two conductive electrochemically polymerized substituted bipyrroles 4,4′-methoxy-2,2′-bipyrrole and 4,4′-buthoxy-2,2′-bipyrrole were studied and compared. The polymers were characterized by cyclic voltammetry, FT-Raman spectroscopy, scanning electron microscopy, and in situ conductivity measurements at different pH and redox state.