Synthesis and magnetooptical properties of mesomorphic complexes of lanthanides with β-aminovinyl ketones

Complexes of the composition L(LH)₂Ln(NO₃)₂ (Ln = La, Dy, Gd, Er, Eu, or Tb) were obtained by the reaction of -aminovinyl ketone (LH) with rare earth metal nitrates. All the compounds synthesized are thermotropic liquid crystals having the smectic S_A phase. The values of magnetic anisotropy of these complexes measured by magnetic birefringence are fairly high.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2331–2333, September, 1996.     

Synthesis and liquid-crystalline properties of substituted β-aminovinyl ketones and their complexes with copper(ii)

Mesogenic complexes were synthesized by the reaction of -aminovinyl ketones with copper(ii) acetate. On going from the ligands to complexes, the temperature of phase transitions increases and the nematic phase disappears. The initial members of the homological 1-(4-nonyloxyphenyl)-3-(4-methoxyphenylamino)-1-propen-1-one series demonstrate the alternation of clearing temperatures, which is absent for the corresponding copper(ii) complexes.     

Synthesis and structures of nickel(ii) complexes with thioether-containing β-aminovinyl ketones

New ligands, viz., thioether-containing -aminovinyl ketones, and Ni^II complexes with these ligands were synthesized. The compounds were characterized by X-ray diffraction analysis, EXAFS, NMR, and IR spectroscopy, and magnetochemistry.     

Synthesis of aryl-β-chlorovinyl ketones

Summary A method was developed for the synthesis of aryl--chloxovinyl ketone by condensation of substituted acetophenones with ethyl formale followed by treatment of the resultant hydroxymethylene ketone with thionyl chloride.     

Synthesis of alkyl-α,α-dimethylcyclopropanemethanols and alkylcyclopropyl methyl ketones

Russian Chemical Bulletin -     

Synthesis and anticancer activity of conformationally constrained Smac mimetics containing pseudo β turns

Herein, we report synthesis and in vitro anticancer activity of conformationally constrained Smac mimetics containing reverse turn inducing motifs “Ant-Pro” and “^sAnt-Pro”. The synthesis of Smac analogs with diverse hydrophobic groups at the C-terminus was carried out using solution phase peptide synthesis. The synthesis of Ant-Pro containing analogs 3a–j was carried out by ring opening of benzoxazinones 7a–c, whereas, their sulfonamide counterparts 4a–h were synthesized by using routine acid-amine coupling reaction. In vitro anticancer studies against breast cancer cell line MDA-MB-231 revealed that some of the new analogs had better anticancer activity than the standard AVPI Smac tetrapeptide.     

Synthesis and properties of cross-conjugated ��,�ء�-bis-dimethylamino ketones and dinitriles with N-acetyl- and N-benzylpiperidine cycles

Reactions of N-acetyl- and N-benzyl-4-piperidones with aminal of ??-dimethylaminoac-rolein yielded ketocyanines bearing piperidine cycle. Reaction of 3-dimethylamino-1,1,3-trimethoxypropane with 1-acetylpiperidin-4-ylidenemalononitrile in the presence of ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF₄), resulted in cross-conjugated ??,???-dimethylamino dinitrile. Protonation of ketocyanines bearing N-acetyl- and N-benzyl-piperidine cycles with Et₂O·HBF₄ (1 equiv.) furnished piperidinium salts, while protonation of the latter with Et₂O·HBF₄ (2 equiv.) afforded doubly charged 4-hydroxypolymethine salts. Unlike protonation, reaction of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-acetylpiperidin-4-one with Me₂SO₄ involved only the oxygen atom and led to a singly charged 4-methoxypolymethine salt. Methylation of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-benzylpiperidin-4-one with Me₂SO₄ (1 equiv.) involved cyclic nitrogen atom and resulted in piperidinium salt; heating of the latter with the excess of Me₂SO₄ afforded doubly charged bis-methoxysulfonate. Starting from 4-methoxytetrahydropyridinium salts, meso-methoxythiapentacarbocyanine dyes were synthesized.     

Synthesis and hetero-Diels-Alder reactions of (E)-α-perfluoroalkanesulfonyl-α,β-unsaturated ketones

Catalyzed by ammonium acetate, the Knoevenagel reactions of β-keto perfluoroalkanesulfones 1 with aromatic aldehydes 2 afforded α-perfluoroalkanesulfonyl-α,β-unsaturated ketones 4 in moderate to good yields. The possible mechanism for the reactions was proposed. These fluorine-containing α,β-unsaturated ketones, which are electron-poor 1-oxa-1,3-butadienes, could be used in inverse electron demand hetero Diels-Alder (HDA) reaction with electron-rich olefins to give tetrasubstituted dihydropyrans 6 in quantitative yields.     

Synthesis and properties of 8-phenylindolo-3,3′-trimethinecyanines

The condensation of 1-methyl-2-aryl-3-(2-benzoylvinyl)indoles with substituted indoles in acetic anhydride in the presence of a mineral acid afforded 8-phenylindolo-3,3-trimethinecyanines. Their spectral, polarographic, and photographic properties were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 499–501, April, 1992.     

Synthesis and spectrophotometry study of the acid-base properties of nitro-substituted 5-phenyl-β-octaalkylporphines

10,15-Dinitro-5-phenyl-2,3,7,8,12,13,17,18-octamethylporphine, 10,15,20-trinitro-5-phenyl-2,3,7,8,12,13,17,18-octamethylporphine, and 10,15,20-trinitro-5-(4-nitrophenyl)-2,3,7,8,12,13,17,18-octamethylporphine were synthesized and identified by electronic absorption, IR, and ¹Н NMR spectroscopy. The acid–base properties of the synthesized compounds were studied by spectrophotometric titration in HClO₄–acetonitrile and 1,8-diazabicyclo[5.4.0]undec-7-ene–acetonitrile systems at 298 K. Parameters of the electronic absorption spectra and concentration ranges of existence of the mono- and diprotonated, as well as mono- and dideprotonated forms of the corresponding ligands and the acid and base dissociation constants of the latter were determined. Comparative analysis of the effect of nitro groups on the reactivity of the synthesized compounds was performed.     

Synthesis of Z-β-siloxyacrylonitriles and study of their dienophilic properties

A general method for the synthesis of Z-β-siloxyacrylonitriles from isoxazoles is reported. Their dienophilic activity is also described.     

Anionic cyclizations of aromatic ester dithioacetals with facially biased α,β-unsaturated ketones

Cyclopent-2-enones bearing a plane-nonsymmetric oxygen function on C-4 reacted efficiently with anions derived from aromatic ester dithioacetals to provide annulated products in a highly diastereoselective fashion. Whereas the anion of a dimethoxy aromatic ester dithiolane more rapidly reacted by an alternative intramolecular pathway, the anion of the corresponding aromatic ester dithiane was suitable for the intermolecular cyclization.     

Synthesis of epoxycarbonyl pyrroline derivatives by cycloaddition of benzonitriliop-nitrophenyl-methanide toα,β-unsaturated epoxy ketones

The cycloaddition reaction of benzonitriliop-nitrophenylmethanide to , -unsaturated epoxy ketones gives a mixture of stereoisomeric epoxycarbonyl pyrrolines. Only one of the isomers was isolated as pure compound. The structure, stereo- and regiochemistry of the isolated products was established by NMR and NOE measurements as well as by mass spectral data.Department of Organic Chemistry, Belarus State University of Technology, Minsk 220630, Belarus, Dipartimento di Scienze Chimiche, Universita, 95125, Catania, Italy. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 630–633, May, 1998.     

Synthesis of β-carbolines from aldehydes and ketones via the α-siloxy α,β-unsaturated esters

We report an efficient method for the synthesis of β-carbolines from α-siloxy α,β-unsaturated esters, which are accessible from a variety of aldehydes and ketones.     

Synthesis and some properties of diethoxyaluminum α,α-dimethylbenzyl peroxide

Summary The previously undescribedorganoaluminum peroxide of composition (C₂H₅O)₂AlOOC₉H₁₁ was synthesized, and some of its properties were studied.     

Synthesis and properties of the first Möbius annulenes

Heilbronner in 1964 predicted that annulenes with ".. a planar perimeter of N=4r AO's, which would yield an open shell configuration when occupied by 4r electrons, can be twisted into a closed shell M?bius strip perimeter without loss in pi electron energy". We have been able to synthesize the first [4n]annulene with such a M?bius topology and now present further M?bius isomers and the details of their preparation as stable compounds. To address the question whether the twist in the pi system has an effect on the properties we systematically investigate energy, geometry and magnetic parameters of a large number isomers of [16]annulenes. The M?bius twisted annulenes are consistently more aromatic than the non-twisted isomers. This is true for the parent as well as our benzoannelated systems. Our results are in contrast to those published recently by C. Castro, W. L. Karney, P. von R. Schleyer et al.     

Synthesis and structure of some 8α-analogs of steroid estrogens

The distances between the protons of four 8α-analogues of steroid estrogens as determined by X-ray data are consistent with the calculated values obtained by ab initio, PM3 and MM+ methods, that can be used for docking of these stereochemical analogs onto α-estrogen receptors.     

Synthesis and substitution reactions of β-alkoxyvinyl bromodifluoromethyl ketones

β-Alkoxyvinyl bromodifluoromethyl ketones 1a, 1b and 1c were synthesized by the reaction of bromodifluoroacetic anhydride with appropriate vinyl ethers in high yields. The acyclic enone 1a reacted with amines to give the corresponding β-aminovinyl bromodifluoromethyl ketones 2 in good yields. The reaction of 1a with electrophilic reagent ICl yielded α-iodoenone 4. The substitution reaction of the cyclic enones 1b and 1c with thio-nucleophiles gave the corresponding difluoromethylene thioethers 6. The three-component reactions of 2 with primary amines and formaldehyde gave multifunctional 1,2,3,4-tetrahydropyrimidine 3 in moderate yields.     

Sulfanyl-methylene-5(4H)-oxazolones and β-sulfanyl-α-nitroacrylates as appealing dienophiles for the synthesis of conformationally constrained cysteine analogues

A new class of masked constrained cysteine derivatives containing the norbornen/ane scaffold were prepared by the way of Diels–Alder cycloaddition reaction by exploitation of two different dienophiles, sulfanyl-methylene-5(4H)-oxazolones and β-sulfanyl-α-nitroacrylates. The new norbornen/ane amino acid derivatives can be considered versatile building blocks due to the presence of the α,α-disubstituted amino acid function, suitable for peptide synthesis, but also by the carbon–carbon norbornene double bond, which could be variously functionalized.