Synthesis of polynucleotide analogs by grafting optically active nucleic acid base derivatives onto polyethylenimine

Polynucleotide analogs with a polyethylenimine backbone and optically active thymine- and adenine-containing pendants and their model compounds were synthesized. The pendants were prepared by the addition reaction of the nucleic acid base to ethyl crotonate. The ammonium salt of 3-(adenin-9-yl)butyric acid was employed to replace its free acid for the formation of diastereomeric salt with brucine. Fractional crystallization of the diastereomeric salt generates the partially resolved enantiomers. The solubility difference between the racemic mixture and its enantiomer was utilized to obtain the pure enantiomers. The active esters of the pendants were prepared. Grafting reactions were carried out by the reaction of active esters with PEI at room temperature. Completely grafted polymers were obtained.     

Synthesis of optically active polynucleotide analogs with polytrimethylenimine backbones and thymine moieties

Polynucleotide analogs with polytrimethylenimine backbones and optically active 2-(thymin-1-yl)propionic acids as pendants were prepared. Linear polytrimethylenimines were obtained by ring-opening polymerization of 2-phenyl-5,6-dyhydro-4H-1,3-oxazine and subsequent hydrolysis of the resulting polymers. 2-(Thymin-1-yl)propionic acids were reacted with N-hydroxy succinimide to form active esters. Optical purities of active esters were determined by NMR with chiral chemical shift reagents. The polynucloetide analogs and related monomer and dimer model compounds were prepared by grafting reactions using active esters.     

Grafting of optically active nucleic acid base derivatives onto poly(vinylamine) as polynucleotide analogs

Polynucleotide analogs consisting of poly(vinylamine) as the backbone and optically active thymine and adenine derivatives as the pendants were synthesized. The pendants were prepared by the addition reaction of the nucleic acid base to ethyl crotonate followed by hydrolysis. The pendants were resolved using brucine as the resolving agent and an acetone-water mixture as the fractional crystallization solvent. The active esters of the pendants also were prepared. Poly(vinylamine) was isolated from water employing a weak acid, N-hydroxysuccinimide (HOSu), to protect the amino group of the poly(vinylamine). Model reactions for grafting were examined. Grafting reactions were carried out by reacting the active esters with the PVAm.6HOSu complex at room temperature.     

Synthesis of optically active polynucleotide analogs with poly(vinyl alcohol)s as backbones and adenine and 5-bromouracil derivatives as pendants

The optically active polynucleotide analogs were prepared by grafting nucleic acid base derivatives onto poly(vinyl alcohol). The (R)-ethyl 2-(5-bromouracil-1-yl)propanoate was obtained either by reaction of 5-bromouracil sodium salt with (S)-ethyl 2-[(methylsulfonyl)oxy]propanoate or reaction of 5-bromouracil with (S)-ethyl lactate in the presence of triphenyl phosphine and diethyl azodicarboxylate. Subsequent hydrolysis of the ester is aqueous acid provided the optically pure (R)-bromouracilypropanoic acid. The monomer model compounds were prepared by an esterification reaction of the pendant groups with 3-pentyl alcohol in the presence of dicyclohexylcarbodiimide and a catalytic amount of 4-pyrrolidinopyridine. Poly(vinyl alcohol) underwent reaction with the (R)-bromouracilylpropanoic acid or the (R)-adeninylpropanoic acid in the presence of dicyclohexylcarbodiimide and a catalytic amount of 4-pyrrolidinopyridine. The resulting polymers were optically active and percents grafting were almost quantitative.     

Synthesis and characterization of adenine base grafted polyacrylamides as polynucleotide analogs

The adenine base grafted polyacrylamides and their corresponding monomer model compounds were prepared and examined. The results suggest that the monomer model compounds exist in a preferred conformation, whereas the adenine base grafted polyacrylamides exist in a limited ordered conformation in an aqueous medium.     

Synthesis of optically active amphiphilic tetrathiafulvalene derivatives

The synthesis and characterization of novel chiral tetrathiafulvalenes bearing two long alkyl chains at one end of the π-electron rich unit and different functional groups—ester, acid or thiolate—at the other extreme is described. The synthetic method requires the preparation of 1,3-dithiol derivatives with two stereogenic centers. Different routes and reaction conditions were explored to form these compounds, whose optimized synthesis involved the nucleophilic substitution of a chiral bromo methylene derivative with tetrabutylammonium bis(2-thioxo-1,3-dithiole-4,5-dithiolate)zincate. The tetrathiafulvalenes were prepared by coupling the 1,3-dithiol derivative with 4,5-bis(methoxycarbonyl)-1,3-dithiol-2-one or 4,5-bis(2-cyanotehylthio)-1,3-dithiol-2-thione. The products were fully characterized, including by circular dichroism spectroscopy, which confirmed their optical activity. They are promising candidates to be used as building blocks in supramolecular materials for molecular electronics, to produce systems with unique electrical, magnetic or optical properties that stem from their chirality.     

Synthesis of optically active verrucarinic acid derivatives

Two syntheses of verrucarinic acid highlighting an oxidative cleavage of hydroxysulfides and use of mandelate esters for chromatographic resolution are reported.     

Etheno derivatives of adenine and cytosine (review)

The method of modification of heterocyclic bases of nucleic acids with chloroacetaldehyde and other α-halo carbonyl compounds is examined in this review. The mechanism, kinetics, and scope of the reaction, the chemical properties of modified derivatives of adenine and cytosine, and the possibilities of the application of etheno derivatives of adenine and cytosine in biochemistry and molecular biology are discussed. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 291–305, March, 1980.     

Synthesis of optically active trifluoromethylated indolizidine derivatives via stereoselective radical cyclization

[reaction: see text]. Asymmetric Michael reaction of lithiated trifluoroacetone SAMP-hydrazone with alkylidenemalonates gave addition products stereoselectively. Hydrolyzed enantiomerically pure ketoacids were cyclized to dihydropyridinones. N-Iodopropylation followed by radical cyclization gave optically active trifluoromethylated indolizidinones stereoselectively.     

Synthesis and optical properties of polyethylenimine containing L-proline and optically active thymine derivatives

Preparation and optical properties of linear polyethylenimine (PEI) containing L -(?)-N-[(?)-2-(thymin-1-yl) propionyl] prolyl group as grafting pendant, [P-(?)Pro-(?)T], and its related monomer and dimer model compounds are described. Hypochromic effects and circular dichroism of these compounds were compared with those of PEI containing (?)-2-(thymin-1-yl) propionyl group as grafting pendant, [P-(?)T], which has no L -proline ring as a spacing group. P-(?)Pro-(?)T showed no exciton coupling of B_2u π-π^* transition although it showed large hypochromicity in neutral aqueous solution, implying that the stacking of the bases has no screw sense.     

Ferrocene derivatives, LXXI; Stereochemistry of metallocenes, LVI Synthesis and structure of optically active ferrocenylaminoalcohols

The reaction of enantiomerically pure 1,2-(-N,N-dimethylamino)-tetramethylene ferrocene (4) with butyllithium and subsequent treatment with either benzophenone or paraformaldehyde has yielded the aminoalcohols 6–11. The absolute configurations of 4 and 6–11 were deduced from the X-ray structures of the (R,R)-tartrate of 4 (4-T) and the aminoalcohol 6. In addition the optical purity of 4 was shown to be at least 95% by transformation into the ketone 2. In solution the annelated six-membered ring in compounds 4 and 6–11 was found to adopt a preferred half-chair conformation very similar to that found in the solid state structures of 4-T and 6.     

Synthesis of optically active lipopeptide analogs from the outer membrane of Escherichia coli.

The synthesis of optically active lipopeptide derivatives has been accomplished by the use of chiral glycerol derivatives. Lipopeptide derivatives with (R)-glycerol moieties showed higher mitogenic activities than those with the (S)-configuration. N-2,2,2-Trichloroethoxycarbonyl lipopeptide derivatives increased mitogenic activity.     

相转移催化不对称碳烷化研究—光学活性的二氢吲哚酮类衍生物的合成

本文报道了手性季铵盐1-7催化溴代烷与1,3-二甲基-5-甲氧基-2-二氢吲哚酮(8)的不对称3-C烷化反应, 并通过研究不同的催化剂结构、溶剂、温度及溴代烷结构对产物光学活性的影响, 讨论了不对称诱导机理.     

Synthesis of polynucleotide analogs containing a polyvinyl alcohol backbone

Water soluble homo-base polynucleotide analogues were synthesized in which polyvinyl alcohol and partially phosphonated polyvinyl alcohol constituted the backbones,onto which were grafted uracil or adenine via 1,3-dioxane spacers formed by acetal formation with the 1,3-diol moieties in PVA. The resulting adenine-PVA polynucleotide analogs exhibited hyperchromic effects, which was not the case for the corresponding uracil compounds. Mixtures of the adenine- and aracil PVA-phosphate polynucleotide analogs in solutions exhibited characteristic S-shaped UV-absorbance vs temperature and melting curves with melting points at approximately 40 degrees C.     

Synthesis of optically active bihelicenols

All six stereoisomers of dimethyl 5,5′-dihydroxy-1,1′,12,12′-tetramethyl-[6,6′]bi(benzo[c]phenanthrenyl)-8,8′-dicarboxylate (bihelicenol) were synthesized by the oxidative coupling of methyl 8-hydroxy-1,12-dimethylbenzo[c]phenanthrene-5-carboxylate (helicenol), and their structures were determined by X-ray analysis.     

Synthesis of optically active penems

A general synthesis for optically active penems is described. Penems undergo a novel thermal isomerisation reaction.     

Synthesis of optically active lipoaminoacids

Conclusions S--(Distearoyl-L-phosphatidyl)--L-alanylglycerol and its R-isomer have been synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1098–1100, June, 1966.     

Synthesis of optically active methadones,LAAM and bufuralol by lipase-catalysed acylations

(R)- and (S)-Methadones and levo-α-acetylmethadol (LAAM) have been synthesised starting from lipase-catalysed acylation of dimethylaminopropan-2-ol. An approach to the synthesis of (R)-bufuralol is also presented.