Synthesis of isomeric 2-oxazolidinones from (1<Emphasis Type="Italic">R</Emphasis>,2<Emphasis Type="Italic">R</Emphasis>)-and (1<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-2-amino-1-(4-nitrophenyl)-1,3-propanediols

A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds was studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007.     

Diastereoselective reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with aromatic aldehydes. Synthesis of (1R,2R,4S,5S,8S)-2,8-diaryl-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3.3.0]octanes

We have synthesized a series of (1R,2R,4S,5S,8S)-2,8-diaryl-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3.3.0]octanes as a result of reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with aromatic aldehydes. The structure of the compounds obtained was established on the basis of ¹H NMR data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 757–763, May, 2006.     

A new synthesis ofE- andZ(-)(1R,3S)-2,2-dimethyl-3-(3,3,3-trifluoro-2-chloropropen-1-yl)cyclopropanecarboxylic acids from (+)-3-carene

A new synthesis ofE- andZ(-)(1R,3S)-2,2-dimethyl-3-(3,3,3-trifluoro-2-chloropropen1-yl)cyclopropanecarboxylic acids from (+)-3-carene in 21 % total yield was carried out.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 517–518, March, 1995.     

Enantiospecific synthesis of (S)-(+)-3-methylheneicosan-2-one, an analog of the sex pheromone of the German cockroach (Blatella germanica L.) from (−)-(1R,4S)-menthone

An enantiospecific synthesis of (S)-(+)-3-methylheneicosan-2-one, an analog of the sex pheromone of the German cockroach (Blatella germanica L.), was carried out through selective transformations of (3R,6S)-3,7-dimethyloctane-6-olide obtained from (−)-menthonevia the Baeyer—Villiger reaction. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1071–1073, May, 1997.     

Liquid chromatographic enantioseparation of β-blocking agents with (1R,2R)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propyl isothiocyanate as chiral derivatizing agent

The applicability of (1R,2R)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propyl isothiocyanate [(R,R)-DANI] as a recently developed chiral derivatizing agent for the enantioseparation of a series of β-blockers is described. The thiourea diastereomers formed were analyzed by reversed-phase high-performance liquid chromatography, mixtures of water and methanol or acetonitrile being used for elution. Conditions of derivatizations (temperature, reagent excess and reaction time) were optimized, and the effects of organic modifiers on the retention and separation were investigated; the diastereomers could readily be baseline separated with methanol-containing mobile phases with resolutions between 1.58 and 2.72.     

三有机锡（4R）-3-[[（2S）-5-氧-2-吡咯烷基]羰基]-4-噻唑烷甲酸酯的合成、结构和体外抗癌活性

利用三有机锡氢氧化物和手性配体（4R）-3-[[（2S）-5-氧-2-吡咯烷基]羰基]-4-噻唑烷甲酸（HL）反应合成了3个三有机锡（4R）-3-[[（2S）-5-氧-2-吡咯烷基]羰基]-4-噻唑烷甲酸酯R₃SnL[1,R=c-C₆H₁₁（a）,C₆H₅（b）,C₆H₅C（CH₃）₂CH₂（c）],通过元素分析、IR、¹H NMR和X-射线单晶衍射表征了其结构。化合物1a属正交晶系,P2₁2₁2₁空间群;化合物1b属单斜晶系,P2₁空间群。二者均为由羧基氧和内酰胺羰基氧桥联配位形成的右螺旋链状有机锡配位聚合物,锡原子具有五配位[SnC₃O₂]畸变三角双锥构型。化合物1a和1b对体外2种人癌细胞Colo205和Bcap37增殖均有强的抑制作用,其活性为1b >1a。     

利用甾体皂甙元氧化降解废弃物(R)-4-甲基-δ-戊内酯合成松叶蜂主要性信息素(2S,3S,7S)-3,7-二甲基-2-十五醇乙酸酯和丙酸酯

首次利用甾体皂甙元氧化降解废弃物(R)-4-甲基-δ-戊内酯合成了松叶蜂性信息素(2S,3S,7S)-3,7-二甲基-2-十五醇乙酸酯(2)和丙酸酯(3). 甾体皂甙元氧化降解废弃物(R)-4-甲基-δ-戊内酯首先被转化成为性质稳定易保存的(R)-5-溴-4-甲基戊酸甲酯(5), 化合物5经过偶联、还原、溴代、环氧加成开环和酰化反应给出目标分子. 本研究结果不仅为松叶蜂性信息素化合物2和3提供了一个简洁有效的合成方法, 同时也丰富了资源化学(即基于资源性化合物合理利用的有机合成化学)的内涵.     

新型1,3-二丁基咪唑离子液体中脂肪酶催化折分(R,S)-1-苯乙醇

设计合成6种采用不同1,3-二丁基咪唑阳离子和六氟磷酸(PF6-)或双三氟甲烷磺酰亚胺(TFSI-)阴离子的离子液体.以脂肪酶催化拆分1-苯乙醇为模型反应,分别考察介质、水含量和温度对反应的影响.结果表明,在1,3-二异丁基咪唑六氟磷酸盐([D(i-C4)Im][PF6])离子液体介质中酶的活性和反应性明显高于其它离子液体和正己烷.因此,[D(i-C4)Im][PF6]被确定为反应介质.在最佳条件下,初始反应速率是1.93μmol?mg-1?min-1,1-苯乙醇的转化率达50%,对映体过量值eep99%,酶的半衰期为348h,酶重复使用10次后活性没有明显减少.此外,圆二色谱、内源荧光光谱和光学显微镜研究表明,酶在[D(i-C4)Im][PF6]中保温6d后氨基酸残基的裸露程度略有增加,但其二级结构仍保持稳定,且以天然的折叠球形态存在.     

X-ray structural analysis of (1R,2R,4S,5S,8S)-2,8-bis(4-chlorophenyl)-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3,3,0]octane

The configuration of the asymmetric atoms in the molecule of (1R,2R,4S,5S,8S)-2,8-bis(4-chlorophenyl)-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3,3,0]octane has been determined using X-ray analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 930-934, June, 2006.     

The total synthesis of the archaebacterial C40-diol and its enantiomer based on (R)-5-acetoxy-4-methylpentanoic acid

Effective convergent syntheses of archaebacterial C₄₀-diol [(3R,7R,11S,15S,18S,22S, 26R,30R)-octamethyldotriacontane-1,32-diol] and its (3S,7S,11R,15R,18R,22R,26S,30S)-enantiomer have been accomplished using (R)-5-acetoxy-4-methylpentanoic acid as the only chiral building block. Both synthetic schemes include consecutive construction of mono- and diterpene fragments of the target molecules followed by dimerization using the Kolbe reaction or the oxidative self-condensation of the corresponding Grignard reagent.Deceased November 1, 1992.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1303–1309, July, 1993.     

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.     

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.     

[4+2]-Cyclodimer of sabinone: formation,crystal structure,and NMR spectra

Oxidation of (+)-sabinol, (1S,3R,5S)-1-isopropyl-4-methylidenebicyclo[3.1.0]hexan-3-ol, by active MnO₂ afforded not the expected sabinone but only its [4+2]-cyclodimer. The molecular structure of the latter was established by X-ray diffraction analysis. The ¹H and ¹³C NMR spectra of this cyclodimer were interpreted using 2D NMR spectroscopy.     

High-performance liquid chromatographic separation of unusual amino acid enantiomers derivatized with (1S,2S)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propyl-isothiocyanate

Summary A new chiral derivatizing agent (CDA), (1S,2S)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propylisothiocyanate, (S,S)-DANI, was applied to the separation of the enantiomers of unusual amino acids containing two chiral centers. Different β-methyl-α-amino acids (β-MePhe, β-MeTyr and β-MeTrp) and β-amino acids with cycloalkane skeletons (2-aminocyclopentanecarboxylic acid and 2-aminocyclohexanecarboxylic acid) were derivatized and the thiourea derivatives produced were separated by reversed-phase high-performance liquid chromatography. The applicability of this new CDA in the separation of unusual amino acids is demonstrated. The four stereoisomers of the investigated amino acids (except β-MePhe) could be separated in one chromatographic run. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

Chemoenzymatic synthesis of (3R,4S)- and (3S,4R)-3-methoxy-4-methylaminopyrrolidine

An efficient and a convenient enantioselective synthesis of (3R,4S)-3-methoxy-4-methylaminopyrrolidine has been carried out by a lipase-mediated resolution protocol. This method describes the preparation of (±)-1-Cbz-cis-3-azido-4-hydroxypyrrolidine starting from commercially available diallylamine followed by ring-closing metathesis (RCM) via S_N2 displacement reactions. Pseudomonas cepacia lipase immobilized on diatomaceous earth (Amano PS-D) provides (3R,4S)-11 and (3S,4R)-12 in an excellent enantiomeric excess.     

New chiral spiro[2.5]octanones as products of methylenation of (3<Emphasis Type="Italic">R</Emphasis>, 6<Emphasis Type="Italic">R</Emphasis>)-2-arylidene-6-isopropyl-3-methylcyclohexanones with dimethylsulfoxonium methylide. Synthesis,stereochemistry, and behavior in liquid-crystalline systems

Methylenation of (3R,6R)-2-(4-X-benzylidene)-6-isopropyl-3-methylcyclohexanones (X = F, Cl, Ph) with dimethylsulfoxonium methylide occurs stereoselectively to give 1(S)-(4-X-phenyl)-5(R)-isopropyl-8(R)-methyl-3(R)-spiro[2.5]octanones, whose stereochemistry was established by ¹H NMR spectroscopy. The configuration of the chiral centers in the cyclohexanone fragment and its preferred conformation (methyl is axial and isopropyl is equatorial) in the products do not change with respect to the starting enones. The mutual trans-arrangement of the carbonyl and aryl groups at the newly formed three-membered ring was established; the aryl group also occupies the trans-position with respect to the axial methyl group of the cyclohexanone fragment. Using methylenation of the compound with X = Ph as an example, a mixture of by-products resulting from oxidative hydroxylation at the α-position relative to the carbonyl group was isolated. The resulting chiral spiro[2.5]octanones induce a helical supramolecular ordering in the nematic mesophase of 4-pentyl-4′-cyanobiphenyl and exhibit a twisting power only somewhat (by 20–30%) lower than the starting enones. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2331–2341, October, 2005.     

Radical mediated stereoselective synthesis of (4R,8R)-4,8-dimethyldecanal, an aggregation pheromone of Tribolium flour beetles

(4R,8R)-4,8-Dimethyldecanal, a common aggregation pheromone of Tribolium flour beetles, has been synthesized from (R)-2,3-O-isopropylideneglyceraldehyde in 11 steps and 7% overall yield. The key step in the synthesis is the highly diastereoselective chelation-controlled radical reaction of ethyl (4S,5R)-4-benzyloxy-5,6-(isopropylidenedioxy)-2-methylenehexanoate with ethyl (R)-5-iodo-3-methylpentanoate performed in the presence of 7 equiv of MgBr₂·OEt₂.     

Regioselectivity of the interaction of (1<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with some symmetrical ketones

The interaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with a series of symmetrical ketones has been studied. As a result isomeric oxazolidines are formed in a ratio of 85:15. These oxazolidines were shown to decompose readily under the action of hydrazine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1518–1523, October, 2004.     

Biotransformation of (+)-(1R,2S)-fenchol by the larvae of common cutworm (Spodoptera litura)

Biotransformation of (+)-(1R,2S)-fenchol by the larvae of Spodoptera litura was carried out. Substrate was converted to three new terpenoids, (+)-(1R,2S)-10-hydroxyfenchol, (+)-(1R,2R,3S)-8-hydroxyfenchol and (−)-(1S,2S,6S)-6-exo-hydroxyfenchol, and one known terpenoid, (−)-(1R,2R,3R)-9-hydroxyfenchol. These structures were established by NMR, IR, specific rotation and mass spectral studies.     

Markierte Vertreter eines möglichen Zwischenprodukts der Biosynthese von Fosfomycin inStreptomyces fradiae: Darstellung von (R,S)-(2-Hydroxypropyl)-, (R,S)-, (R)-, (S)-(2-Hydroxy-[1,1-2H2]propyl)-und (R,S)-(2-[18O]Hydroxypropyl)phosphonsäure

Summary Racemic methyl O-benzyllactate was reduced to the alcohol, transformed into the bromide and reacted with triethylphosphite to give the diethylphosphonate. Removal of protecting groups afforded a phosphonic acid which was purified as its cyclohexylammonium salt. (S)-Ethyl and (R)-isobutyl O-benzyllactate were reduced with LiAlD₄ to the corresponding dideuteriated alcohols, which were transformed in the same way as the racemic compound into the chiral (2-hydroxy-[1,1-²H₂]propyl)phosphonic acids. The optical purity of alcohols (S)- and (R)-6 b was determined by derivatisation with (+)-MTPA-Cl and¹H-NMR-spectroscopy to be 98%. Exchange of the carbonyl-16-oxygen atom of 2-oxopropylphosphonate for oxygen-18 from H₂ ¹⁸O, reduction with NaBH₄, deprotection and addition of cyclohexylamine yielded the salt (±)-18 of (2-[¹⁸O]hydroxypropyl)phosphonic acid.