Synthesis and odor of optically active trans-2,2,6-trimethylcyclohexyl methyl ketones and their related compounds

The synthesis characterized by cationic olefin cyclizations accomplished using ketone enol esters and odor of novel (1R,6S)- and (1S,6R)-2,2,6-trimethylcyclohexyl methyl ketones (5) are described. The stereoselective syntheses of (E)-(1R,6S)- and (E)-(1S,6R)-1-(2,2,6-trimethylcyclohexyl)-2-buten-1-one (6) and (1R,6S)-ethyl 2,2,6-trimethylcyclohexylcarboxylate (7), useful raw materials for flavor and fragrance, starting from the (1R,6S)- and (1S,6R)-5 are also described.     

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.     

New synthesis of serricornin,the sex pheromone of the cigarette beetle (Lasioderma serricorne)

A new approach to the total synthesis of serricornin, the sex pheromone of the cigarette beetle, based on readily available (4S,5E)-4-methyhept-5-enenitrile was implemented.     

Pheromone synthesis. Part 244: Synthesis of the racemate and enantiomers of (11Z,19Z)-CH503 (3-acetoxy-11,19-octacosadien-1-ol), a new sex pheromone of male Drosophila melanogaster to show its (S)-isomer and racemate as bioactive

The enantiomers of (11Z,19Z)-3-acetoxy-11,19-octacosadien-1-ol were synthesized from the enantiomers of 3,4-epoxy-1-butanol PMB ether. Its racemate was also synthesized. Its (S)-isomer and racemate were shown to possess the same pheromone activity as CH503, a long-lived inhibitor of male courtship in Drosophila melanogaster, although the racemate was less active.     

Effects of residual metal compounds and chain-end structure on thermal degradation of poly(3-hydroxybutyric acid)

Thermal degradation behaviours of poly(3-hydroxybutyric acid) (P(3HB); bacterial poly[(R)-3-hydroxybutyric acid] and synthetic poly[(R,S)-3-hydroxybutyric acid] samples, were examined under both isothermal and non-isothermal conditions. The inverse of number-average degree of polymerisation for all P(3HB) samples decreased linearly with degradation time during the initial stage of isothermal degradation at a temperature ranging from 170-190 °C. In addition, crotonyl unit was detected in the residual polymer samples as main ω-chain-end. These results indicate that the dominant thermal degradation reaction for P(3HB) is a random chain scission via cis-elimination reaction of P(3HB) molecules. It was found that the presence of either Ca or Mg ions enhances the depolymerisation of P(3HB) molecules, while that Zn ions hardly catalyse the reaction. As a result, a shift of thermogravimetric curves toward the lower temperature regions was observed for the P(3HB) samples containing high amounts of Ca and Mg compounds.     

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.     

Diarylnonanoids and their glucosides from Erica cinerea

The reinvestigation of Erica cinerea fresh aerial parts led to the isolation of two new diarylnonanoid aglycones along with their glucosides. From spectroscopic data, their structures were elucidated as rel-(3R,7R)-1,9-bis(p-hydroxyphenyl)-3,7-dihydroxynonan-5-one named ericanone, ericanone 3-β-d-glucoside, (3S)-3,7-anhydro-6,7-dehydroericanone and (3S)-3,7-anhydro-6,7-dehydroericanone 4′-β-d-glucoside. Contrary to the numerous diarylheptanoids more frequently distributed in the plant kingdom, the rare diarylnonanoids were previously restricted to the genus Myristica of the Myristicaceae plant family.     

Practical synthesis of (2S,3R)-3-hydroxy-3-methylproline, a constituent of papuamides, using a diastereoselective tandem Michael-aldol reaction

(2S,3R)-3-Hydroxy-3-methylproline, a constituent of cyclodepsipeptides polyoxypeptins A and B, was efficiently synthesized by lithium chloride-induced diastereoselective tandem Michael-aldol reaction using methyl vinyl ketone and N-1-naphthylsulfonylglycine (R)-binaphthyl ester and subsequent hydrolysis of the product in 39% overall yield and five steps.     

Synthesis and Stereochemistry of (1S,3S,4S,7R11R)-3-(4-Nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,04,11]undecane

The reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with glutaraldehyde has been studied. It has been established on the basis of AM1 and PM3 calculations and ¹H NMR spectra recorded in the presence of the shift reagent Eu(fod)₃ that (1S,3S,4S,7R,11R)-3-(4-nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,0^4,11]undecane is formed as the result of the reaction.     

Novel synthesis of (4<Emphasis Type="Italic">R</Emphasis>)-4-methylpentanolide from (L)-(−)-menthol

A novel synthesis of the promising optically pure chiral (4R)-4-methylpentanolide that is based on several regiospecific oxidative transformations of (4R)-2,4-dimethyl-1-(1-methylethyl)-1-cyclohexene, the product of addition of (–)-menthone and methylmagnesium iodide followed by acid dehydration, was proposed.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 451–453, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and characterization of polybinaphthalene incorporating chiral (R) or (S)-1,1′-binaphthalene and oxadiazole units by Heck reaction

Chiral conjugated polymers P-1 and P-2 were synthesized by the polymerization of (R)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthalene ((R)-M-1) and (S)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthalene ((S)-M-1) with 2,5-bis(4-vinylphenyl)-1,3,4-oxadiazole (M-2) under Pd-catalyzed Heck coupling reaction, respectively. Both monomers and polymers were analysed by NMR, MS, FT-IR, UV, DSC-TG, fluorescent spectroscopy, GPC and CD spectra. The chiral conjugated polymers exhibit strong Cotton effect in their circular dichroism (CD) spectra indicating a high rigidity of polymer backbone. CD spectra of polymers P-1 and P-2 are almost identical and have opposite signs for their position. These polymers have strong blue fluorescence.     

Asymmetric Synthesis of （R）- and （S）-Moprolol

A simple and effective procedure for the enantioselective synthesis of （R）- and （S）-moprolol was described. The key step was the asymmetric synthesis of enantiopure （R）- and （S）-guaifenesin, which were synthesized from enantioenriched （R）-3-chloro-l,2-propanediol and （S）-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-Co^Ⅲ complex. The e.e. values of both the optical compounds were above 98%, and the chemical structures of the target compounds were confirmed by ^1H NMR, ^13C NMR, IR, and MS.     

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.     

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.     

Practical optical resolution of dl-muscone using tartaric acid derivatives as a chiral auxiliary

A simple and practical synthesis of (R)-(−)-muscone was achieved by optical resolution of dl-muscone using tartaric acid derivatives. The acetalization of dl-muscone with N,N′-dibenzyl-l-tartaramide in the presence of Sc(OTf)₃ and methyl orthoformate furnished a diastereomeric mixture of acetals, which were readily separated by simple recrystallization. Diastereomerically pure acetal was hydrolyzed to give optically pure muscone and recovered N,N′-dibenzyl-l-tartaramide.     

Stereoselective synthesis of tetrahydroisoquinoline alkaloids: (−)-trolline, (+)-crispin A, (+)-oleracein E

Tetrahydroisoquinoline alkaloids, (S)-(−)-trolline, (R)-(+)-crispin A, and (R)-(+)-oleracein E, have been synthesized stereoselectively from the both enantiomers of common intermediate (S)-4 and (R)-4. The key step in the synthesis include a stereoselective Bi(OTf)₃-catalyzed intramolecular 1,3-chirality transfer reaction of chiral non-racemic amino allylic alcohols (S)-6 and (R)-6 to construct both enantiomers of (E)-1-propenyl tetrahydroisoquinoline 4.     

Platanus acerifolia’s buds: additional non-polar metabolites and structure revision of two previous dihydrochalcone-like metabolites

In addition to the methylated and prenylated flavonoids previously reported from Platanus acerifolia, the multistep chromatographic processing of the n-hexane extract of the fresh unripe buds resulted in the isolation of 11 metabolites. Besides six common wax constituents, the n-hexane portion led to the isolation of four gem-dimethylpyrano flavanones. They corresponded to two pairs of angular and linear isomers derived only from pinocembrin (5,7-dihydroxyflavanone). Additionally, a novel β-decadione was split into the major keto-enol tautomer as shown by the detailed NMR and EIMS analyses. Moreover, the structures of grenoblone and 4-hydroxygrenoblone, two previously reported dihydrochalcone-like metabolites, were revised according to the EIMS spectra.     

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.     

Fungi mediated production and practical purification of (R)-(−)-3-quinuclidinol

A fungal system belonging to Mucoraceae family (Mucor piriformis) was explored for the asymmetric reduction of a prochiral ketone, 3-quinuclidinone (I) in an efficient manner to produce an important pharmaceutical precursor (R)-(−)-3-quinuclidinol (II) with ∼96% enantiomeric excess. The efficiency of the process was improved by developing a cation exchange resin (Amberlite IR-120) which assisted the purification of water soluble metabolite II from fermentation media.     

A novel polyfunctional chiral building block derived from (S)-ethyl lactate. Application to the synthesis of the sex pheromone of the southern corn rootworm (Diabrotica undecimpunctata howardi)

Highly enantiomerically pure (4S, 5E)-4-bromomethylhept-5-enenitrile was prepared from (S)-ethyl lactate by a six-step procedure involving a rearrangement of chiral cyclopropylcarbinol. This product was used for the synthesis of the sex pheromone of the southern corn rootworm (Diabrotica undecimpunctata howardi), (10R)-10-methyltridecan-2-one. For preliminary communication, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 151–155, January, 2000.