showing 11 related works from this author
Stereochemistry of terpene derivatives. Part 7: Novel rigidified amino acids from (+)-3-carene designed as chiral GABA analogues
2010
Abstract Several novel cyclopropyl-rigidified γ- and δ-amino acids 3 – 4 have been prepared starting from monoterpene (+)-3-carene 2 . These compounds are proposed as chiral analogues of γ-aminobutyric acid (GABA) 1 and are expected to be of interest as potential inhibitors of GABA receptors.
Synthesis and analysis of activity of a potential anti-melanoma prodrug with a hydrazine linker
2013
A potential anti-melanoma prodrug containing a phenolic activator, a hydrazine linker, and a nitrogen mustard effector - (N-{4-[bis-(2-chloroethyl)amino]benzoyl}-N'-(4-hydroxybenzyl)hydrazine) has been synthesized in seven steps. Spectrophotometric measurements of its oxidation by tyrosinase showed a rapid increase of absorbance at 337 nm. HPLC analysis demonstrated that two major products were formed. However, during the reaction one of the products was converted into the other. The stable product with a maximum of absorption at 337 nm was isolated and identified as 5,6-dihydroxy-1H-indazol-1-yl 4-[bis-(2-chloroethyl)amino]benzoate. It was formed by a cyclization of the enzymatically gener…
Synthesis of disparlure and monachalure enantiomers from 2,3-butanediacetals
2020
2,3-Butanediacetal derivatives were used for the stereoselective synthesis of unsymmetrically substituted cis-epoxides. The procedure was applied for the preparation of both enantiomers of disparlure and monachalure, the components of the sex pheromones of the gypsy moth (Lymantria dispar) and the nun moth (Lymantria monacha) using methyl (2S,3R,5R,6R)-3-ethylsulfanylcarbonyl-5,6-dimethoxy-5,6-dimethyl-1,4-dioxane-2-carboxylate as the starting material.
Selective isomerization of a trans -butanediacetal derivative of tartaric acid with differentiating substituents at C-2 and C-3
2017
Abstract A trans-disubstituted butanediacetal derivative with two different substituents (ester and thioester) – methyl (2R,3R,5R,6R)-3-ethylsulfanylcarbonyl-5,6-dimethoxy-5,6-dimethyl-1,4-dioxane-2-carboxylate, was selectively converted to the cis derivative – methyl (2S,3R,5R,6R)-3-ethylsulfanylcarbonyl-5,6-dimethoxy-5,6-dimethyl-1,4-dioxane-2-carboxylate in high yield on a multigram scale. The product of this reaction offers the possibility for selective modification of one of the substituents, which was demonstrated by Fukuyama reduction of the thioester group.
Stereoselective reactions of a thioester butanediacetal with various electrophiles
2014
Abstract The reactions of the lithium enolate of S -ethyl (2 R ,5 R ,6 R )-5,6-dimethoxy-5,6-dimethyl-[1,4]-dioxane-2-carbothioate were investigated in the presence or absence of hexamethylphosphoramide (HMPA). Fluorination gave a single isomer with a much better yield than for the corresponding methyl ester. Alkylation with alkyl halides strongly depended upon their structure. Without HMPA, only methyl iodide reacted with moderate yield and gave a single isomer. In the presence of HMPA, all of the alkyl halides reacted almost quantitatively (81–98% yield) with moderate stereoselectivity and preferentially gave products with the alkyl chain attached at the equatorial position. The silyl eno…
Stereochemistry of terpene derivatives. Part 4:☆ Fragrant terpenoid derivatives with an unsaturated gem-dimethylbicyclo[3.1.0]hexane system
2005
Abstract Starting from (+)-3-carene 1 several chiral fragrant compounds with the bicyclo[3.1.0]hexane system 4–6 and 10–20 were synthesized. These compounds are structural analogues of naturally occurring fragrant compounds, such as ionones and damascones, and possess either an endo- or an exo-cyclic double bond in the bicyclo[3.1.0]hexane moiety. The absolute configuration of selected products was confirmed by X-ray crystallography and circular dichroism analysis.
Synthesis of the aggregation pheromone of the Colorado potato beetle from its degradation product
2015
Incubation of the Colorado potato beetle aggregation pheromone, (S)-1,3-dihydroxy-3,7-dimethyl-6-octen-2-one, with antennal or leg extracts from this beetle gave 6-methyl-5-hepten-2-one as the major product. This ketone was used as a substrate in a stereoselective synthesis of the pheromone. It was attached to the butanediacetal of glycolic acid with good stereoselectivity and the desired isomer was further enriched by purification of the product of this reaction on silica gel.
Lactones. Part 15: Synthesis of chiral spirolactones with a carane system—insect feeding deterrents
2002
Abstract Starting from (+)-3-carene 1 several spirolactones with carane backbone were synthesized. δ-Hydroxy-γ-lactone 5 was obtained by acidic lactonization of a γ,δ-epoxy ester. Iodolactone 8 and bromolactone 9 were products of iodolactonization of γ,δ-unsaturated acid 7 and bromolactonization of γ,δ-unsaturated ester 3 respectively. The halo lactones were subjected to reductive dehalogenation with tributyltin hydride and dehydrohalogenation with DBU. The structures of the lactones obtained were confirmed by X-ray analysis and spectral data.
Stereochemistry of terpene derivatives. Part 3: Hydrolytic kinetic resolution as a convenient approach to chiral aminohydroxyiminocaranes with local …
2002
Abstract We have developed a stereoselective hydrolytic kinetic resolution process for diastereoisomeric mixtures of epoxyiminocarene intermediates in the presence of ( R , R )-(−)-(salen)Co(III)OAc catalyst, this was applied as the first step in the synthesis of novel chiral aminohydroxyiminocarane derivatives with local anaesthetic activity. The absolute configuration of the product was confirmed by X-ray crystallography.
Synthesis and stereochemistry of some new derivatives of cis-dihydropinol
1999
Abstract The synthesis of four new derivatives of cis-hydroxy-cis-dihydropinol with allyl-, epoxyalkyl-, hydroxyalkyl- and ketoalkyl-groups substituted on the cyclohexane ring is presented. The cis-orientation of hydroxyl group at C-2 and the configuration of all stereogenic centers is confirmed by X-ray crystallography.
Stereochemistry of terpene derivatives. Part 5: Synthesis of chiral lactones fused to a carane system—insect feeding deterrents
2006
Abstract Chiral iodo- 9, bromo- 10 and hydroxylactones 12 condensed with the carane system were obtained. In each case, the synthetic pathway led to an enantiomerically pure diastereoisomer to generate two stereogenic centers. Iodo- 9 and bromolactone 10 possess a γ-lactone group while the hydroxylactone 12 possesses a δ-lactone moiety situated trans to the gem-dimethylcyclopropyl ring. The structures of the products were confirmed by X-ray crystallography. These lactones were tested for antifeedant activity against storage pest insects.