A new approach to the synthesis of racemic analogs of 1,5-dimethyl-branched insect pheromones from 4-methyltetrahydropyran

A new procedure was developed for the synthesis of racemic analogs of 1,5-dimethyl-branched insect pheromones based on monoalkylation of ethyl acetoacetate with 1-acetoxy-5-bromo-3-methylpentane produced upon decyclization of 4-methyltetrahydropyran.     

Two isomeric fourteen-membered bis-dithioacetals derived from (<Emphasis Type="Italic">Z</Emphasis>)- and (<Emphasis Type="Italic">E</Emphasis>)-but-2-ene-1,4-dithiols

(Z)-But-2-ene-1,4-dithiol was found to undergo isomerization into the E isomer. Condensation of (Z)- and (E)-but-2-ene-1,4-dithiols with acetaldehyde gave isomeric fourteen-membered bis-dithioacetals whose structure was determined by X-ray analysis.     

Polymers derived from a polyether, 2,4-toluene diisocyanate,and octamethylcyclotetrasiloxane

Russian Journal of Applied Chemistry - Polymers prepared from a polyether, 2,4-toluene diisocyanate, and octamethylcyclotetrasiloxane were studied using thermomechanical analysis, mechanical tests,...     

Stereochemistry of seven-membered heterocycles: XLVII. Synthesis,NMR, XRD,and theoretical investigation of monosulfoxides of (<Emphasis Type="Italic">Z</Emphasis>)-4,7-dihydro-1λ<Superscript>4</Superscript>,3-dithiepine series

By oxidation of (Z)-4,7-dihydro-1,3-dithiepines with meta-chloroperbenzoic acid the corresponding 4,7-dihydro-1λ⁴,3-dithiepine 1-oxides were synthesized in ∼85% yield. A complete assignment of signals in the ¹H and ¹³C NMR spectra of the compounds obtained was established. According to XRD analysis the seven-membered heterocycles crystallized in conformations chair or boat. The calculations by DFT method in the B3LYP/6-31G(d,p) version showed the possibility of conformational equilibrium of these forms in the gas phase.     

UNIVERSAL APPROACH TO THE SYNTHESIS OF JUVENOID HYDROPRENE AND METHOPRENE FROM 4-METHYLTETRAHYDROPYRAN

A universal approach to the synthesis of juvenoid hydroprene and methoprene was developed on the basis of monoalkylation of acetoacetate by 1-acetoxy-5-bromo-3-methylpentane, the product of acidic decyclization of 4-methyltetrahydropyran.     

Synthesis of (4R)-Methylnonan-1-ol and (4R,8RS)-Dimethyldecanal from (S)-(+)-3,7-Dimethyl-1,6-octadiene

Optically active (4R,8RS)-dimethyldecanal, an analog of the aggregation pheromone of the flour beetles Tribolium confusum and T. Castaneum, and (4R)-methylnonan-1-ol, the sex pheromone of the yellow mealworm Tenebrio molitor L., are synthesized using ozonolytic transformation of (6R,10)-dimethyl-9-undecen-2-one to (6R)-methyl-9-hydroxynonan-2-one in the key step. The starting compound is available as enantiomerically enriched (ee ~50%) (S)-(+)-3,7-dimethyl-1,6-octadiene.     

Synthesis of (3S,6RS)- and (3RS,6RS)-Analogs of Component AI of the Aonidiella aurantii Sex Pheromone by Stepwise Alkylation of Acetoacetic Ester

Synthetic approaches to (±)- and (3S)-analogs of the AI component of the Aonidiella aurantii sex pheromone (3S)-methyl-6R-isopropenyldec-9-en-1-ylacetate based on stepwise alkylation of acetoacetic ester by 3-butenylbromide and 1,5-bifunctional 3-methylpentanes were investigated. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 589–591, November–December, 2005.     

Lipids of the wastes from the processing ofAconitum leucostomum

It has been established that the wastes from the production of the drug allapinin from the epigeat pan ofAconitum leucostomum consist of nonpolar and polar lipids with a high content of phospho- and glycolipids and free fatty acids.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 37–40, January–February, 1995.