Herpepentol,nouveau lignoide pentamere isole d'Herpetospermum caudigerum wall.

The title compound, a new pentamer of coniferyl alcohol has been isolated from seeds of $\text{Herpetospermum caudigerum}$ Wall. (Cucurbitaceae). Its structure was established by spectroscopic means as 4,9,9′,9″,9″′,4″″-hexahydroxy-5,5′,5″,5″′,5″″-pentamethoxy-7.0.4′,8.3′,7′.0.4″,8′.3″,7″.0.4 8″.3″′,7″′.0.9″″,8″8′.″″--lignoid.     

Herpetetradione,nouveau lignoide tetramere isole d'Herpetospermum caudigerum wall.

The title compound, a new tetramer of coniferyl alcohol, has been isolated from seeds of $\text{Herpetospermum caudigerum}$ Wall. (Cucurbitaceae). Its structure was elucidated by spectroscopic means as $\text{rel}$-(7′S, 8′S, 7″S, 8″)-4,9,4′,4″,4″′,9″′-hexahydroxy-5,5′5″,5″′-tetramethoxy-7,7″′-dioxo-8.3′, 7′.0.9″,8′.8″,9′.0.7″,3″.8″′ -lignoïd.     

Stereocontrolled (E,Z and erythro, threo) synthesis of ⊙-hydroxyallylic sulphides

All four isomers of substituted 3-alkylthio-4-hydroxybutenes have been synthesised: both the geometry of the double bond and the relative stereochemistry of the two chiral centres are controlled.     

Diastereoselective synthesis of N-acetyl-D,L-acosamine and N-benzoyl-D,L-ristosamine

N-Acyl derivatives of $\text{D}$,$\text{L}$-acosamine and $\text{D}$,$\text{L}$-ristosamine were synthesized with high stereo selectivity utilizing intramolecular Michael addition of γ- and δ-carbomoyloxy-α,β-unsaturated esters.     

[2+2] Cycloaddition of benzyne to cis,trans- and cis,cis-1,5-cyclooctadiene

The relative rates of formation of $\text{cis}$ and $\text{trans}$ [2+2]cycloadducts of benzyne to $\text{cis}$, $\text{trans}$- and $\text{cis}$, $\text{cis}$-1,5-cyclooctadiene, $\text{trans}$- and $\text{cis}$-cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described.     

Die Schwingungsspektren der isomeren Komplexe N,N′-Bis(dimethylgallium)-cis- und trans-N,N′-dimethyloxamideine kritische Analyse

Reaction of Ga(CH₃)₃ with N,N′-dimethyloxamide affords two isomeric N,N′-bis(dimethylgallium)-N,N′-dimethyloxamide complexes, characterized by crystal structure analysis as having cis-and trans-configuration with respect to the central oxamide CC bond and belonging to the point groups C_2v (cis) and C_2h (trans), respectively. Both isomers which are formed in varying ratio, depending upon the reaction conditions, have been isolated in pure form; their vibration spectra (IR/RE) are analyzed in detail in points of alternative behaviour, and are assigned in all bands, especially in the G-C and Ga-X frequency region. The assignment receives further confirmation from a comparison with the vibrational data of the homologous N,N′-bis(dimethylgallium)oxamide (cis/trans isomer mixture).     

New highly oxidized fusicoccane diterpenoids from the liverwort plagiochilaacanthophylla subsp. japonica

Four novel fusicoccane diterpenoids, fusicoplagins A, B, C, and D, have been isolated from the liverwort $\text{Plagiochila}$$\text{acanthophylla}$ subsp. $\text{japonica}$ and the structures determined by spectroscopic methods, chemical transformations, and X-ray crystallographic analysis.     

Autorecycling oxidation of alcohol catalyzed by 1,3,7,9,11,12,14-heptazapentacene-2,4,8,10 (14H,3H,9H,12H)-tetraones (mixed flavins)

1,3,7,9,11,12,14-Heptazapentacene-2,4,8,10 (14$\text{H}$,3$\text{H}$,9$\text{H}$,12$\text{H}$)-tetraones (mixed flavins) were prepared by the cyclization of 1,5-dihydro-8-[N-alkyl-N-(5-nitrouracil-6-yl)-amino-5-deazaflavins with Vilsmeier reagent. The mixed flavins oxidized alcohol under neutral condition in sunlight and a remarkable autorecycling was observed.     

Boat-chair conformational preference of exo, exo-9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid

The ¹H and ¹³C nmr spectra of $\text{exo}$, $\text{exo}$-9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d₆ or alkaline D₂O, clearly show that it exists in a $\text{boat}$-$\text{chair}$-conformation with $\text{equatorial}$ carboxyl groups, thus being the first case of $\text{boat}$-$\text{chair}$ preference of a bicyclo[3.3.1] nonan-9-one due to the presence of $\text{exo}$,$\text{exo}$-2,4- substituents.     

Synthesis of Lobesia botrana and Spodoptera littoralis natural sex-attractants

Starting from the coupling reaction of alkyl cuprates with 1-alkynyl-2-propenyl acetates, the title compounds were prepared by short convenient syntheses.     

Methods for stereospecific synthesis of cis or trans hydrindanones

Methods are described for the stereospecific conversion of hydrindenone 3 either to the corresponding $\text{trans}$ fused or $\text{cis}$ fused hydrindanone (1 or 2, respectively.)     

Synthesis of the enantiomeric forms of cis and trans 1-benzyloxy-2,3-epoxy butane and of (3S,4S) 4-methyl-3-heptanol

The C₄erythro and threo diols (7) and (8) are converted either into the chiral epoxides (13) and (15) or into the enantiomers (14) and (16); the epoxide (13) is used as chiral synthon for the preparation of (3$\text{S}$,4$\text{S}$) 4-methyl-3-heptanol (21).