Structure elucidation and synthesis of (2s)-4-oxo-1-azabicyclo[3.3.0]octa-5,7-diehe-2-carboxylic acid,a new metabolite isolated ercm stheptomyces oliyacbjs

The structure of a new metabolite isolated from $\text{Streptomyces}$$\text{olivaceus}$ has been shown to be (2S)-4-oxo-1-azabicyclo[3.3.0]octa-5,7-diene-2-carboxylic acid by means of its spectroscopic properties and total synthesis.     

Structure d'un nouvel heteroside d'isoflavone: le sarothamnoside

The structure of sarothamnoside (genistein 7,4′-di-O-[4-O-β-D-glucopyranosyl-β-D-apiofuranoside]), a new isoflavone glycoside from $\text{Sarothamnus scoparius}$ and $\text{S}$, patens, has been established by spectral analysis, mainly ₁₃C NMR.     

Condensed cyclic and bridged-ring systems : part 12: A novel synthetic route to 4-p-methoxyphenyl-bicyclo[ 2.2.2 ]octan-2-ones and some bicyclo [ 3.2.1 ] octane derivatives by acid-catalyzed intramolecula

The efficacy of a new acid-catalyzed intramolecular C-alkylation has been demonstrated by the synthesis of 1-methyl-4-$\text{p}$-methoxyphenylbicyclo [2.2.2] octan-2-one ($\text{5}$) and 4-$\text{p}$-methoxyphenylbicyclo [2.2.2] octan-2-one ($\text{6}$) from easily accessible starting materials. The carbinol $\text{20}$, derived from $\text{5}$, undergoes facile rearrangement leading to 1-$\text{p}$-methoxyphenyl-4-methyl bicyclo [3.2.1] oct-3-ene ($\text{22}$), which has been transformed to $\text{endo}$-1-$\text{p}$-methoxyphenyl-4-methylbicyclo [3.2.1] octan-3-one ($\text{25}$).     

Necatorone,an alkaloidal pigment from the gilled toadstool lactarius necator (agaricales)

Necatorone, an alkaloid possessing an unusual 5,10-dihydroxydibenzo [de,h] [1,6] naphthyridin-6-one structure has been isolated from fruit-bodies of the toadstool $\text{Lactarius necator}$.     

Structure of an amino acid analog of the host-specific toxin from helminthosporium carbonum

The structure of an analog to the host-specific plant toxin from $\text{Helminthosporium carbonum}$ has been determined to be cyclo [prolylalanylglycyl-2-amino-8-oxo-9,10-epoxydecanyl], which has a glycine residue in place of the D-alanine residue of the toxin.     

Structure of aszonalenin,a new metabolite of aspergillus zonatus

Aszonalenin ($\text{1}$) has been isolated from $\text{Aspergillus zonatus}$ together with LL-S490β ($\text{2}$) and the structure of $\text{1}$ has been established by spectroscopic evidences and chemical transformation.     

The structure of pacifigorgiol,an ichthyotoxic sesquiterpenoid from the pacific gorgonian coral pacifigorgiacf.adamsii

An ichthyotoxic sesquiterpenoid of unusual structure, pacifigorgiol, has been isolated from the Pacific gorgonian caora $\text{Pacifigorgia}$$\text{adamsii}$. The structure of pacifigorgiol, with relative stereochemistry only, has been defined by a combination of spectral and x-ray crystallographic techniques.     

Sterically crowded cyclohexanes-2 synthesis,structure and dynamics of hexaspiro[2.0.3.0.2.0.3.0.2.0.3.0]heneicosane

The synthesis, structure and dynamics of hexaspiro[2.0.3.0.2.0.3.0.- 2.0.3.0]heneicosane $\text{3}$ are described. $\text{3}$ adopts a chair conformation in the crystal state but prefers a chair-to-twistboat equilibrium in solution. The activation parameters of the chair-to-chair interconversion of $\text{3}$ and the closely related hexaspiro[2.0.2.0.2.0.2.0.2.0.2.0]- octadecane ([6]rotane) $\text{4}$ have been determined by DNMR. Some consequences appertaining to the conformation and dynamics of other fully (cyclo-)alkylated cyclohexanes are discussed.     

Natural polyene pyrones. Synthesis of the 2,6-dioxabicyclo[3.2.1]octane unit of citreoviridinol

The 2,6-dioxabicyclo[3.2.1]octane unit, $\text{viz}$ 10, present in citreoviridinol (1) has been produced in a stereoselective manner by treatment of the epoxide (8) derived from citreoviral (6), $\text{via}$ (7), with $\text{p}$-toluenesulphonic acid.     

Laureepoxide,new bromo ether from the marine red alga Laurencianipponica Yamada

An interesting bromine containing compound, laureepoxide ($\text{1}$), has been isolated from $\text{L}$. $\text{nipponica}$ Yamada (Rhodomelaceae, Rhodophyta) and its structure has been determined by the chemical degradations and spectral properties.     

Inhibitors of Ornithine Carbamoyltransferase from Pseudomonassyringae pv. phaseolicola. st]Revised Structure of Phaseolotoxin

The structure of phaseolotoxin, a toxin produced by cultured $\text{Pseudomonas}$$\text{syringae}$ pv. $\text{phaseolicola}$, the causal agent of halo blight disease in bean plants is revised to 3. The structure of octicidin, isolated from leaves of bean plants infected with pv. $\text{phaseolicola}$. has been determined to be 4, a protease degradation product of 3 which is formed in the plant.     

Sedum alkaloids II: sedacryptine, a new minor base from sedum acre.

The structure of sedacryptine $\text{1}$, a new minor alkaloid isolated from $\text{Sedum}$$\text{acre}$, has been established by single-crystal X-ray crystallography.     

Conversion of adenosine to a pentacyclic structure by a 4-nitroquinoline-1-oxide metabolite model.

A new pentacyclic compound $\text{2A}$ has been obtained from the reaction of adenosine $\text{1}$ with 1-acetoxy-4-(acetoxyimino)-1,4-dihydroquinoline $\text{3}$, a model for the ultimate metabolite of the carcinogen 4-nitroquinoline-1-oxide. 9-propyladenine $\text{5}$ gives an analogous pentacyclic product $\text{6A}$ whose crystal structure has been determined.     

Isolation and structure of aaptamine a novel heteroaromatic substance possessing α-blocking activity from the sea sponge Aaptosaaptos

A novel heteroaromatic substance, aaptamine possessing an α-adrenoceptor blocking activity has been isolated from the tropical sea sponge $\text{Aaptos}$$\text{aaptos}$ and its structure has been determined to be $\text{1}$ on the basis of spectral data and chemical degradation.     

X-ray molecular structure of the 1:1 adduct of [FeH(CO)4]− and dimethyl acetylenedicarboxylate. η3-[trans-2,3-bis(methoxycarbonyl)acryloyl]tricarbonylferrate

The crystal structure of a bis(triphenylphosphine)iminium salt of the 1:1 adduct of [FeH(CO)₄]^? and dimethyl acetylenecarboxylate has been determined from three-dimensional X-ray data collected by the counter method. Single crystals belong to the triclinic space space group P$\text{1}$, with two units of [C₃₆H₃₀NP₂]⁺[C₁₀H₇FeO₈]^? in a cell of dimensions: $\text{a}$ = 13.918(2), $\text{b}$ = 15.669(5), $\text{c}$ = 9.909(2) Å, $\text{α}$ = 91.22(3), $\text{β}$ = 94.83(2), and $\text{γ}$ = 77.62(2)°. The structure was refined to a conventional $\text{R}$ of 0.068 for 5373 observed

reflections. The resulting structure indicates that the complex anion is η³-[$\text{trans}$-2,3-bis(methoxycarbonyl)acryloyl]tricarbonylferrate, the coordination around the iron atom being described as a considerably distorted trigonal bipyramid. A comparison of the present structure with the structures of related complexes suggests that the η³-acryloyl portion is best represented as an intermediate of (η³-allyl) with the oxygen atom and (η²-olefin + η¹-acyl). The short Fe-C(acyl) length of 1.897(5) Å implies an enhanced back-donation of electrons from the iron atom to the acyl group.     

Structure of swinholide-a,a new macrolide from the marine sponge theonella swinhoei

Swinholide-A ($\text{1}$a) a novel 22-membered macrolide has been isolated from a Red Sea sponge. The structure of the tetraformate ($\text{1b}$) has been determined on basis of spectral data using 2D-NMR correlations.     

Engleromycin,a new cytochalasan from Engleromycesgoetzei Hennings

The structure of engleromycin isolated from $\text{Engleromyces}$$\text{goetzei}$ Hennings has been established as $\text{1}$ by spectral techniques.     

Laurencianol,a new halogenated diterpenoid from the marne alga laurenciaobtusa

The structure of an anitmicrobial dibromomochloroditerpene alcohol, laurencianol, has been determined by spectral and X-ray crystallographic techniques. The compound has been isolated from the Mediterranean red alga $\text{barLaurencia}$$\text{obtusa}$.     

Ajugareptansin,a new diterpenoid from ajuga reptans (L.)

The structure of a new clerodane diterpene, isolated from $\text{Ajuga}$$\text{reptans}$, has been elucidated by chemical and spectral means and confirmed by X-ray crystallographic studies of the corresponding $\text{p}$-bromobenzoate.     

(4+2)-cycloaddition of nitroalkenes with ynamines; formation of a 4H-1,2-oxazine 2-oxide derivative

The formation of a thermally unstable (4+2)-cycloadduct, a 4H-1,2-oxazine 2-oxide derivative ($\text{1}$), from the reaction of 1-nitrocyclopentene with 1-phenyl-2-(1-pyrrolidinyl)acetylene has been proven by the structure elucidation of isoxazole derivative $\text{3}$ which results from thermal rearrangement and by the structure determination of the 1,3-dipolar adducts $\text{5}$ of $\text{1}$ with electron-deficient acetylenes.