The structures of amino-acid conjugates of bonellin derived from the marine echuroid bonelliaviridis

A series of compounds in which amino-acids are conjugated to the C-17c carbonyl group of bonellin have been obtained from the body wall of $\text{Bonellia}$$\text{viridis}$.     

Advanced sedex (sensitive detector of exothermic processes)

The instrument described is suitable for the investigation of the thermal behaviour of substances and reaction mixtures under production conformable conditions; this is made possible by the sophisticated design of the sample chamber: easy stirring of the samples, measuring under any gas atmosphere and while bubbling gas through the sample, choice of the sample container and visual observation during the measurement. The control device allows the choice of one of three operational modes: constant temperature, linear increase in temperature, and adiabatic control; this permits the application of the SEDEX apparatus for a variety of methods including dynamic scanning, isoperibolic measurements, and (quasi) adiabatic studies.     

Spirostane derivatives highly oxygenated at A and B rings from the rhizomes of rohdeajaponica roth and of campylandra aurantiaca baker

Two steroidal compounds BR-1 (I) and ?2 (II) which had been obtained from the rhizomes of $\text{Campylandra aurantiaca}$ Baker, were isolated also from those of $\text{Rohdea japonica}$ Roth. They were identified, respectively, by X-ray analysis and chemical correlation as 1β,2β,3β,4β,5β,7α-hydroxy-spirost-25(27)-en-6-one and its corresponding 6β-hydroxy compound.     

The ipso-nitration of p-cresol

The nitration of $\text{p}$-cresol by nitric acid in aqueous sulphuric acid involves ~40% $\text{ipso}$-substitution at C^Me. The 4-methyl-4-nitrocyclohexa-2,5-dien-1-one (I) formed undergoes an acid-catalysed rearrangement to 4-methyl-2-nitrophenol.     

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.     

Balearone,a metabolite of the brown alga cystoseirabalearica

The isolation of a new metabolite of mixed biogenesis, balearone $\text{1}$from the brown alga $\text{Cystoscira}$$\text{balearica}$ is described. The structure was determined by an X-ray diffraction analysis.     

Solvolytic behavior of p-dimethylamino-α-bromostyrene in water solutions

Nmr and UV studies show that $\text{p}$-dimethylamino-$\text{α}$-bromostyrene, I, undergoes S_Nl reaction in H₂O and HClO₄ (^kS_Nl = 6 × 10^?1sec.^?1 at 25°). The vinyl cation has an extraordinary selectivity for capture by aromatic amines relative to H₂O, including I itself to give the dimer II.     

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.     

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).     

Synthesis of N-benzoyl-L-daunosamine from D-threonine

The synthesis of N-benzoyl-$\text{L}$-daunosamine (14) from the C₄$\text{threo}$ aldehyde (2b), prepared from $\text{D}$-threonine, through the intermediacy of the C₇ adduct (7a) is reported     

Steroidal antifeedants from the dorid nudibranch Aldisasanguineacooperi

Two steroids, 3-oxo-chol-4-ene-24-oic acid ($\text{2}$) andi ts unsaturated analog $\text{4}$ have been isolated from the dorid nudibranch $\text{Aldisa}$$\text{sanguinea}$$\text{cooperi}$, and the acid $\text{2}$ has been shown to have antifeedant properties.     

Reappraisal of the structure for the alkaloid buddamin from buddleyadavidii

The structure of the alkaloid buddamin, isolated from $\text{Buddleya}$$\text{davidii}$ cannot be correct, based upon the reported spectral data. An alternate structure is proposed, which also suggests that buddamin is an artifact of the isolation procedure.     

Stereoselective synthesis of 1,8- and 1,5-diketo-trans-syn-trans-perhydroanthracenes

A stereOselective conversion of 1,8- and 1,5-diethoxy-9,10-anthraquinone to 1,8- and 1,5-diketo-$\text{trans}$-$\text{syn}$-$\text{trans}$-perhydroanthracenes by successive sodium borohydride, metal-ammonia, and catalytic reductions is described.     

A new polyether toxin from Gymnodiniumbreve Davis

A new ichthyotoxic toxin was isolated from the unialgal culture of the deleterious Florida red tide organism, $\text{Gymnodinium}$$\text{breve}$ Davis (Syn. $\text{Ptychodiscus}$$\text{brevis}$), and its structure was elucidated.     

Empirical determination of medium effects on the equilibrium between transcis and transtrans 1,2-dibromo-4-t-butylcyclohexanes

Head space analysis, GLC retention time data, and solution calorimetry are used to determine the effect of medium on the thermodynamic parameters for the equilibrium (1) ? (2). It is shown that changes in ΔG° and ΔH° can be evaluated for the transfer of the equilibrium from a series of solvents to the gaseous phase which is used as the reference medium.     

Behavior of p-dimethylamino-α-bormostyrene and its dimer in dioxane-water

Monomeric $\text{p}$-dimethylamino-$\text{α}$-bromostyrene undergoes S_Nl increasingly slowly in 60 to 91% dioxane. Reaction is catalyzed by HClO₄, NaOH and NaClO₄. Dimer 11 reverts to monomer I in 91% dioxane. There is only a small solvent effect on the solvolysis rate of II.     

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.     

Preparation of halo-F-methanes via potassium fluoride-halogen cleavage of halo-F-methylphosphonium salts

Treatment of halo-$\text{F}$-methylphosphonium salts with potassium fluoride and halogen (I₂, Br₂, ICl, IBr) gives modest yields of halo-$\text{F}$-methanes. This method of preparation augments the classical Hunsdiecker approach to these materials.     

A new class of macrocyclic diterpenes from Bertyadimerostigma (euphorbiaceae)

Three diterpene acids, representing a new class of bicyclic diterpenes, have been isolated from $\text{Bertya dimerostigma}$ F. Muell. (Euphorbiaceae). Spectroscopic and X-ray cryatallographic evidence for their structure is presented. A rationale for their origin $\text{via}$ modification of the casbane skeleton is given.     

Lemnalol,a new sesquiterpenoid from the soft coral Lemnaliatenuis Verseveldt

The structure and absolute stereochemistry of lemnalol (1), a new ylangene-type sesquiterpenoid isolated from the soft coral $\text{Lemnalia}$$\text{tenuis}$ Verseveldt, has been established by spectroscopic, chemical, and x-ray crystallographic analyses.