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.     

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.     

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.     

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.     

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     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

The structures of anhydrobonellin and bonellin,the physiologically active pigment from the marine echiuroid bonelliaviridis

The structure of anhydrobonellin (II) has been proposed by spectroscopic techniques and confirmed by single crystal X-ray diffraction. The relationship of (II) to bonellin is clear and thus the structure of bonellin is certain.