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.     

[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.     

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.     

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.     

The first x-ray structure determination of a z-phosphaethylene: z-2-phenyl-1-(2,4,6-tri-t-butylphenyl)phosphaethylene

The sterically protected $\text{Z}$-phosphaethylene, $\text{Z}$-2-phenyl-1-(2,4,6-tri-t-butylphenyl)phosphaethylene (1-Z), was analyzed by X-ray crystallography.     

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.     

Stereoselective photosolvolyses of ipso-acetoxynitro-adducts of p-xylene

Diastereoisomers of 1,4-dimethyl-4-nitro-2,5-cyclohexadienyl acetate exchanged acetoxyls for alkoxyls on irradiation in alcohols to give the diastereoisomers of alkyl, 1,4-dimethyl-4-nitro-2,5-cyclohexadienyl ethers in isomer ratios of 70:30, whereas the irradiation in pentane yielded $\text{p}$-xylene.     

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.     

MIRC (Michael Initiated Ring Closure) Reactions Formation of Three,Five, Six and Seven Membered Rings

The term MIRC reaction is defined. Examples of the construction of three, five, six and seven membered rings using alkylthiolates and LDA as nucleophiles are presented.     

The structure of paraherquamide,a toxic metabolite from penicilliumparaherquei

A new toxic metabolite was isolated from $\text{Penicillium}$$\text{paraherquei}$ and the structure was determined by X-ray diffraction analysis. The metabolite was designated as paraherquamide.     

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.     

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).