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The development of functional materials and smart surfaces has received tremendous attention in recent years. The anchoring of molecular machines and the transfer of their properties on to solid substrates may facilitate the design of new smart devices. Herein, we report an approach to the covalent modification of glassy carbon electrodes with electrochemically responsive tris(N-phenylureido)calix[6]arene-based pseudorotaxanes. The main focus of this study has been the electrochemically driven threading/de-threading process of the redox active dialkylviologen axial component of the supramolecular assemble. After the creation of an amine monolayer on the electrode, pseudorotaxane systems were generated at the surface using different approaches. It was revealed, through electrochemical investigations, that the reversibility of the threading/de-threading process of the axle depended on the nature of the alkyl substituents on the axle.

Samarium(II) diiodide mediated intramolecular cyclisation of mixed enone–enoate substrates in THF/MeOH is described. Spirocyclic ethers are obtained, and the stereodefined preparation of 1-oxaspiro[4.4]nonan-7-one products is included.

We report the preparation, using electrochemical and solid-phase synthesis, and characterisation of a 26 member library of 13 dihydroxybenzene derivatives covalently attached to glassy carbon through ethylenediamine (EDA) and C(6)H(4)CH(2)NH linkers. First, Boc-protected EDA or Boc-NHCH(2)C(6)H(4) were electrochemically attached to the GC surface. After Boc-deprotection, dimethoxybenzoyl chlorides were coupled to the EDA and C(6)H(4)CH(2)NH linkers using solid-phase synthesis followed by deprotection of the methoxy groups to give the corresponding dihydroxybenzene compounds. Surface coverage and electrochemical parameters of the dihydroxybenzene modified electrodes were evaluated in parallel using cyclic voltammetry. The mid-peak potentials, E(mp), and surface coverages for the 13 dihydroxybenzene derivatives were found to be independent of the choice of linker. The mid-peak potentials of the immobilised dihydroxybenzene derivatives varied between 0.0 and 260 mV vs. SCE and their surface coverages varied between 0.07 and 1.1 nmol cm(-2), depending on the pattern of substitution of the dihydroxybenzene ring. The electrocatalytic activities of the library were evaluated for mediation of NADH oxidation, and the ortho-dihydroxybenzene derivatives were found to have higher catalytic activity.

Samarium(II) diiodide-mediated intramolecular cyclodimerisation of simple bis-enones and -enoates in THF/MeOH has been investigated. Spirocyclic and elaborated polycyclic products, including stereodefined cis-bicyclo[3.3.0]octane and trans-bicyclo[4.3.0]nonanes, are obtained in synthetically useful yield.

Two dialkylated isocyanides were first synthesised from simple starting materials and then used as building blocks for the synthesis of indolizidines via a novel radical cyclisation/N-alkylation/ring closing metathesis strategy. Several functionalised indolizidines were accessed in good to excellent yields.

Different extracts of Caesalpinia mimosoides Lamk. (Leguminosae) were tested against eight human pathogenic bacteria and six fungal strains by the disc diffusion method. Among these extracts, the aqueous and the ethanolic extracts showed potent activity against some tested microorganisms. Subsequently, the latter extract was fractionated by means of Sephadex LH-20 column chromatography. A bioactive substance, responsible for the antimicrobial property was separated, and its structure was assigned as a known compound, gallic acid, by extensive chromatographic and spectroscopic analyses.

A library of diamidopyridine derived tweezer receptors with peptidic side-arms has been prepared. Screening experiments with the library and a dye-labelled tripeptide l -Glu– l -Ser– l -Val–OH showed excellent selectivity (strong binding of the dye-labelled guest to ∼0.2% of resin-bound library members was observed) and led to the identification of a tweezer receptor structure, which was shown to bind the tripeptide with good selectivity over related tripeptide sequences. Analogous screening experiments with the side-chain protected tripeptide l -Glu(OtBu)– l -Ser(tBu)– l -Val–OH, showed little selectivity for any particular library member. The results are discussed in relation to previous screening experiments, using the same tripeptide guests, with related tweezer receptor libraries, which differ by one methylene in the separation of the diamidopyridine unit from the peptidic side-arms of the tweezer receptors.

Radical cascade cyclisation of methylenecyclopropyl cyclohexanone adducts, using samarium diiodide to generate an initial ketyl radical, provide a short route to tricyclic ethers, and the stereochemical outcome can be influenced by the solvent used for the reaction.

Addition of lithium bis(methylenecyclopropyl)cuprates to acetoxy azetidinones gives methylenecyclopropyl azetidinones, which can be converted to various radical cyclisation precursors. Attempted 4-exo cyclisation of 3 led only to reduced product, while cyclisation of 5, using CuCl/bipy, gave a carbacephem, via a 5-exo cyclisation, but in low yield. Cyclisation of 6 and 7, however, gave novel tricyclic β-lactams, as the result of 7-endo cyclisation, in good yield, and a cyclisation of bromide 23 led to the tricyclic β-lactam 24, via a radical cascade sequence.

Two new receptors, 9 and 13, have been prepared, utilising a pyridyl aryl ether unit in the rim of the macrobicyclic structure, and the crystal structures for both of these receptors are reported. The presence of the pyridyl unit provides additional hydrogen bonding functionality in comparison to earlier structures of this type, and 9 is an effective receptor for N-acetyl L-asparagine carboxylate in CH2Cl2.

A novel cascade sequence, that begins with the samarium(II) iodide mediated formation of a ketyl radical, leads to a primary alkyl radical, which appears to be partially ‘protected’ from the anticipated further reduction to an organosamarium, and instead undergoes a highly stereoselective dimerisation.

The Lewis acid mediated cyclisation of various methylenecyclopropyl ketones, ketals and aldehydes has been investigated as a new route to six- and seven-membered rings. Cyclisation of aldehyde 6, ketal 9 and ketone 11 with TiCl4 gave cyclohexene products, and cyclisation of ketal 10 gave a dichlorocycloheptene, all via nucleophilic addition of the methylenecyclopropyl π bond to the activated carbonyl. Cyclisation of ketone 12, however, with SnCl4, gave a cyclopentanol 21, presumably via nucleophilic addition of a cyclopropyl σ bond to the activated carbonyl.

1,2 Disubstituted methylenecyclopropyl bromides, 6 and 11, undergo radical cascade reactions, involving cyclisation, ring-opening and further cyclisation, to give cis bicyclic products in 67% and 41% yields respectively.

Macrocyclic receptor 9 , has been prepared in homochiral form. The receptor shows selectivity for certain dipeptides, and most notably a strong preference for N -Cbz-β-alanyl amino acids over N -Cbz-β-alanyl lactic acids.

An appropriately functionalised guanidine has been connected to a solid support, allowing peptide chains to be attached by conventional solid phase synthesis. This provides the basis for the solid-phase synthesis of libraries of ‘tweezer’ receptors for peptides with a carboxylate terminus.

Three novel polymer-supported isocyanides have been synthesised, from commercial Wang and HMBA-AM resins, and reacted under radical conditions with 2-mercaptoethanol and ethanethiol to give the corresponding pyrrolidine or pyroglutamic acid derivatives in good yields.

6-exo Cyclisations of methylenecyclopropyl ketones, mediated by samarium diiodide, have been investigated with a series of substrates. The efficiency of the cyclisations are highly dependent on the stereochemistry of the cyclisation precursor.

A novel macrobicycle featuring an amidopyridine unit as a carboxylic acid binding site, and amide functionality to provide further hydrogen bonding interactions with suitable guests has been prepared. The ability of this novel macrobicycle to bind peptide derivatives has been investigated.

The radical cyclisations of methylenecyclopropane derivatives 8, 11, 12, 14 and 16 have been studied, and provide a route to spirocyclic systems.

Alkenyl and alkynyl isocyanides were synthesised and then reacted, using microwave flash-heating technology, with thiophenol, 2-mercaptoethanol and ethanethiol, in the presence of a radical initiator, to give highly functionalised pyrrolines and pyroglutamates. Direct comparison with results obtained using traditional heating techniques showed the advantage of using the microwave technology in terms of faster reactions and better yields.

Lewis acid-mediated intermolecular addition of silylated methylenecyclopropane to aldehydes provides a novel route to tetrahydrofuran derivatives.

Radicals derived from methylenecyclopropane derivatives 8,9 and 17 underwent a sequence of radical cyclisations and fragmentation to give tricyclic products.

Cyclisations of various methylenecyclopropyl substituted malonate radicals have been studied. Radicals derived from malonates 4 and 9 underwent exclusive 5-exo cyclisation onto the methylenecyclopropane alkene, followed by opening of the resulting cyclopropylmethyl radical, to give methylenecyclohexane products. Radicals derived from malonates 5 and 10 largely gave bicyclo[1.5.0]octane products, in good yields, as a result of 7-endo cyclisation. Cyclisation of the radical derived from malonate 11 gave a bicyclo[1.5.0]nonane derivative in 31% yield, as a result of an 8-endo cyclisation.

Samarium diiodide mediated cyclisation of methylenecyclopropyl ketones, readily prepared from β-ketoesters provides a simple route to bicyclo-[3.2.1]-octanes.

The new multi-sulphur donor ligand ortho-xylenedithiodithiolate (OXDT-DT) has been prepared. Monoanionic complexes of OXDT-DT with Ni(ii), Cu(ii) and Au(iii) have been isolated as the (C4H9)4N salts. The monoanions are readily oxidised to the neutral metal complex by treatment with iodine or by electrochemical oxidation.

Addition of lithium bis(methylenecyclopropyl) cuprate to alpha,beta -unsaturated ketones provides an efficient route to methylenecyclopropyl ketones which on treatment with TiCl4 give a range of cyclised products.

The p -acetoxybenzylthio protecting group has been found to be compatible with the triethylphosphite mediated cross-coupling of 4,5-dialkylthio-1,3-dithiol-2-ones, providing access to the tetrathiolate 5 , and to dithiolates 11a and 11b , which are excellent precursors for unsymmetrical tetrahioalkyl tetrathiafulvalene derivatives.

Tandem radical cyclisation of bromide (8b) led to bicyclic ketone (13), an intermediate in the synthesis of isoiridomyrmecin (14), demonstrating that highly stereoselective tandem cyclisations from acyclic precursors can be achieved if the precursor is suitably substituted.

Novel bis - and tris -tetrathiafulvalene (TTF) amphiphiles have been prepared by coupling together TTF monoamines or with TTF mono and diacids. This synthetic route provides a more efficient route to bis - and tris -TTF amphiphiles than that previously described.

A novel macrocycle featuring a crown ether ring, amide functionality and a rigid biaryl unit has been prepared as a potential receptor for small peptidic guests. The synthesis of the macrocycle includes a palladium catalysed biaryl formation as the ring-closing step.