Richard A. Russell

Some observations on the chemiluminescent reactions of tris(2,2′-bipyridyl)ruthenium(III) with certain papaver somniferum alkaloids and their derivatives

A series of qualitative tests were performed to evaluate the chemiluminescent activity resulting from the reactions of tris(2,2′-bipyridyl)ruthenium(III) with certain Papaver somniferum alkaloids and their derivatives. The tests were conducted over the range pH 2 to 12 with both emission intensities and lifetimes being qualitatively monitored. The results of this preliminary investigation have revealed an emerging pattern, relating certain aspects of molecular structure (within a family of analogous compounds), to chemiluminescent activity. The presence of phenolic moieties, aromatic or quaternary nitrogens quenched the chemiluminescence. Of potential analytical utility was the facility to manipulate the kinetics of chemiluminescence generation with changes in molecular structure and variation of reaction pH

New and improved ‘LEGO’ BLOCK protocols for the direct synthesis of hydrophilic ribbon molecules with acid, ester or peptide functionality

Abstract Hydrophilic ribbon molecules are produced directly from the reaction of cyclobutene epoxide BLOCKs with norbornene dipolarophiles or indirectly by chemical modification of substituents in preformed lipophilic ribbon molecules. The formation of di- and tetra-acid chloride epoxides holds the key to the formation of ester, acid and amide BLOCKs which are active in 1,3-dipolar cycloadditions with norbornene dipolarophiles, thereby delivering a wide range of substituents into the ribbon molecules and opening up combinatorial opportunities at each step.

Oxidations of substituted phenols with hypervalent iodine : Applications to the phthalide annulation route to anthraquinones

Abstract Substituted phenols are oxidized by phenyliodonium diacetate in methanol to yield either cyclohexa-2,4- or the isomeric 2,5-dienones depending upon the structure of the phenol. Annulation of these oxidation products with the anion of 3-cyanophthalide affords access to a range of anthraquinones not previously accessible by this route.

Oxidation with hypervalent iodine reagents. Part II: Novel cyclohexadienones as precursors for the synthesis of anthraquinones

Abstract The oxidation of substituted phenols with phenyliodonium diacetate in methanol was found to afford 2,4-cyclohexadienones, 2,5-cyclohexadienones or mixtures of isomers, depending on the substrate being oxidized. Annulation of these cyclohexadienones with the anion of 3-cyanophthalide afforded anthraquinones in high yields.

syn-Facial hetero-bridged [n]polynorbornanes: a new class of polarofacial framework molecules composed of fused 7-oxa- and 7-azanorbornanes

Abstract New oxygen-bridged norbornane-fused cyclobutene epoxides and bis-(cyclobutene epoxides) are described and shown to react stereoselectively with 7-azanorbornenes to produce syn-facial N,O-bridged polynorbornanes and stereorandomly with 7-oxanorbornenes to produce O,O-bridged polynorbornanes as mixtures of syn-facial and anti-facial products. 1 Polarofacial systems containing up to six syn-facial norbornane bridges are described, while systems with seven co-facial oxygen atoms have been prepared by incorporating terminal epoxide rings to O5-[5]polynorbornanes. Ester-substituted 1,3,4-oxadiazoles are shown to be useful reagents for coupling 7-oxanorbornanes and produce predominantly syn-facial O-bridged polarofacial systems together with their anti-facial isomers.

Molecular topology: The synthesis of a new class of rigid arc-shaped spacer molecules based on syn-facially fused norbornanes and 7-heteronorbornanes in which heterobridges are used to govern backbone curvature

Abstract Norbornadienes and 7-heteronorbornadienes are reacted with 7-oxa (or carba or aza) norbornene-fused cyclobutene epoxides (or aziridines) to produce hetero-bridged polynorbornane cycloadducts containing syn -facially arranged N,O (or C,N or C,O) bridges. New dual cyclobutene epoxides and dual cyclobutene aziridines are used to prepare multi-fused norbornanes having curved topology in which the heteroatoms modify the curvature in a predictable way C>N>O; AM1 modelling of representative [9]polynorbornanes is prosented.

The synthesis of U-shaped cavity molecules with “inner-surface” functionality

Abstract New U-shaped cavity molecules with inner-surface functionalisation, eg 19 and 20 , have been prepared by stereoselective reaction of cyclopentadiene onto linear bis -(7-oxanorbornenes) 18 and 17 respectively. The norbornene π-centres of cavity molecules 19, 20 are reacted with DMAD/Ru to yield rigid bis -cyclobutenes 21 and 22 which serve as a common entry point to advanced cavity systems with further inner-surface functionalisation (CO, O, alkene). This is achieved by reaction of 21 or 22 with appropriate cyclic dienes (cyclopentadienones, isobenzofurans, furan and 6,6-dimethylfulvene) in highly specific cycloaddition reactions.

Studies on the mechanism of the peroxyoxalate chemiluminescence reaction: Part 2. Further identification of intermediates using 2D EXSY 13C nuclear magnetic resonance spectroscopy

Further consideration has been given to the reaction pathway of a model peroxyoxalate chemiluminescence system. Again utilising doubly labelled oxalyl chloride and anhydrous hydrogen peroxide, 2D EXSY (13)C nuclear magnetic resonance (NMR) spectroscopy experiments allowed for the characterisation of unknown products and key intermediate species on the dark side of the peroxyoxalate chemiluminescence reaction. Exchange spectroscopy afforded elucidation of a scheme comprised of two distinct mechanistic pathways, one of which contributes to chemiluminescence. (13)C NMR experiments carried out at varied reagent molar ratios demonstrated that excess amounts of hydrogen peroxide favoured formation of 1,2-dioxetanedione: the intermediate that, upon thermolysis, has been long thought to interact with a fluorophore to produce light.

Incorporation of a molecular hinge into molecular tweezers by using tandem cycloadditions onto 5,6-dimethylenenorbornene.

Site-selective 1,3-dipolar coupling at the norbornene pi-bond of 5,6-dimethylenenorbornene 1 yields cycloadducts with an end-fused 1,3-diene system which have been reacted with N=N (or C=C) dienophiles to produce ribbon molecules, in which the internal diazacyclohexene (or cyclohexene) subunits are capable of acting as conformational hinges. Direct coupling of 5,6-dimethylenenorbornene with 1,3,4-oxadiazoles or dual coupling with bis(cyclobutene epoxides) afforded bis(1,3-dienes) that diastereoselectively react with dienophiles to produce new, conformationally mobile, molecular tweezers.

A caveat regarding chiroptical measurements of chiral anthracyclinones

Abstract The specific rotations of anthracyclinones are shown to exhibit dramatic variation induced by protic solvents. The significance of this finding to the evaluation of optical purity of synthetic anthracyclinones is discussed.