MECHANISM OF BIOLUMINESCENCE, CHEMI-LUMINESCENCE AND ENZYME FUNCTION IN THE OXIDATION OF FIREFLY LUCIFERIN*,†

Abstract— The chemical steps and the products of the bioluminescent and chemiluminescent oxidations of firefly luciferin are elucidated. The colors of firefly bioluminescence can be explained in terms of different ionic excited states and spectral shifts due to changes in molecular environment. Firefly luciferase undergoes conformational changes during catalysis. There are two sites for light production per 100,000 mW. A regulatory mechanism involving dehydro-luciferin is proposed for control of firefly flashing.     

Immunomagnetic separation of tumor necrosis factor alpha. II. In situ procedure for the human gingival space.

An in situ procedure has been developed for the separation of tumor necrosis factor (TNF) alpha directly from the fluid in the human gingival space. Paramagnetic beads coated with anti-TNF monoclonal antibodies were introduced into the gingival space of the subject with a polypropylene-tipped calibrated delivery system and retrieved using a permanent magnet designed to fit into the space. After retrieval, the amount of immunoadsorbed TNF was quantified using an immunochemical assay called the "cluster assay". The results indicate that following the appropriate preparation of the site, over 95% of the beads could be recovered. With this method we found that 62% of those cavities sampled contained TNF and that the values ranged from 0.10 to 13.0 ng/ml with a mean value of 1.7 ng/ml. A comparison of these values with those obtained from the same space using other methods suggests that the immunomagnetic method was more effective in retrieval of TNF. Because the separation is performed in situ we have named the procedure "chromatobiosis".     

Concerted cycloaddition of chlorosulfonyl isocyanate to α-pinene stepwise rearrangement of the β-lactam cycloadduct to a γ-lactam

Chlorosulfonyl isocyanate adds to α-pinene in concerted fashion to give the unrearranged N-chlorosulfonyl-β-lactam 2 (75%). Thermolysis of cycloadduct 2 affords the rearranged N-chlorosulfonyl-γ-lactam 6 (60%) via a sequence of transient carbonium ions (45). Reductive hydrolysis of 2 and 6 gave, respectively, the NH-β-lactam 3 (70%) and the NH-γ-lactam 7 (70%). Proof of structure of the rearranged γ-lactams 6 and 7 are provided, respectively, by X-ray crystallographic analysis and the application of the Eu(dpm)₃ NMR shift reagent.     

Collision-induced dissociations of substituted benzyl anions: Deprotonated 2-Phenyl-1,3-dithiane

Deprotonated 2-phenyl-1,3-dithiane undergoes competitive losses of H˙, C₃H₆ C₂H₄S, C₃H₄S, C₇H₆S, C₁₀H₁₀ and C₁₀H₁₀S upon collisional activation. The elimination of H occurs from the phenyl ring. The loss of C₃H₆ occurs by simple cleavage of the dithiane ring. All other processes involve specific proton transfer followed by either cleavage or internal nucleophilic displacement.     

The theory and practice of liquid-liquid partition chromatography of phenols

An equation is given for the design of liquid-liquid partition Chromatographie columns which relates the separation factors and column, characteristics with the number of theoretical plates required for a desired separation. This equation should be applicable to the separation of acids or bases when a buffered stationary phase is used, thus permitting a more rational approach to this technique.Using this approach a complete separation of the three isomeric cresols has been achieved. Methods are given for this determination and also for the determination of phenol in tar acid mixtures.     

Dynamic chirality: keen selection in the face of stereochemical diversity in mechanically bonded compounds

The template-directed syntheses, employing bisparaphenylene-[34]crown-10 (BPP34C10), 1,5-dinaphthoparaphenylene-[36]crown-10 (1/5NPPP36C10), and 1,5-dinaphtho-[38]crown-10 (1/5DNP38C10) as templates, of three [2]catenanes, whereby one of the two bipyridinium units in cyclobis(paraquat-p-phenylene) is replaced by a bipicolinium unit, are described. The crude reaction mixtures comprising the [2]catenanes all contain slightly more of the homologous [3]catenanes, wherein a "dimeric" octacationic cyclophane has the crown ether macrocycles encircling the alternating bipyridinium units with the bipicolinium units completely unfettered. X-ray crystallography, performed on all three [2]catenanes and two of the three [3]catenanes reveals co-conformational and stereochemical preferences that are stark and pronounced. Both the [3]catenanes crystallize as mixtures of diastereoisomers on account of the axial chirality associated with the picolinium units in the solid state. Dynamic (1)H NMR spectroscopy is employed to probe in solution the relative energy barriers for rotations by the phenylene and pyridinium rings in the tetracationic cyclophane component of the [2]catenanes. Where there are co-conformational changes that are stereochemically "allowed", crown ether circumrotation and rocking processes are also investigated for the relative rates of their occurrence. The outcome is one whereby the three [2]catenanes containing BPP34C10, 1/5NPPP36C10, and 1/5DNP38C10 exist as one major enantiomeric pair of diastereoisomers amongst two, four, and eight diastereoisomeric pairs of enantiomers, respectively. The diastereoisomerism is a consequence of the presence of axial chirality together with helical and/or planar chirality in the same interlocked molecule. These [2]catenanes constitute a rich reserve of new stereochemical types that might be tapped for their switching and mechanical properties.     

Polymerization by oxidation coupling. I. A study of the oxidation of 2,6-diphenylphenol to poly(2,6-diphenyl-1,4-phenylene ether)

The synthesis of poly(2,6-diphenyl-1,4-phenylene ether), by the oxidative coupling of 2,6-diphenylphenol has been studied. Procedures were found which demonstrated that polymers of very high molecular weight \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\overline M _n > 200{\rm 000; }\left[ \eta \right]_{{\rm CHCl}_{\rm 3} }^{25^\circ {\rm C}} > 1.1{\rm }{{{\rm dl}} \mathord{\left/ {\vphantom {{{\rm dl}} g}} \right. \kern-\nulldelimiterspace} g}} \right) $\end{document} could be made with a copper-amine catalyst system. A low nitrogen-to-copper ratio (1 N atom/Cu atom) was necessary to obtain the very high molecular weights under the conditions of these reactions. A variety of amines formed active catalysts; the effectiveness of mono- and bis- primary, secondary, and tertiary amines were compared. Effects of the type of copper halide, reaction temperature, desiccants, addition rates of 2,6-di-phenylphenol, and solvents were also examined. Samples of polymer were isolated at different times during the polymerization. Measurements of viscosity, osmotic pressure, light scattering, gel permeation, phenolic hydroxyl groups, and nitrogen content were made on various samples over a range of intrinsic viscosities of 0.05–0.59 dl/g. A very narrow molecular weight distribution was found for all samples. Hydroxyl endgroup analyses indicated that the concentration of phenolic endgroups per mole of polymer does not change during the polymerization. The presence of some side reactions is indicated by nitrogen analyses. The relationships between the intrinsic viscosity in chloroform at 25°C and M?_n and M?_w are: log [η] = ?3.97 + 0.72₇ log M?_n and log [n] = ?3.56 + 0.62₄ log M?_w.     

Protonation and methylation of η-2,3,5,6-tetramethyl-1,4-benzoquinone(η-pentamethylcyclopentadienyl)cobalt

The preparation of the η⁴-4-2,3,5,6-tetramethyl-1,4-benzoquinonecomplex [CO(C₅Me₅)(C₁₀H₁₂O₂)] (I) is reported. Complex I undergoesreversible protonation to yield the 2-6-η-4-hydroxy-1-oxo-2,3,5,6-tetramethylcyclohexadienyl complex [Co(C₅Me₅)(C₁₀H₁₃O₂)BF₄ (II) and diprotonation to yield the η⁶-6-1,4-dihydroxy-2,3,5,6-tetramethylbenzene complex [Co(C₅Me₅)(C₁₀H₁₄O₂)] (BF₄)₂ (III). Methylation of complex I with MeI/AgPF₆ gives the 2---6-η-4-methoxy-1-oxo-2,3,5,6-tetramethylcyclohexadienyl complex [Co(C₅Me₅)(C₁₁H₁₅O₂])PF₆ (IV). In trifluoroacetic acid solution complex IV is protonated to form the η⁶-1-hydroxy-4-methoxy-2,3,5,6-tetramethylbenzene cation [Co(C₅Me₅)-(C₁₁H₁₆O₂)]²⁺     

Reactions of poly(phenylene oxide)s with quinones. I. The quinone-coupling reaction between low-molecular-weight poly(2,6-dimethyl-1,4-phenylene oxide) and 3,3′,5,5′-tetramethyl-4,4′-diphenoquinone

A bifunctional polymer is formed when low-molecular-weight poly(2,6-dimethyl-1,4-phenylene oxide) (I) reacts with 3,3′,5,5′-tetramethyl-4,4′-diphenoquinone (II). Infrared (IR), nuclear magnetic resonance (NMR), and gel permeation chromotography (GPC) measurements indicate that the quinone is bound covalently to the polymer chain as a biphenyl moiety which can be located at a terminal position (III, a = 0) or an internal position (III, a > 0): Acetylation of III produces a diacetate ester characterized by field desorption mass spectrometry to confirm the bifunctional nature of III. The reaction of I with II proceeds at 25°C but is faster at elevated temperatures or with amine catalysis. Oxidation of III with oxygen and a copper/amine catalyst of the type used initially to prepare I regenerates II from the biphenyl moiety in III in high yield and converts the remaining oxyphenylene units to high-molecular-weight polymer.     

The Diels—Alder reaction in organometallic chemistry VI. Diels—Alder reactions of α-pyrone with group IV element-substituted acetylenes

The Diels—Alder reactions of α-pyrone with Me₃SiCCSiMe₃, Me₃SiCCSiMe₂H, Me₂HSiCCSiMe₂H, Me₃GeCCGeMe₃, Me₃SiCCGeMe₃, Me₃SiCCSnMe₃ and EtCCEt were examined. All except the first two acetylenes gave the expected 1,2-disubstituted benzene product, in line with results obtained previously with Me₃SnCCSnMe₃. The first two acetylenes, Me₃SiCCSiMe₃ and Me₃SiCCSiMe₂H, also yielded benzene products containing substantial amounts of the 1,3-disubstituted benzenes, as well as minor amounts of the 1,4-isomers. This formation of unexpected isomers during these reactions was shown to result from acid-catalyzed rearrangement of the initially formed 1,2-disubstituted products, 1,2-(Me₃Si)₂C₆H₄ and 1-Me₃Si-2-Me₂HSiC₆H₄. The acidic impurities arose from pyrolysis of the bromobenzene solvent used or were introduced as contaminants of the α-pyrone. Such isomerizations were inhibited by addition of small amounts of triethylamine. The fact that no rearrangement took place with the other acetylenes is due to the scavenging of acidic impurities which might cause isomerization by the starting acetylene and the benzene product via metal—carbon bond cleavage processes.