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810715 min using 345-nm light from the Bausch and Lomb monochromator. Remeasurement of the luminescence spectra showed a decrease in the fluorescence intensity but no phosphorescence.The glass was allowed to thaw and was then refrozen. Use of the phosphoroscope now showed the phosphorescence spectrum of in ethanol. The intensity could not be measured since a clear glass could not be obtained.Photolysis of l a at 77°K. A solution of l a in ethanol was prepared and its fluorescence spectrum measured as described above.Use of the phosphoroscope showed no phosphorescence from the solution. The solution, maintained at 77"K, was irradiated for 2a.12Abstract: 1 -Norbornylamine, 1-apocamphylamine, and 1-adamantylamine have been deaminated using the nitroso-and nitroamide approach. The reaction yields carbonium ions that are reactive enough to abstract chloride ions from solvents such as methylene chloride, probably uia chloronium ion species. The norbornyl ions have a much higher reactivity than the 1-adamantyl ions as shown by the higher ratio of solvent attack to reaction with the negatively charged counterion. Oxygen-1 8 tracer experiments are also reported. The mechanism of deamination is discussed based on these and other results.

A detailed study into the optimization of carbodiimide-mediated coupling of antibodies (Ab) and quantum dots (QD) for use in cellular imaging has been undertaken. This involved the grafting of commercially available carboxyl-modified QDs (Evident Technologies "Lake Placid Blue" Evitag and eBioscience's eflour nanocrystals) with anti-Cdc8 Abs to produce conjugates with specific affinity for fission yeast tropomyosin Cdc8 protein. The water-soluble carbodiimide 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was used to activate the QDs prior to their incubation with antibody, and a range of QD-carboxyl/EDC/Ab mole ratios were used in the experiments in attempts to optimize fluorescence and bioaffinity of the conjugate products (EDC to QD-carboxyl-600 nmol/15 pmol to 0.12 nmol/15 pmol and QD to Ab 120 pmol/24 pmol to 120 pmol/1.2 pmol). It was observed that a specific "optimum" ratio of the three reactants was required to produce the most fluorescent and biologically active product and that it was generated at alkaline pH 10.8. Increasing the ratio of Ab to QD produced conjugate which was less fluorescent while reducing the ratio of EDC to QD in the activation step led to increased fluorescence of product. Conjugates were tested for their possession of antibody by measurement of their absorption at OD(280 nm) and for their fluorescence by assay λ(max(em)) at 495 nm. A quantitative assay of the bioactivity of the conjugates was developed whereby a standardized amount of Cdc8 antigen was spotted onto nylon membranes and reacted with products from conjugation reactions in a sandwich-type colormetric assay The "best" conjugate was used in intracellular imaging of yeast Cdc8 protein and produced brighter, higher definition images of fixed yeast cell actin structure than a fluorescein-Ab conjugate routinely produced in our laboratory. The QD-Ab conjugate was also significantly more resistant to photobleaching than the fluorescein-Ab conjugate. Results from other experiments involving EDC, the water-soluble carbodiimide 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulphonate (CMC), and EDC.HCl have suggested a new reaction mechanism for EDC coupling under basic aqueous conditions. In summary, a robust understanding of commercial QD-COOH surface chemistry and the variables involved in the materials' efficient conjugation with a bioligand using carbidiimide has been obtained along with an optimized approach for Ab-QD conjugate production. A novel assay has been developed for bioassay of QD-Ab conjugates and a new mechanism for EDC coupling under basic aqueous conditions is proposed.

Reduction of 2',4',6'-trimethyl-2-nitrobiphenyl by triethyl phosphite gives 2-amino-2',4 ',6'-trimethylbiphenyl and triethyl N-(2',4',6'-trimethylbiphenyl-2-yl) phosphorimidate. The same reduction, carried out in cumene or in t-butylbenzene gives, additionally, 8,10-dimethylphenanthridine, and, in cumene, 2,3-dimethyl-2,3-diphenylbutane, indicating the intermediacy of a triplet nitrene. Reduction of nitrobenzene by diethyl methylphosphonite in an excess of diethylamine gives 2-diethylamino-3H-azepine (83%). while the corresponding reaction with 2-nitrobiphenyl gives 2-diethylamino-3-phenyl-3H-azepine (1 3%) in addition to carbazole (63%), pointing to an intermediate similar to that present in decompositions of azides, i.e. a nitrene or nitrenoid species, the nature of which is discussed.The order of reducing reactivity of a series of tervalent phosphorus reagents towards 2-nitrobiphenyl is (EtO),PMe S (Et,N),P -(EtO)P(NEt,), > (EtO),P -(PriO),P >>> PCI, (inactive). ScotlandSINCE the discovery of the reaction in 1962,2 the reduction of aromatic nitro-compounds by triethyl phosphite and related reagents has been exploited as a route to a wide variety of nitrogen containing heterocyclic compounds, including carbazoles 293, indoles 29*, indazoles 3, benzotriazoles 3, anthranils 5, phenothiazines 596, quinol-ines ', and related compounds.8 This paper is concerned with aspects of the mechanism of the reduction and, in particular, with the question of the participation of a nitrene, which was postulated as an intermediate at an early stage of the investigation^.^ Evidence for nitrenes is usually taken to be the occurrence of abstraction or insertion reactions with alit Previously communicated in part: J.