Subject lead—oxygen bonds

A rather more complex tertracyclic indole based compound lowers blood pressure by selective blockade of a 1-adrenergic receptors. Reaction of the anion from indole (72-1) with butyrolactone (72-2) leads to the scission of the carbon-oxygen bond in the reagent and the formation of the alkylated product (72-3). The acid is then cyclized onto the adjacent 2 position to give the ketone (72-4) by treatment with a Lewis acid such as polyphosphoric acid. Reaction with bromine then leads to the brominated ketone (72-5). This is subjected to reductive alkylation with ethylene... 

If alkenes or alkynes are subjected to strain, their jt bonds are weakened, and such compounds often behave chemically as diradicals. Their tendency to dimerize or polymerize will be significantly enhanced, and quick reaction with oxygen will occur in air [18, 19]. Reactions of strained alkenes which lead to a decline of strain, for example Michael additions or cycloadditions, can proceed significantly faster than with related, unstrained alkenes (Scheme 3.6). 

Alpha-lead azide crystals, wrapped in a thin aluminum foil, were subjected to fast and thermal neutrons in a heavy-water reactor [53]. With a thermal flux rate of about 10 n/cm /sec, the crystals were irradiated for 8, 17, and 170 hr. The crystals decomposed to a brown powder, which was identified as lead carbonate by X-ray diffraction and infrared absorption. From a mass spectrographic analysis of the isotopes of carbon and oxygen in the decomposition products, it was determined that the carbonate was formed fiom the atmosphere by the breaking of surface bonds by the neutrons. It was subsequently reported [54] that the total dose required for conversion to lead carbonate is approximately 7.5 X 10 n/cm ... 

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