Subject hydrogen iodide

It is probable that the actual mechanism of the decomposition is unimolecular, but, the observed order of the reaction being zero, we cannot tell whether the molecules decompose singly or by interaction with their neighbours. The catalytic decomposition of hydrogen iodide on the surface of platinum can actually be shown to be unimolecular. The heat of activation in this instance is even lower (14,000 cals.), but is again subject to the same uncertainty as the values for the unimolecular reactions of nitrous oxide. 

The concentration of hydrogen iodide in the reaction product is almost insensitive on pressure until 11 bar, but is subject to a parallel dependence above 11-11.5 bar Figure 9). 

L-dihydroxy-succinic acid (L(dexiro)-tartaric acid, CXIII). This result establishes the position of the double bond between C4 and C5 and demonstrates that C4 carries only one hydrogen atom while C5 has attached to it the enolic hydroxyl group. Treatment of the enol CXI with ethereal diazomethane gives 5-methyl-A4-D-glucosaccharo-3,6-lactone methyl ester (CXIY) which upon further methylation with silver oxide and methyl iodide yields 2,5-dimethyl-A4-D-glucosaccharo-3,6-lactone methyl ester (CXV). When the latter is subjected to ozonolysis there is formed oxalic acid and 3-methyl-L-threuronic acid (CXVI). Oxidation of this aldehydic acid (CXYI) with bromine gives rise to a monomethyl derivative (CXVII) of L-ilireo-dihydroxy-succinic acid. 

Any species dissolved in the water is clearly going to be subject to chemical reaction with these ultrasonically produced radicals and/or hydrogen peroxide. Thus if iodide ion is present in solution iodine will be liberated. Spin trapping ESR techniques afforded positive identification of the radical species sonically generated in water [40]. 

One of the earliest reported preparations of the requisite glycosidation precursor 5-deoxy-l,2,3-tri-0-acetyl-p-D-ribofuranoside (17) was published by Kissman and Baker in 1957.23 D-Ribose was heated at reflux in a methanol/acetone mixture in the presence of concentrated HCI to provide methyl 2,3-O-isopropylidene-D-ribofuranosidc (21), which was in turn converted to the corresponding 5-O-mesyl ribofuranoside 22 with methanesulfonyl chloride in pyridine in 63% yield. The sulfonate moiety of 22 was then displaced with sodium iodide in refluxing DMF to provide 5-deoxy-5-iodo derivative 23 in 76% yield on a multigram scale. Reductive dehalogenation of 23 was accomplished under heterogeneous catalytic hydrogenation conditions to provide the reduced 2,3-0-protected intermediate 24 in 56% yield, which was subjected to hydrolysis conditions in... 

The idea of the chemical laser is nearly as old as the whole area of experimental laser physics. The first meeting on the subject, in 1963 32>, was organized by the American Optical Society, and chemical laser emission was reported for the first time in 1965 by Kasper and Pimentel 33>. The emission occurred in the photolytically initiated hydrogen-chlorine explosion (H2/CI2 ->-2 HC1). Predating this discovery, the first photodissociation laser was described by the same authors in 1964 84>. This laser was based on the formation of excited iodine in the photochemical dissociation of alkyl iodides, preferentially trifluoromethyl iodide. 

When 1 is subjected to the carboxylate anion of 3 (TEA, R1CO2H), 2-acyloxy-l-methylpyridinium iodide (2) is formed. The hydrogen halide (HC1) is scavenged with triethylamine. A nucleophile (NuH) (4) such as an amine or alcohol in the presence of TEA adds to the carbonyl center of 2, yielding the desired product 5 and the by-product, l-methyl-2-pyridone (6). 

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