t
‐Butyl diazoacetate
intermediate:
p
‐toluenesulfonyl azide
solvent: 75.8 g. (0.75 mole) of previously distilled triethylamine
intermediate: 92.6 (0.50 mole) of
t
‐butyl α‐diazoacetoacetate
byproduct:
p
‐toluenesulfonamide
product:
t
‐butyl diazoacetate
Proton-active substances react with certain electron-rich olefins with cleavage of the central C=C double bond to give compounds that can be formally regarded as insertion products of nucleophilic carbenes. If they satisfy certain structural conditions, they isomerize with p elimination to give open-chain compounds. Both CH-acidic compounds and compounds containing NH or OH groups can undergo this reaction. The mechanisms are discussed, and the importance of the intermediate products to biochemistry (thiamine, tetrahydrofolic acid) is indicated.
Reactions of Bis-[l,3-diaryl-imidazolidinyEidenes-(2)1 with Iso-, Isothio-or Isoselenocyanates1)Bis-[1,3-diaryl-imidazolidinylidenes-(2)] (la-c) react with isocyanates in a ratio of 1 : 4 to give 2,4-dioxo-1,3,6,9-tetraaza-spiro[4,4]nonanes (3a-i). As shown in the case of 3f and g, acyl-azides may also be used for this reaction because they rearrange to isocyanates under the reaction conditions; 2-acylimino-l,3-diphenyl-imidazolidines (6a and b) are formed then as byproducts. The reaction of the electron-rich olefine l a with aryl-azides leads to the triazenes l l a or b without loss of nitrogen. Isothio-or isoselenocyanates also undergo a 4 : 1-reaction with l a to give the spiroheterocycles 13a-j. A dipole intermediate 16 could be isolated from 1 a and p-nitrophenyl isocyanate. Analogous 2 : 1-reactions (21 a and b) are found with carbamoyl-isothiocyanates.
Electrochemical cells with polyacetylene, (CH)x, as active anode and cathode material have been built. The cells were of the type (CH)x/R4N+ClO4⊖/(CH)x. The cells with different electrode thicknesses and areas, respectively, showed all the same typical charging and discharging behaviour. From the experimental data the change of molar doping concentration during charge and discharge, charge capacity, energy – and power density are evaluated. – The cell performance is limited by internal losses and electrochemically induced irreversible processes, which also limit the rechargeability to a few cycles.
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