Preparation of organic hydrazides
Amiel, Jean-Pierre L.
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Due to the actual high price of hydrazine, this chemical cannot be used in an economical preparation of organic hydrazides. A synthesis of such hydrazides can be envisaged by the reduction of N-nitroamides. The problem is then to find a set of conditions under which no hydrogenolysis of the nitrogen-nitrogen bond occurs. This had been done with N-nitrocarbamates and it was hoped that the results could be extended to N-nitroamides: N-Nitro-N-methylamides were actually used in order to have a more stable N-nitro group. Dimethylation of the hydrazine could be performed either by acid hydrolysis of the addition product obtained with diethyl azodicarboxylate or by heating with pyridinium chloride. After failure to reduce p-N-dinitro-N-methylbenzamide to hydrazine, a new technique was experienced by which the amide was nitrated and reduced directly without isolation of the N-nitroamide. Preliminary results suggested that the electron shifting ability of the R group in molecules of the type R CO-N(NO2)CH3 is very important in their reduction to hydrazine. Several molecules were then reduced with different R. It was found that the yield of hydrazine increases with the electron repelling ability if R. A mechanism involving formation of an unstable platinum hydride is proposed for the reaction. A survery of the addition reactions of azodicarboxylic esters is given with the description of an attempt of "Azo reaction" between diethyl azodicarboxylate and p-N-dinitro-N-methylbenzamide.
Thesis (M.A.)--Boston University