Gattermann reaction chlorination

The interesting research of Votocek, Zenisek 4 and Sebor 5 may also be referred to in this connection. This permits the Sandmeyer-Gattermann reaction (substitution of the diazo-group by chlorine and bromine) to be carried out electrolytically. For this purpose the diazotized solution of the amine is electrolyzed —for instance 50 g. aniline, 120 g. HC1, 38.5 g. NaN02—between copper electrodes with addition of cuprous chloride or copper sulphate. At the end of the experiment (ceasing of the nitrogen... 

Amino groups at the 3-, 4-, 5-, or 6-positions in pyridazine 1-oxides have been successfully replaced by chlorine or bromine in the Gattermann reaction, but yields of 3-chloro (or bromo) derivatives are low. As there are no other suitable methods, this reaction provides the most convenient synthesis of 5- and 6-halo-pyridazine 1-oxides. In this manner 3-, 4-, 5-, and 6-bromopyridazine... 

Preparation of Chlorine Derivatives by the Sandmeyer and Gattermann Reactions ... 

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