Reduction of 8-, 4-, and 2-quinolinecarboxylic acids with nickel-aluminum alloy (Raney alloy) in 10% NaOH gave 1, 2, 3, 4-tetrahydroquinoline-8-,-4-, and-2-carboxylic acids, which were converted into their ethyl esters [12] by boiling with ethanol in the presence of sulfuric acid and hydrogen peroxide, as described in [16]. The ethyl esters, on boiling with hydrazine hydrate in absolute ethanol, were converted into 1, 2, 3, 4-tetrahydroquinoline-8-,-4-, and- ...
