Complex sentence: HNIW is prepared by first condensing benzylamine with glyoxal under acidic and dehydrating conditions, with four of the resulting benzyl groups removed by hydrogenolysis using palladium on carbon and hydrogen and the resulting secondary amine groups are acetylated in acetic anhydride.
Split into simpler sentences: HNIW is prepared by condensing benzylamine with glyoxal under acidic and dehydrating conditions. Benzyl groups are remove by hydrogenolysis using palladium on carbon and hydrogen and the resulting secondary amine groups are acetylated in acetic anhydride.