Summary Flow Charts -- Organic Nitrogen Compound Chemistry

The chapter's closing flow-chart page ties together the preparation and reaction webs built section by section. PREPARATION OF R-NO2 AND R-O-N=O: nitrobenzene is reached by reduction of the aniline/nitro cycle; from alkyl halides, R-X + AgNO2 gives predominantly R-NO2 (nitroalkane, major) with R-O-N=O (nitrite, minor), while R-X + KNO2 instead gives predominantly the nitrite (major) with the nitroalkane as the minor product -- the metal nitrite's counter-ion controls which product dominates. NITROBENZENE'S REDUCTION LADDER is redrawn as a single branching map: Sn/HCl (acid medium) to aniline; Zn/NH4Cl (neutral) to phenylhydroxylamine; alkaline-medium self-condensation (Na3AsO3/NaOH) to azoxybenzene, further reduced (Zn/NaOH/CH3OH or LiAlH4) to azobenzene, and again (Zn/NaOH) to hydrazobenzene; and electrolytic reduction branching by acidity into aniline (weakly acidic) or p-aminophenol via phenylhydroxylamine rearrangement (strongly acidic). NITRATION maps alkanes (ethane + HNO3 gives a nitroethane/nitromethane mixture) alongside arenes (benzene + HNO3/H2SO4 gives nitrobenzene via the nitronium electrophile). CHEMICAL PROPERTIES OF NITROALKANES close the loop: hydrolysis (primary to acid, secondary to ketone + N2O), halogenation (nitromethane + Cl2/NaOH to chloropicrin), and n …