Synthesis and nitration of 7-alkylquinolines

The Skraup synthesis with m-ethylaniline has been shown to give a mixture of 7-ethylquinoline (75%) and 5-ethylquinoline (25%). Pure 7-ethylquinoline has been isolated as a solid. Nitration of 7-methyl- and 7-ethylquinolines gives only the 8-nitro derivatives; the minor products from the nitration of impure samples of 7-alkylquinolines arise from the 5-alkyl- contaminants. 5-Methylquinoline is nitrated at the 6- and 8-positions.