A versatile synthesis of functionalised 2-aminoquinolines by mercury controlled cyclisation of 2-vinylphenylthioureas

4-(4-Hydroxyphenyl)-2-phenylamino-1,8-naphthyridine was prepared via cyclisation of N-phenyl-N′-3-(4-hydroxyphenethen-1-yl)pyridin-2-ylthiourea in the presence of mercuric oxide. Derivatives of 4-methyl-2-aminoquinolines were prepared in a similar manner from 2-vinylphenylthioureas.