10.1021/jo01200a007
The research investigates the Hofmann-type rearrangement of certain acid amides in liquid ammonia. The primary purpose is to explore the reaction mechanisms and conditions under which specific acid amides, such as 2-phenylquinoline-4-carbonamide, can be converted into amines like 2-phenyl-4-aminoquinoline. potassium amide and potassium nitrate play crucial roles in facilitating the Hofmann-type rearrangement of acid amides in liquid ammonia. Potassium amide, generated in situ from metallic potassium in the presence of an iron oxide catalyst, acts as a strong base and a nucleophile. It is essential for initiating the reaction by deprotonating the acid amide (RCONH2), forming a dipotassium salt (RCONK2). This intermediate is proposed to lose two electrons, either to potassium nitrate or to mercury, to form an isocyanic ester (RNCO). Potassium nitrate, on the other hand, serves as an oxidizing agent, driving the electron transfer process and enhancing the yield of the desired amine products. The presence of potassium nitrate is found to be highly desirable, as it increases the yield of the final amine product from about 40% to 90-98%. The study provides valuable insights into the conditions and mechanisms of these rearrangements, contributing to the understanding of organic reactions in liquid ammonia.
