Recent Progress in the Chemistry of Pyridazinones for Functional Group Transformations

Abstract

While N-hetereocycles have received significant attention in organic synthesis and other research fields, the chemistry of pyridazine, a six-membered aromatic ring with two adjacent nitrogen atoms, and its derivatives has been relatively little understood. This Synopsis describes recent progress made in the synthesis of pyridazine derivatives-particularly, pyridazin-3(2H)-ones-and their utility as efficient and recyclable functional group carriers for various important organic reactions.

Transition‐metal‐free Cyclization of Mucohalic Acids with Sulfonyl Hydrazides: An Approach to Pyridazin‐3(2H)‐ones

“…In addition, using 3 a as a model compound, the further transformations of the products 3 and 4 were also explored. As the previously reported studies, [48,49] the bromine atom in 3 a can be substituted by pyrrolidine, giving compound 5 a (Scheme 6). Similarly, morpholine also can react with 3 a to produce compound 5 b via nucleophilic substitution.…”

Synthesis of Pyridazin‐3(2H)‐one Derivatives by the Reaction of CH‐Acids with Dichlorodiazadienes

“…Pyridazine is an important structural unit of many current drugs and agrochemicals (Figure ) . Numerous reviews on pyridazine chemistry have appeared over the past decades to demonstrate growing interest to this type of heterocycles . Pyridazin‐3(2 H )‐ones are one of the most important subtypes of this heterocyclic family highly attractive in modern drug discovery.…”

Construction of 6‐Aminopyridazine Derivatives by the Reaction of Malononitrile with Dichloro‐Substituted Diazadienes

“…Pyridazine derivatives are rarely found in nature, however high attractiveness of this heterocyclic core is constantly growing due to the use of a large number of pyridazine derived drugs and agrochemicals (Figure ). Over the past decades, a large number of reviews in this area appeared to confirm rising interest in pyridazines . Aminopyridazines are widely used for the synthesis of condensed nitrogen‐heterocycles .…”