Acylhydrazone derivatives: a patent review

The N-acylhydrazone (NAH) moiety has been characterized as a privileged structure, capable of providing ligands points for more than one type of bioreceptor. Modifications of the subunits bonded to its acyl and imine functions resulted in several derivatives, which modulate a great diversity of molecular targets. In this context, this patent review reflects the use of the NAH moiety in different compounds.

In this review, the authors perform an analysis of the therapeutic profile of NAH compounds together with their perspective of its usability. The Espacenet and Delphion databases were used as main sources of search, and 'N-acylhydrazone,', 'Acylhydrazone' and 'hydrazone' were used as keywords. From a total of 117 patents retrieved, 22 presented pharmacological activities described in the document, thus being chosen for this review.

In the last century, only six patents disclosing NAH derivatives for therapeutic purposes were published, and only in 2010, this subunit started receiving some real attention regarding its therapeutic potential. In this review, the Brazilian and Chinese Universities were identified as the major patent applicants, especially for drug candidates for the treatment of chronic pain, inflammatory disorders and cancer. The NAH subunit is very versatile both from synthetic and medicinal chemistry point of view. This feature is a direct result from the conformational diversity that this framework presents, achievable by subtle and simple chemical changes. Therefore, our opinion is that this moiety suits a lot more drug discovery projects than it seems to at first glance. In conclusion, we strongly support and encourage a raise in the use of this unique subunit.