Pyrazine derivatives: a patent review (June 2012 - present).

INTRODUCTION: Pyrazine is a member of 1,4-diazines, which constitute an important class of heterocycles. Various pyrazine derivatives have been synthesized and successfully evaluated as agents with diverse pharmacological effects (including but not limited to antiproliferative, anti-infective, and effects on cardiovascular or nervous system) and some of them have become clinically used drugs worldwide. AREA COVERED: This review is a survey of important patents on pyrazine derivatives with pharmacological activity published in the period June 2012 - July 2014. The patent databases SciFinder and esp@cenet were used to locate patent applications. EXPERT OPINION: Pyrazine derivatives possess numerous noteworthy pharmacological effects, including antimycobacterial, antibacterial, antifungal, antidiabetic, diuretic, anticancer, antiviral, hypnotic, and analgesic. The class of pyrazine-based candidate drugs has experienced a rapid growth both in absolute numbers of investigated compounds and in the spectrum of diverse biological activities. We expect that several of these compounds will add to existing pharmaceuticals in the very near future. According to the number of compounds and filed patents, the most promising areas are: i) inhibitors of protein kinases (applicable as antiproliferatives); and ii) inhibitors of β-secretase (applicable for the treatment of Alzheimer's disease).