8-(3-chlorostyryl)caffeine

**8-(3-chlorostyryl)caffeine** (CSC, 8-CSC) is a synthetic compound derived from caffeine, used primarily in research settings. It is a potent and selective antagonist of the **adenosine A2A receptor** (Ki = 54 nM) with much lower affinity for adenosine A1, A2B, and A3 receptors (Ki values 28,000 nM, 8,200 nM, and >10,000 nM, respectively)[3][1][9][5]. Additionally, it is a potent, competitive **monoamine oxidase B (MAO-B) inhibitor** (Ki ~100 nM for rat, 80.6 nM for baboon MAO-B)[3][1][9]. The compound is neuroprotective in preclinical models of Parkinson's disease and can reverse certain dopamine antagonist-induced motor effects[3][1]. It was one of the first selective adenosine A2A antagonists to be developed and is mainly used in neuroscience research; it is not approved for human therapeutic use.

Other names

3-chlorostyrylcaffeine(E)-8-(3-chlorostyryl)-1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione(E)-8-[2-(3-chlorophenyl)ethenyl]-1,3,7-trimethyl-1H-purine-2,6-dione