Volinanserin (; developmental code MDL-100,907) is a highly selective 5-HT<sub>2A</sub> receptor antagonist that is frequently used in scientific research to investigate the function of the 5-HT<sub>2A</sub> receptor. It was also tested in clinical trials as a potential antipsychotic, antidepressant, and treatment for insomnia but was never marketed. The drug reached phase 3 trials for schizophrenia and insomnia prior to the discontinuation of its development in the late 2000s. It is taken orally.
The time to peak levels of volinanserin is 1 to 2.5hours. The elimination half-life of volinanserin is 6.6hours, with a range of 4.5 to 9.8hours. However, cortical serotonin 5-HT<sub>2A</sub> receptor occupancy with volinanserin measured by positron emission tomography (PET) imaging lasts much longer than its circulating elimination half-life would imply.
The synthesis of volinanserin has been reported. Beginning with protection of ethyl isonipecotate (1) with Boc anhydride gives ethyl N-Boc-4-piperidinecarboxylate (2). Ester-amide interchange with N-methoxymethylamine HCl in the presence of carbonyldiimidazole (CDI) coupling agent gives 1-Boc-4-[methoxy(methyl)carbamoyl]piperidine (3). Weinreb ketone synthesis occurs upon benzoylation with 1,2-dimethoxybenzene (4) to give 1-Boc-4-(2,3-dimethoxybenzoyl)piperidine (5). Acid removal of the urethane protecting group gives (2,3-dimethoxyphenyl)-piperidin-4-ylmethanone (6). The reduction of the ketone with sodium borohydride leads to (2,3-dimethoxyphenyl)-piperidin-4-ylmethanol (7). Resolution of the alcohol gives (8). S<sub>N</sub>2 alkylation of the secondary nitrogen with 4-fluorophenethyl bromide (9) completes the synthesis of volinanserin (10).