(p-Fluoro-DL-(phenyl-d4)alanine)

P-Fluoro-DL-(phenyl-d4)alanine, also known as FDPPA, is a synthetic amino acid derivative that is widely used in pharmaceutical research. It is a non-natural amino acid analog of phenylalanine, which has been deuterated at the phenyl ring and has a fluorine atom attached to the para position of the phenyl ring. This chemical compound is used as a molecular probe in positron emission tomography (PET) imaging studies of the brain, especially in research related to the dopamine and serotonin neurotransmitter systems. FDPPA is able to selectively bind to the dopamine and serotonin transporters, which are proteins responsible for reuptake of these neurotransmitters from the synaptic cleft back into the presynaptic neuron. By labeling FDPPA with a radioisotope, such as carbon-11 or fluorine-18, researchers can study the distribution and density of dopamine and serotonin transporters in the brain, which can provide insight into neurological disorders such as Parkinson's disease and depression. FDPPA has a molecular formula of C9H7D4FNO2 and a molecular weight of 197.21 g/mol. The deuterium substitution at the phenyl ring of the amino acid allows for easy differentiation from endogenous phenylalanine in biological systems. The fluorine atom at the para position of the phenyl ring enhances the binding affinity of the compound to the dopamine and serotonin transporters.