Abstract: Methods and materials for preparing 4-substituted-2-buten-4-olides are disclosed. The method includes reacting a mucohalic acid with a silyl enol ether or a ketene silyl acetal in the presence of a Lewis acid.

Abstract: The invention relates to heterocyclic substituted carbonyl derivatives that display selective binding to dopamine D3 receptors. In another aspect, the invention relates to a method for treating central nervous system disorders associated with the dopamine D3 receptor activity in a patient in need of such treatment comprising administering to the subject a therapeutically effective amount of said compounds for alleviation of such disorder. The central nervous system disorders that may be treated with these compounds include Psychotic Disorders, Substance Dependence, Substance Abuse, Dyskinetic Disorders (e.g. Parkinson's Disease, Parkinsonism, Neuroleptic-Induced Tardive Dyskinesia, Gilles de la Tourette Syndrome and Huntington's Disease), Dementia, Anxiety Disorders, Sleep Disorders, Circadian Rhythm Disorders and Mood Disorders.