Bicyclo CompoundsBicyclo Compounds, Heterocyclic: A class of saturated compounds consisting of two rings only, having two or more atoms in common, containing at least one hetero atom, and that take the name of an open chain hydrocarbon containing the same total number of atoms. (From Riguady et al., Nomenclature of Organic Chemistry, 1979, p31)Octanes: Eight-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.ImidesCyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Indole Alkaloids: Group of alkaloids containing a benzylpyrrole group (derived from TRYPTOPHAN)Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Cycloaddition Reaction: Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Adenosine A3 Receptor Agonists: Drugs that selectively bind to and activate ADENOSINE A3 RECEPTORS.Adenosine A3 Receptor Antagonists: Compounds that selectively bind to and block the activation of ADENOSINE A3 RECEPTORS.Prenylation: Attachment of isoprenoids (TERPENES) to other compounds, especially PROTEINS and FLAVONOIDS.Methyl n-Butyl Ketone: An industrial solvent which causes nervous system degeneration. MBK is an acronym often used to refer to it.NorbornanesRhodium: Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)Cyclooctanes: A group of compounds with an 8-carbon ring. They may be saturated or unsaturated.Anti-Anxiety Agents: Agents that alleviate ANXIETY, tension, and ANXIETY DISORDERS, promote sedation, and have a calming effect without affecting clarity of consciousness or neurologic conditions. ADRENERGIC BETA-ANTAGONISTS are commonly used in the symptomatic treatment of anxiety but are not included here.Receptor, Adenosine A3: A subtype of ADENOSINE RECEPTOR that is found expressed in a variety of locations including the BRAIN and endocrine tissues. The receptor is generally considered to be coupled to the GI, INHIBITORY G-PROTEIN which causes down regulation of CYCLIC AMP.KetonesNucleosides: Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)CyclopropanesHexanes: Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Spectrophotometry, Infrared: Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)BornanesMolecular Conformation: The characteristic three-dimensional shape of a molecule.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Sulfur Compounds: Inorganic or organic compounds that contain sulfur as an integral part of the molecule.