CC1CC4

CC1CC4 is a fragment of the SMILES notation used to encode chemical structures. As a standalone string, it does not specify a complete molecule because SMILES relies on paired ring closure digits and explicit atomic connectivity.

In SMILES, digits denote the start and end of rings; each digit should appear exactly twice in a valid string. The snippet CC1CC4 shows two ring-closure digits, 1 and 4, each appearing once, which means the rings they mark are not closed within this fragment. To render a valid molecule, the string would need additional atoms and corresponding digits to close the rings at appropriate positions. The specific way these closures are added determines the resulting topological structure, potentially producing bicyclic or more complex polycyclic frameworks.

As an isolated fragment, CC1CC4 has no unique identity or chemical properties. It is primarily of interest as a demonstration of ring-closure syntax in SMILES rather than as a descriptor of a particular compound. In practice, such fragments appear within larger SMILES strings or in discussions of notation syntax, where they help illustrate how ring closures are represented.

Notational notes: In SMILES, uppercase C denotes aliphatic carbon, while lowercase c denotes aromatic carbon. Other elements and symbols (such as parentheses for branching) are used to define the complete connectivity. Without the full string, CC1CC4 cannot be assigned a specific chemical name, formula, or properties.

See also: SMILES notation, ring closure, bicyclic compounds.