Question

The structure of spiro \([3,3]\) heptane is \((\mathrm{A})\) C1CC2(C1)CCC2 (B) C1CC12CC2 (C) C1CCC2(C1)CCC2 (D)

Short answer

The correct structural representation of spiro [3,3] heptane using SMILES notations is option (A): C1CC2(C1)CCC2.

Step-by-step solution

Identify the structure of spiro [3,3] heptane

The structure of a spiro [3,3] heptane consists of two "rings" of carbon atoms, each ring having 3 carbon atoms, bonded to each other and sharing a common carbon, thus forming 7 carbon atom structure.

Decipher the first SMILES notation

The SMILES notation of structure A is C1CC2(C1)CCC2. One way to interpret this is to start from the atom 'C1'. The 'C1' moves to 'C', and then to 'C2', making a ring of 3 carbons. Then, from 'C2', it moves to 'C', then to another 'C', and back to 'C2', making another ring of 3 carbons. Hence, option (A) correctly represents spiro [3,3] heptane.

Verify the correctness of the other SMILES notations

To confirm that option (A) is the correct choice, we should also look at the other options: Option (B) - C1CC12CC2: This notation does not form two separate rings of 3 carbon atoms each. So, this does not represent a spiro [3,3] heptane. Option (C) - C1CCC2(C1)CCC2: This structure forms two separate rings, but each ring contains 4 carbons, not 3. Hence, it does not represent a spiro [3,3] heptane. Option (D) - C1CC2(CC1)CC2: This notation also does not form two separate rings of 3 carbon atoms each, hence does not represent a spiro [3,3] heptane. Thus, we conclude that option (A) is the correct representation of spiro [3,3] heptane using SMILES notations.