Question

multiple choice 2 points the synthetic steroid ru-486 is shown below. how many pi bonds does ru-486 contain? image of chemical structure options: 10, 2, 8, 4

Explanation:

Step1: Analyze each functional group

• Benzene ring: A benzene ring (\(C_6H_6\) structure) has 3 double bonds, so 3 pi bonds (each double bond has 1 pi bond).
• Carbon - carbon double bonds: Let's count the \(C = C\) bonds. From the structure, there are 2 \(C = C\) bonds, contributing 2 pi bonds.
• Carbon - oxygen double bond (\(C = O\)): There is 1 \(C = O\) bond, contributing 1 pi bond.
• Carbon - carbon triple bond (\(C\equiv C\)): A triple bond has 2 pi bonds.

Step2: Sum the pi bonds

• Benzene ring: 3 pi bonds.
• \(C = C\) bonds: 2 pi bonds.
• \(C = O\) bond: 1 pi bond.
• \(C\equiv C\) bond: 2 pi bonds.

Total pi bonds \(= 3+2 + 1+2=8\)? Wait, no, wait. Wait, let's re - examine the structure. Wait, the benzene ring: a benzene ring has 3 double bonds (each with 1 pi bond), so 3 pi bonds. Then, the other double bonds: let's see, the structure has a carbon - oxygen double bond (1 pi bond), two carbon - carbon double bonds (2 pi bonds), and a carbon - carbon triple bond (2 pi bonds). Wait, but maybe I miscounted. Wait, the correct way:

Benzene ring: 3 double bonds (3 pi bonds).

\(C = O\): 1 double bond (1 pi bond).

\(C = C\): Let's see the steroid part, maybe 2 \(C = C\) bonds? Wait, no, maybe the correct count is:

Benzene ring: 3 pi bonds.

\(C\equiv C\): 2 pi bonds.

\(C = O\): 1 pi bond.

\(C = C\): 2 pi bonds. Wait, no, maybe the actual structure:

Wait, the correct answer is 10? No, wait, let's do it properly.

A double bond (\(C = C\), \(C = O\)) has 1 pi bond. A triple bond (\(C\equiv C\)) has 2 pi bonds. A benzene ring has 3 double bonds (so 3 pi bonds).

Now, let's identify each:

1. Benzene ring: 3 pi bonds.

1. \(C = O\) (carbonyl group): 1 pi bond.

1. \(C = C\) bonds: Let's say there are 2 \(C = C\) bonds: 2 pi bonds.

1. \(C\equiv C\) bond: 2 pi bonds.

Wait, 3 + 1+2 + 2=8? But the options have 10, 2, 8, 4. Wait, maybe I missed the benzene ring's count. Wait, no, a benzene ring is a conjugated system with 3 double bonds (6 pi electrons, 3 pi bonds). Wait, maybe the structure has two benzene - like rings? Wait, the structure shows a steroid with a benzene ring (phenyl group), and then in the steroid nucleus, maybe some double bonds. Wait, let's re - evaluate:

• Phenyl ring (benzene): 3 pi bonds.

• \(C = O\): 1 pi bond.

• \(C = C\): Let's say 2 \(C = C\) bonds: 2 pi bonds.

• \(C\equiv C\): 2 pi bonds.

Wait, 3+1 + 2+2 = 8. But maybe I made a mistake. Wait, the correct answer is 10? No, wait, maybe the phenyl ring is a six - membered ring with 3 double bonds (3 pi bonds), then another double bond in the steroid, a carbonyl, and a triple bond. Wait, no, let's check the options. The options are 10, 2, 8, 4.

Wait, maybe the correct count is:

Benzene ring: 3 pi bonds.

\(C = O\): 1 pi bond.

\(C = C\): 2 pi bonds (two double bonds).

\(C\equiv C\): 2 pi bonds.

Wait, 3 + 1+2+2 = 8. So the answer should be 8.

Answer:

8 (corresponding to the option with 8)