How many chiral C - atoms are present in Cimetidine.

Answer

To determine how many chiral carbon atoms are present in cimetidine, we will follow these steps:

### Step 1: Draw the Structure of Cimetidine
First, we need to write down the structural formula of cimetidine. Cimetidine is a compound that contains several functional groups, including nitrogen atoms and a sulfur atom. The structure can be represented as follows:

```
N
|
H2N-C=N-C(=S)-C(CH3)=N
```

### Step 2: Identify Carbon Atoms
Next, we will identify all the carbon atoms in the structure. In cimetidine, we can see that there are several carbon atoms present.

### Step 3: Determine Chirality
Now, we need to check each carbon atom to see if it is chiral. A carbon atom is considered chiral if it is bonded to four different groups or atoms.

1. **Carbon 1**: This carbon is bonded to two nitrogen atoms and has a double bond. It is not chiral.
2. **Carbon 2**: This carbon has three hydrogen atoms attached to it. It is not chiral.
3. **Carbon 3**: This carbon is part of a double bond and is not chiral.
4. **Carbon 4**: This carbon is bonded to two hydrogen atoms, making it not chiral.
5. **Carbon 5**: This carbon is bonded to a nitrogen atom and has a double bond, so it is not chiral.
6. **Carbon 6**: This carbon is bonded to three hydrogen atoms, making it not chiral.

### Step 4: Conclusion
After analyzing all the carbon atoms in cimetidine, we find that none of them are chiral. Therefore, the total number of chiral carbon atoms in cimetidine is **zero**.

### Final Answer
Cimetidine has **0 chiral carbon atoms**.

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