Heterocyclic compound is

Options

A. furan
B. toluene
C. chlorobenzene
D. cyclopropane

Explanation

### Step-by-Step Solution:

1. **Definition of Heterocyclic Compounds**:
- Heterocyclic compounds are cyclic compounds that contain at least one atom in the ring that is not carbon. This atom can be an element such as nitrogen, oxygen, or sulfur.

2. **Understanding Homocyclic vs. Heterocyclic**:
- Homocyclic compounds are those where all the atoms in the ring are the same (typically carbon). In contrast, heterocyclic compounds have different types of atoms in the ring.

3. **Analyzing the Given Compounds**:
- The question provides four compounds: Cypherine, Toluene, Chlorobenzene, and Cyclopropane. We need to determine which of these is a heterocyclic compound.

4. **Identifying Each Compound**:
- **Cypherine**: This is not a commonly recognized compound, but if it contains a heteroatom in a cyclic structure, it could be heterocyclic.
- **Toluene**: This is a derivative of benzene with a methyl group (CH3) attached. It has a six-membered carbon ring (homocyclic).
- **Chlorobenzene**: This is a benzene ring with a chlorine atom attached. It also has a six-membered carbon ring (homocyclic).
- **Cyclopropane**: This is a three-membered carbon ring. It is also homocyclic as it contains only carbon atoms.

5. **Identifying the Heterocyclic Compound**:
- Among the compounds listed, if we consider **Furan** (not listed but mentioned in the video), it is a five-membered ring containing four carbon atoms and one oxygen atom. This makes it a heterocyclic compound.

6. **Conclusion**:
- The only compound that qualifies as a heterocyclic compound from the options provided is **Furan**. The other compounds (Toluene, Chlorobenzene, and Cyclopropane) are all homocyclic.

### Final Answer:
The heterocyclic compound among the options is **Furan**.

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