IUPAC name of the following compound is: CH3 – CH – OCH3 | CH3

Concept

An ether R–O–R′ is named by IUPAC substitutive nomenclature: choose the longest continuous carbon chain as the parent alkane, and name the –O–R′ group attached to it as an 'alkoxy' substituent (methoxy, ethoxy, etc.), using the smaller of the two alkyl groups for this substituent role.

Application

1. Identify the carbon skeleton ignoring the ether oxygen: CH3–CH(CH3)– is a 3-carbon chain (propane), since the branch CH3 attached to the middle carbon extends the count to three carbons total, not two.

2. The –OCH3 group attached to the middle carbon of this propane chain is the smaller alkyl-oxygen unit, so it is named as a methoxy substituent, not as a separate parent chain.

3. Number the propane chain to give the substituent the lowest locant: the methoxy group sits on C2 (the middle carbon), giving the name 2-methoxypropane.

Cross-check / Contrast

• Isopropyl methyl ether names the same molecule by the older functional-class convention (alkyl + alkyl + 'ether'), not by IUPAC substitutive rules — correct compound identification, wrong naming system for what was asked.

• 1-methoxy-1-methyl ethane and 2-methoxy-2-methyl ethane both treat the molecule as a 2-carbon 'ethane' parent with an extra methyl group hung on as a substituent; that undercounts the longest chain — the extra carbon must be counted into the parent chain itself, making it propane, not ethane — so neither locant assignment is a valid IUPAC name.

Hence the IUPAC name of the compound is 2-methoxypropane.