JEE MainChemistryGeneral Organic Chemistry
The correct IUPAC name of the compound given by the condensed formula CH ₃ CH ( OCH ₃) C ( Br )= C ( CH ₃) COCH ₂ CHO is
Options
- A3 -bromo- 2 -methoxy- 4 -methyl- 5 -oxohept- 3 -en- 7 -al
- B5 -bromo- 6 -methoxy- 4 -methyl- 1 -oxohept- 4 -en- 3 -one
- C5 -bromo- 6 -methoxy- 4 -methyl- 3 -oxohept- 4 -enal
- D6 -methoxy- 5 -bromo- 4 -methyl- 3 -oxohept- 4 -enal
Correct answer
C. 5 -bromo- 6 -methoxy- 4 -methyl- 3 -oxohept- 4 -enal
Step-by-step solution
The given condensed formula can be expanded to its structural formula as: CH ₃- CH ( OCH ₃)- C ( Br )= C ( CH ₃)- C (= O )- CH ₂- CHO According to IUPAC nomenclature rules: 1. The principal functional group is the aldehyde ( - CHO ), which has higher priority than the ketone ( > C = O ). Thus, the parent chain must be numbered starting from the aldehyde carbon to give it the lowest possible locant ( 1 ). 2. Numbering the longest carbon chain from right to left gives a 7 -carbon chain (heptane derivative). 3. The su