Cyclohexylamine when treated with nitrous acid yields (P). On treating (P) with PCC results in (Q). When ( Q ) is heated with dil. NaOH we get ( R ) The final product (R) is :
(A)(see structure)
(B)(see structure)✓ Correct
(C)(see structure)
(D)(see structure)
Answer: (B)
Solution
Cyclohexylamine treated with nitrous acid loses nitrogen through a diazonium intermediate to give cyclohexanol, which is the product P. Oxidation of this secondary alcohol with pyridinium chlorochromate stops at the ketone, giving cyclohexanone as Q. Warm dilute alkali then drives the self aldol reaction of cyclohexanone, and elimination of water from the beta-hydroxy ketone places the new double bond between the alpha carbon of one ring and the former carbonyl carbon of the other, in conjugation with the surviving carbonyl. The final product R is 2-cyclohexylidenecyclohexan-1-one.
JEE Main · 2023 · 31 Jan 2023 · Shift 2 · Single correct option