Compound A with molecular formula C 8 H 8 reacts rapidly with KMnO 4 to give CO 2 and a carboxylic acid, B (C 7 H 6 O 2 ). When treated with H 2 /Pd it absorbs only one molar equivalent of H 2 but under conditions that reduce aromatic rings it takes up four equivalents of hydrogen to produce a hydrocarbon, (C 8 H 16 ). Structures of A, B and C are to be given and the reactions are to be written. Concept introduction: The addition of hydrogen to double bonds in alkene takes place readily in the presence of metals like Pd, Pt, Ni etc. The double bonds in aromatic rings require stronger conditions for adding hydrogens. When oxidized with aqueous acidic KMnO 4 , the double bond in alkene is cleaved to yield carbonyl compounds as products. A disubstituted carbon in double bond is oxidized to a ketone while a monosubstituted carbon in double bond is oxidized to a carboxyl group. If the carbon in double bond contains two hydrogens it will be oxidized to CO 2 . To give: The structures of the compounds A, B and C and to explain the reactions.

Question

An unknown hydrocarbon A with the formula C6H12 reacts with 1 molar equivalent of H2 over a palladium catalyst to give hydrocarbon B. Hydrocarbon A also reacts with OsO4 to give the glycol C. When oxidized with KMnO4 in acidic solution, A gives two fragments. One fragment is propanoic acid, CH3CH2COOH, and the other fragment is ketone D (R2C=O). What are the structures of A, B, C and D? Write all reactions.

Answer 1

Question

Chapter 8.SE, Problem 65AP

Interpretation Introduction

Interpretation:

Compound A with molecular formula C₈H₈ reacts rapidly with KMnO₄ to give CO₂ and a carboxylic acid, B (C₇H₆O₂). When treated with H₂/Pd it absorbs only one molar equivalent of H₂ but under conditions that reduce aromatic rings it takes up four equivalents of hydrogen to produce a hydrocarbon, (C₈H₁₆). Structures of A, B and C are to be given and the reactions are to be written.

Concept introduction:

The addition of hydrogen to double bonds in alkene takes place readily in the presence of metals like Pd, Pt, Ni etc. The double bonds in aromatic rings require stronger conditions for adding hydrogens. When oxidized with aqueous acidic KMnO₄, the double bond in alkene is cleaved to yield carbonyl compounds as products. A disubstituted carbon in double bond is oxidized to a ketone while a monosubstituted carbon in double bond is oxidized to a carboxyl group. If the carbon in double bond contains two hydrogens it will be oxidized to CO₂.

To give:

The structures of the compounds A, B and C and to explain the reactions.

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