Q.18. - Organic Chemistry

Question

Question: Avobenzone is a conjugated compound that absorbs ultraviolet light with wavelengths in the 320–400 nm region, so it is a common ingredient in commercial sunscreens. Write out two different crossed Claisen reactions that form avobenzone.

Step-by-Step Solution

Answer

Answer

Step 1: Crossed Claisen reaction

Claisen reaction between two different esters or an ester and a ketone is named crossed Claisen reaction.

Crossed Claisen reaction between an ester and a ketone yields a β-dicarbonyl compound.

Step 2: Crossed Claisen reaction between a ketone and an ester

Crossed Claisen reaction

Step 3: Crossed Claisen reaction yielding avobenzone

The Claisen reaction between the carbonyl compounds provided below results in the formation of avobenzone.

The starting materials can be identified by cleaving the indicated carbon-carbon bond as shown below.

Compounds involved in the synthesis of avobenzone