{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Ch_322b_17.06 - Chapter 17.6 lecture note

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Reactions Related to the Aldol Condensation The Perkin Condensation In 1868, the young English chemist W.H. Perkins (1838-1907) discovered the important condensation reaction between ortho-hydroxybenzaldehyde (salicylaldehyde) and acetic anhydride. The product called coumarin is found in nature in lavender oil and sweet clover with the odor of new-mown hay. The discovery launched a new industry of synthetic flavoring agents and perfumes tied to the rapidly developing field of organic chemistry. The Perkin condensation is illustrated by the example below. CH O = + CH 3 COCCH 3 O = O = benzaldehyde acetic anhydride CH 3 CO 2 K 140 o C CH =CHCOOH 3-phenylpropenoic acid (cinnamic acid)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
A Mechanism for the Perkin Condensation The initial step is similar to the aldol reaction in that an enolate anion of acetic anhydride is formed in low amounts in an acid-base reaction. CH 3 COCCH 3 O = O = + CH 3 CO 2 - acetic anhydride pKa ~ 22 acts as base CH 2 -COCCH 3 O = O - enolate anion + CH 3 CO 2 H acid-base reaction
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}