One-pot synthesis

This is much desired by chemists because avoiding a lengthy separation process and purification of the intermediate chemical compounds can save time and resources while increasing chemical yield.

Sequential one-pot syntheses can be used to generate even complex targets with multiple stereocentres, such as oseltamivir,[1] which may significantly shorten the number of steps required overall and have important commercial implications.

In one such procedure[2] the reaction of 3-N-tosylaminophenol I with acrolein II affords a hydroxyl substituted quinoline III through 4 sequential steps without workup of the intermediate products (see image).

The addition of acrolein (blue) is a Michael reaction catalyzed by N,N-diisopropylamine, the presence of ethanol converts the aldehyde group to an acetal but this process is reversed when hydrochloric acid is introduced (red).

The alcohol group is eliminated in presence of potassium hydroxide (green) and when in the final step the reaction medium is neutralized to pH 7 (magenta) the tosyl group is eliminated as well.

One-pot preparation of 7-Hydroxyquinoline