Reduction of ketones to epimeric alcohols with potassium hydroxide-diethylene glycol

Selective transformations of friedelanes isolated from cork smoker wash solids

Friedelin (1) and 3-acetoxyfriedel-3-en-2-one (4), commonly known as friedelane triterpenoids, have been isolated from cork smoker wash solids (also known as black wax) on a multi-gram scale. These compounds are valuable starting materials for the synthesis of new friedelane derivatives. Stereoselective reduction of friedelin by treatment with LiAlH4, sodium, or catalytic hydrogenation results in the formation of both isomers of friedelinol (5 and 7) in excellent yields. Similarly, the reduction of 3-acetoxyfriedel-3-en-2-one gave epi-cerin (14) and a series of isomeric 2,3-diols or α-hydroxyketones. These transformations provide the most straightforward and convenient methods for the synthesis of A-ring functionalised friedelane derivatives using easily accessible starting materials.

Constituents of Bidens pilosa L.: do the components found so far explain the use of this plant in traditional medicine?

The dried aerial parts of Bidens pilosa L. were extracted with petrol ether, chloroform, methanol, and methanol/water. The petrol ether and the methanol/water extracts showed some antimicrobial activity. Fractionation of the extracts yielded well known substances, most of which have, however, not yet been described as constituents of Bidens pilosa. Several of these substances have previously been shown to be biologically active. Thus, phenylheptatriyne, linolic acid and linolenic acid have antimicrobial activities. On the other hand, friedelin and friedelan-3 beta-ol, as well as several of the flavonoids found are anti-inflammatory agents. The detection of these compounds in extracts from B. pilosa may rationalize the use of this plant in traditional medicine in the treatment of wounds, against inflammations and against bacterial infections of the gastrointestinal tract.