Synthesis of pratensein, 5,7,3′-trihydroxy-4′-methoxyisoflavone

✍ Scribed by E. Wong

• Publisher: Elsevier Science
• Year: 1963
• Tongue: French
• Weight: 118 KB
• Volume: 4
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)90597-0

✦ Synopsis

Previous work' in this laboratory on the oestrogenic constituents of red clover (Trifolium pratense) has resulted in the isolation of a new isoflavone, C,6H,206, for which the name pratenseln was proposed.

On the basis of micro-degrative and paper chromatographic evidence its constitution was assigned as 3,7,3'-trihydroxy-4'-methoxyisoflavone (IV,R,H)*.

In view oi the very small amount of material available (~a 40 mg. from 36 kg.

of fresh clover) it was felt most desirable to synthesize the substance, both to confirm the structure and to make it accessible for phamBcologica1 study.

Pratensein has now been synthesised from the deoxybenzoin (III) by ring cyclisation with ethoxalyl chloride, following the general method for polyhdroxyisoflavones due to Baker and Ollis'.

1 E. Wong, J. Sci. Food Anric. I&, 304 (1962). 2 E. Wong, ghem. & Ind. (London), 1963 (1961).

3 W. Baker and W. D. Ollis, Nature a, 706 (1952);