| Abstrakt: |
Euchrenone a ( 7) isolated from the roots of Euchresta japonica has been synthesised from 3-prenylphloroacetophenone ( 1) by other workers. We carried out its cyclodehydrogenation with dichloro dicyano quinone (DDQ) to obtain 6-acetyl-5,7-dihydroxy-2,2-dimethylchromene ( 2) which was ethoxymethylated in the 7-position to give 6-acetyl-7-ethoxymethoxy-5-hydroxychromene ( 3). Chalcone condensation of 3 and 4-ethoxymethoxy-3- C-prenylbenzaldehyde ( 4) gave 4,6′- bisethoxymethoxy-2′-hydroxy-6″, 6″-dimethyl-3- C-prenylpyrano (2″, 3″-4,3) chalcone ( 5) which cyclised with methanolic sodium acetate to give protected 5,4′- bisethoxymethoxy-6″, 6″-dimethyl-3′- C-prenylpyrano (2″, 3″-7,8) flavanone ( 6). Deprotection of 6 with 4% methanolic HCl yielded ( 7) with melting point and spectral data identical to that of the natural compound. [ABSTRACT FROM AUTHOR] |
