Structural analogs of flavopiridol {2-(2-chlorophenyl)-5,7-dihydroxy-8-[(3S,4R)-3-hydroxy-1-methyl-4-piperidinyl]-4-chromenone} are attractive as potential antitumor drugs [1]. They can be represented as a chrysine flavonoid in which the C22 H is replaced by Cl; the C8 H, by a N-containing heterocycle (3-hydroxy-N-methylpiperidine in the case of flavopiridol). However, known methods for synthesizing flavopiridol analogs [2, 3] are complicated and multi-step. Therefore, the successful electrochemical synthesis of biflavonoids and their N-containing analogs [4,5] allowed us to propose that it can be used to synthesize new flavopiridol analogs.Chrysine (0.254 g, 1 mmol, Aldrich) was dissolved in MeCN (250 mL), treated with LiClO 4 (0.110 g) and morpholine (0.520 mL), and electrolyzed in a diaphragm cell at a Pt anode with a working surface of 2 cm 2 and current 12 mA. KCl (0.5 g) was mixed with the anode liquor after 3 h of electrolysis, which then was continued for 2.5 h. When the electrolysis was finished, about 90% of the solvent was distilled from the anode liquor. Two red pure compounds were isolated from the residual by column chromatography (Porokvarts PKN-200, CHCl 3 -EtOH, 80:20 v/v, 5 mL/min).The yields of 1 and 2 calculated for starting chrysine were (0.17 ± 0.01 g, 45.2 ± 1.5%) and (0.13 ± 0.01 g, 34.6 ± 1.5%), respectively.
5,7-Dihydroxy-8-morpholino-2-(2-chlorophenyl)-4H-chromen-4-one (1). C 19 H 16 NO 5 Cl, mp 241 r 3qÑ, [D] D 20 +52.7q (c 0.35, MeOH). UV spectrum (MeOH, O max , nm): 210, 305, 346. IR spectrum (KBr, Q max , cm -1 ): 3615, 3340
