(+)-Daunomycinone → 4'-Deoxydaunomycin

Participants

Reaction Steps

A solution of 1.5 g of daunomycinone in 150 ml of anhydrous methylene dichloride containing 0.75 g of 2,3,4,6-tetradeoxy-3-trifluoroacetamido-L-threo-hexopyranosyl chloride (II), was vigorously stirred in the presence of 10 g of molecular sieve (4 A Merck) and 0.77 g of AgSO3CF3 in 20 ml of anhydrous diethyl ether. After two hours at room temperature, the reaction mixture was neutralized with a saturated aqueous solution of sodium bicarbonate and the organic phase, after being separated, was evaporated under vacuum to obtain a residue. The thus obtained residue was dissolved in 50 ml of 0.1 N aqueous sodium hydroxide, and after 30 minutes at 0° C the solution was adjusted to pH 3.5 and repeatedly extracted with chloroform to eliminate the unreacted aglycone. Then the solution was ajusted to pH 8.3 and extracted with chloroform until the chloroform extracts were no longer colored. The chloroform extracts were combined, dried over anhydrous sodium sulphate and concentrated to a small volume and thereafter acidified to pH 4.5 with 0.1 N methanolic hydrogen chloride. The addition of excess diethyl ether yielded 4'-deoxydaunomycin as the hydrochloride; m.p. 160°-164° C (dec). A sample of the product was subjected to thin layer chromatography (TLC) on Merck Kieselgel F254 plates using a chloroform-methanol-water (150 : 42 : 6 v/v) solvent system. The Rf of the compound was 0.47; [α]D20 = +296° (c = 0.05 CH3OH).

Provenance & Evidence