Acetone → 8-Ethyl-1,6,7,8,10-pentahydroxy-7,8,9,10-tetrahydrotetracene-5,12-dione

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Reaction Steps

The resulting broth (about 12 liters) was similarly subjected to acid hydrolysis, acetone extraction from the mycelia and chloroform extraction, and finally 9.8 g of a crude powder containing β-isorhodomycinone. The whole amount of the crude powder was dissolved in 100 ml of methanol and the insoluble materials were centrifuged off. After concentration, the soluble fraction was applied on a silica-gel column (diameter: 78 mm) packed with 300 g of the above-mentioned silica-gel C-200 in chloroform, and eluted with 500 ml of chloroform, 100 ml of a mixture solution of chloroform/methanol (500/1), 3400 ml of the mixture solution (400/1) and 1000 ml of the mixture solution (300/1) in this order. β-isorhodomycinone was eluted with a mixture of chloroform/methanol (400/1). The β-isorhodomycinone-containing fractions were collected and evaporated to dryness followed by washing with ether The yield of β-isorhodomycinone was 0.62 g. The identification of this compound was carried out by means of 1H--M=NMR and 13C--NMR spectra and UV and FD mass spectra thereof, referring chemical data described in the literature (Chem. Ber., Vol. 98, page 3145, 1965).

Provenance & Evidence