Sodium borohydride → HCID 20326287, compound

Participants

Reaction Steps

To a solution of 10 g of crystalline antibiotic X-537A in 500 ml of absolute ethanaol was added 1.36 g of NaBH4. The reaction was followed by assaying with thin layer chromatography (silica gel - CHCl3 /acetone 8:2) and the reaction was continued overnight after adding an additional 1.0 g of NaBH4. The following morning the solvent was removed under reduced pressure and the heavy oil diluted with methylene chloride, washed with dilute HCl, dried (Na2SO4), and concentrated to a solid foam. The slightly pink solid was chromatographed on a 500 g silica gel column eluting with 2 l. hexane-methylene chloride (1:1), 2 l. methylene chloride 2 l. methylene chloride 2 l. methylene chloride ether (1:1). The 250 ml fractions were assayed by TLC and fractions 13-17 pooled, concentrated to a yellow solid and rechromatographed on a 150 g florisil column eluting with a gradient from hexane to acetone. The fractions containing 3-methyl-6-{4,6-dihydroxy-3,5-dimethyl-7-ethyl-7-[5-ethyl-3-methyl-5-(5-ethyl-5-hydroxy-6-methyl-2-tetrahydropyranyl)-2-tetrahydrofuryl]heptyl} salicylic acid were pooled and concentrated to a small volume from which pure 3-methyl-6-{4,6-dihydroxy-3,5-dimethyl-7-ethyl-7-[ 5-ethyl-3-methyl-5-(5-ethyl-5-hydroxy-6-methyl-2-tetrahydropyranyl)-2-tetrahydrofuryl]heptyl} salicylic acid crystals were recovered, m.p. 151°-153°. From the mother liquor, additional material was crystallized, [α]D25 +0.83 (C=.60%, CH3OH).

Provenance & Evidence