L-Decilonitrose2 (1, 2,3,6-trideoxy-3-C-methyl-3-nitro-L-ribo-hexose)
is the latest methyl-branched nitro sugar to be found as an antibiotic component. Other members of this novel group of sugars are L-evernitrose3 (2, from the evernino-micins4), D-rubranitrose5 (3, from rubradirin6), and D-kijanose' or D-tetronitrose* (4, from kijanimicin7,9 and tetrocarcins A and B'O). Syntheses of 211,**, 31,13, and a derivative of qsJ4 have been reported.
Decilonitrose (1) is a component of the new anthracycline antibiotics decilorubicin15 and arugomycin16 produced by Srreptomyces virginiae MF-266-g4 and Strept. violochromogenes lO!JS-AV2, respectively. Methanolysis of decilorubicin yielded methyl P-L-decilonitropyranoside2 (5) among the sugar components. The structure 5 was indicated initially by spectroscopic evidence and was confirmed subsequently by synthesis 2. We have recently used methyl 3-acetamido-2,3,6-trideoxy-3-C-methyl-a-L-ribo-hexopyranoside (6) in syntheses of 717, a derivative of 3-amino-2,3,6-trideoxy-3-C-methyl-L-xylo-hexose (the methylbranched amino sugar18 of antibiotic A35512B19), and t-rubranitrose13 (the enantiomer of 3). Interchange of the acetamido group at the tertiary centre of 617 with a nitro group would transform 6 into methyl cu-L-decilonitropyranoside ( 9), thus providing a useful, alternative route to a derivative of 1. This was accomplished by N-deacetylation of 6 with calcium in liquid ammonia20, and oxidation of the resulting amine 8 with m-chloroperoxybenzoic acid in boiling dichloromethane. Methyl cr-L-decilonitropyranoside (9) was obtained crystalline in 31% yield from 6. As in the synthesis of the p-anomer 52, the oxidation step was less efficient than usual for this type of amine.
Such nitro sugars as 9 would be susceptible to base-catalysed epimerisation at C-3 and/or C-4 via a retro-Henry reaction and recyclisation. Although potassium *Branched-chain Sugars, Part XIX. For Part XVIII, see ref. 1. **TO whom enquiries should be addressed.