3-Amino-3,4,6-trideoxyhexose

A similar reaction sequence without the last epimerization would yield D-abequose. CDP-D-tyvelose arises by C-2 epimerization of CDP-D-paratose.65a Other unusual sugars66-68 are formed from intermediates in Eq. 20-11. One is a 3-amino-3,4,6-trideoxyhexose in which the amino group has been provided by transamination67 (see also Box 20-B). 

Reviews have covered diastereoselective nitro-aldol reactions for the synthesis of amino-trideoxyhexoses, and anionic conjugate addition reactions of unsaturated nitro-sugars. Azidonitration of conformationally constrained d-glucal derivatives yielded predominantly the D-gluco-isomers such as 57. The total synthesis of the antibiotic everninomicin, which contains the nitro-sugar evernitrose, is covered in Chapter 4. 

Uridine 5 -(2-acetamido-2-deoxy-a-n-gIucopyranosyluronic acid pyrophosphate) (36) was isolated from extracts of Achromobacter georgiopolitanum14Sa and Micrococcus lysodeikticus.149b The ester of uridine 5 -pyrophosphate with an unusual amino sugar, namely, a 2-acetamido-2,4,6-trideoxyhexose of unknown configuration, has... 

Examples for the use of acetals such as 3, of 3-nitropropanal (1), and of 3-nitropropanol (2) or its O-protected derivatives are given in the references.22-24 A recent, notable application from this group is a short, high-yield synthesis of l-acosamine,25 the arabino isomer of 3-amino-2,3,6-trideoxyhexoses that form part of many antitumor aminoglycoside antibiotics 26... 

Disregarding nonoxygen functional groups (amino, dimethylamino, and so on) only the 2,3,6-trideoxyhexoses were isolated from natural products. However, some of the isomeric trideoxyhexoses were chemically synthesized. Thus, the methyl a-glycosides of 3,4,6 - tr i de o xy - d - erj> f/ ro - he x o p y r a n o s e, 3,4,6-tri-deoxy-D-t/zreo-hexopyranose and 2,4,6-trideoxy-D-eryt/iro-hexopyranose were synthesized from methyl 4,6-dideoxy-a-D-xy/o-hexopyranoside via selective sub-... 

Sharon and Jeanloz86 describe the isolation of a crystalline 4-acetamido-2-amino-2,4,6-trideoxyhexose hydrochloride from Bacillus subtilis. 

From a polysaccharide of the Gram-positive organism BaciUus svbtilis, a related sugar has been isolated but not fully characterized it is a 4-acetamido-2-amino-2,4,6-trideoxyhexose. Another diamino sugar, a 2,6-diamino-2,6-dideoxyglucose, has been isolated from the antibiotic substance Neomycin. ... 

A related family of 3-amino-2,3,6-trideoxyhexoses, L-daunosamine (386), the carbohydrate component of anticancer anthracycline antibiotics, L-vancosamine (387), the carbohydrate component of the antibiotics vancomycin and sporaviridin, and D-ritosamine (388), the enantiomer of the carbohydrate component of the antibiotic ristomycin, has been prepared from ethyl L-lactate [119]. 

From Achiral Non-carbohydrates. - Epoxide 57, available from methyl sorbate by a chemoenzymatic synthesis (Ono et ai, Tetrahedron Asymmetry, 1996, 7, 2595), was used in the construction of a set of isomeric 3-amino-2,3,6-trideoxyhexoses. Addition of benzylamine to the a,p-unsaturated add moiety before or after opening of the epoxide ring led to the D-acosamine derivative 58 or the lactone 59, respectively (Scheme 17)." Lactone 59 has previously been converted to L-daunosamine and D-acosamine derivatives (Vol. 14, p. 72, ref. 14). 

In a model study towards the synthesis of 4-amino-2,3,6-trideoxyhexoses, the a,P-unsaturated ester 60 and related derivatives proved excellent substrates for enantio- and regio-selective Sharpless asynmietric aminohydroxylation (Scheme IS). ... 

Several rare amino sugars have been found in antibiotics. From puro-mycin (Achromycin), 3-amino-3-deoxy-D-ribose has been isolated by Waller and co-workers 260). The configuration of the amino sugar was confirmed by its synthesis from L-arabinose, with methyl 2,3-anhydro-i -L-ribopy-ranoside 261) as an intermediate (p. 392). Among the hydrolysis products of erythromycin, obtained from Streptomyces erythreus, is an amino sugar with the empirical formula CsHnNOs. Its structure has been partially determined as a 3-dimethylamino-3,4,6-trideoxyhexose 262). On hydrolysis... 

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