- A new efficient access to glycono-1,4-lactones by oxidation of unprotected itols by catalytic hydrogen transfer with RhH(PPh3)4-benzalacetone system
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Treatment of unprotected pentitols and hexitols with RhH(PPh3)4-benzalacetone system leads exclusively to glycono-1,4-lactones in 60-96% yield.
- Isaac,Aizel,Stasik,Wadouachi,Beaupère
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p. 475 - 476
(2007/10/03)
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- 2-Acetamido-2-deoxyaldonolactones from sugar formazans
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A new approach towards simple aldonic acid derivatives starting from the corresponding aldoses via the 2-acetamido-2-deoxy formazans resulted in the synthesis of 2-acetamido-2-deoxy-D-galactono-1,4-lactone (8), and its 6-deoxy (11) and 6-azido-6-deoxy (14) analogues on treatment with trifluoroacetic acid.The five-membered ring structure of the lactones and that of the intermediate lactone phenylhydrazone (7) was proved by 1H and 13C NMR studies, including deuterium-induced differential isotope shift (DIS) measurements.With sodium borohydride, lactones 8 and 11 were converted into 2-acetamido-2-deoxy-D-galactitol (15) and its 6-deoxy analogue (17), respectively.
- Zsoldos-Mady, Virag,Pinter, Istvan,Neszmelyi, Andras,Messmer, Andras,Perczel, Andras
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- Deoxyiminoalditols from aldonolactones; I. Preparation of 1,4-dideoxy-1,4-iminohexitols with D- and L-allo and D- and L-talo configuration: Potential glycosidase inhibitors
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1,4-Dideoxy-1,4-iminohexitols were prepared by a convenient two-step reaction from 2,6-dibromo-2,6-dideoxyhexono-1,4-lactones by treatment with aqueous ammonia and subsequent reduction of the carboxy function with sodium borohydride. By interchange of the reactions, the dibromolactones were reduced to 2,6-dibromohexitols, which by reaction with aqueous ammonia yielded the same imino compounds. Thus, from 2,6-dibromo-2,6-dideoxy-D-mannono- (1) and -D-glucono-1,4-lactone (9) the 1,4-dideoxy-1,4-imino-L-allitol (6) and -D-talitol (14) were prepared, respectively. These two compounds were also obtained from 2,6-dibromo-2,6-dideoxy-D-mannitol (5) and -D-glucitol (13), respectively, by reaction with aqueous ammonia. The enantiomeric 1,4-dideoxy-1,4-imino-D-allitol (18) and -L-talitol (22) were prepared similarly from the new 2,6-dibromo-2,6-dideoxy-L-mannono- (16) and -L-glucono-1,4-lactone (20), via the dibromo-L-hexitols 17 and 21, respectively. The ring closure of the dibromo compounds with ammonia has been shown to proceed via epoxides.
- Lundt,Madsen
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p. 714 - 720
(2007/10/02)
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