- Addition of Hydrazoique Acid to Pseudoglycals Stereoselective Synthesis of L-Acosamine and L-Daunosamine
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Methyl and benzyl glycosides and glycal of L-acosamine (3-amino-2,3,6 trideoxy-L-arabino-hexose) have been stereoselectively prepared via 1,4-addition of hydrazoic acid to L-erythro-hex-2-enopyranose as a key step.Inversion of the C-4 configuration of met
- Abbaci, Belgacem,Florent, Jean-Claude,Monneret, Claude
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p. 667 - 672
(2007/10/02)
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- SYNTHESIS OF N-TRIFLUOROACETYL-L-ACOSAMINE, N-TRIFLUOROACETYL-L-DAUNOSAMINE, AND THEIR 1-THIO ANALOGS
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A simple and efficient route to N-trifluoroacetyl-L-acosamine (13), N-trifluoroacetyl-L-daunosamine (12), and their 1-thio analogues (18 and 20) is described.Stereoselective reduction of oxime 5 with borane, followed by trifluoroacetylation resulted in the arabino methyl glycoside (8), which, on mild acid hydrolysis gave N-trifluoroacetyl-L-acosamine (13) in an overall yield of 33percent, based on L-rhamnal (1).Upon oxidation of the C-4 hydroxyl group and stereoselective reduction of the resulting ketone 11, compound 8 of L-arabino configuration was converted into N-trifluoroacetyl-L-daunosamine (12) in a one-flask sequence with an overall yield of 28percent calculated for 1.Benzyl 1-thio-N-trifluoroacetyl-α-L-acosaminide (18) was synthesized from enone 2 on Michael-type addition of phenylmethanethiol, followed by oximation, stereoselective reduction with borane and subsequent trifluoroacetylation. 4-O-Acetyl-1-S-acetyl-N-trifluoroacetyl-1-thio-β-L-daunosamine 20 was prepared from 12 via the corresponding glycosyl chloride derivative.
- Pelyvas, Istvan,Hasegawa, Akira,Whistler, Roy L.
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p. 193 - 204
(2007/10/02)
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