title: A precursor to the beta-pyranosides of 3-amino-3,6-dideoxy-D-mannose (mycosamine).
abstract: SN2-type reaction of 3-O-(1-imidazyl)sulfonyl-1,2:5,6-di-O-isopropylidene-alpha-D-gluco furanose with benzoate gave the 3-O-benzoyl-alpha-D-allo derivative 2, which was hydrolysed to give the 5,6-diol 3. Compound 3 was converted into the 6-deoxy-6-iodo derivative 4 which was reduced with tributylstannane, and then position 5 was protected by benzyloxymethylation, to give 3-O-benzoyl-5-O-benzyloxymethyl-6-deoxy-1,2-O-isopropylidene-alpha -D- allofuranose (6). Debenzoylation of 6 gave 7, (1-imidazyl)sulfonylation gave 8, and azide displacement gave 3-azido-5-O-benzyloxymethyl-3,6-dideoxy- 1,2-O-isopropylidene-alpha-D-glucofuranose (9, 85%). Acetolysis of 9 gave 1,2,4-tri-O-acetyl-3-azido-3,6-dideoxy-alpha,beta-D-glucopyranose (10 and 11). Selective hydrolysis of AcO-1 in the mixture of 10 and 11 with hydrazine acetate (----12), followed by conversion into the pyranosyl chloride 13, treatment with N,N-dimethylformamide dimethyl acetal in the presence of tetrabutylammonium bromide, and benzylation gave 3-azido-4-O-benzyl-3,6-dideoxy-1,2-O-(1-methoxyethylidene)-alpha-D -glucopyranose (15). Treatment of 15 with dry acetic acid gave 1,2-di-O-acetyl-3-azido-4-O-benzyl-3,6-dideoxy-beta-D-glucopyranose (16, 86% yield) that was an excellent glycosyl donor in the presence of trimethylsilyl triflate, allowing the synthesis of cyclohexyl 2-O-acetyl-3-azido-4-O-benzyl-3,6-dideoxy-beta-D-glucopyranoside (17, 90%).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institut de Chimie Moléculaire d'Orsay, U.R.A. C.N.R.S., Université Paris-Sud, France.
authors.forename: J
authors.initials: J
authors.lastname: Alais
authors.forename: S
authors.initials: S
authors.lastname: David
mesh_terms: D000666:Amphotericin B / Q000138:chemical synthesis; D005960:Glucosides / Q000737:chemistry; D006027:Glycosides / Q000138:chemical synthesis*; D006031:Glycosylation; D006595:Hexosamines / Q000138:chemical synthesis*; D007093:Imidazoles / Q000737:chemistry; D008362:Mannosides / Q000737:chemistry
chemical_list: D005960:Glucosides; D006027:Glycosides; D006595:Hexosamines; D007093:Imidazoles; D008362:Mannosides; C014692:mycosamine; D000666:Amphotericin B