title: Regioselective intramolecular ring closure of 2-amino-6-bromo-2,6-dideoxyhexono-1,4-lactones to 5- or 6-membered iminuronic acid analogues: synthesis of 1-deoxymannojirimycin and 2,5-dideoxy-2,5-imino-D-glucitol.
abstract: 1-Deoxymannojirimycin (8c) was synthesised from 2-amino-6-bromo-2,6-dideoxy-D-mannono-1,4-lactone (7) by intramolecular direct displacement of the C-6 bromine employing non-aqueous base treatment followed by reduction of the intermediate methyl ester. Likewise, using aqueous base at pH 12, ring closure took place by 5-exo attack on the 5,6-epoxide leading to 2,5-dideoxy-2,5-imino-L-gulonic acid (9b), which was reduced to 2,5-dideoxy-2,5-imino-D-glucitol (9b). The method was further applied to 2-amino-6-bromo-2,6-dideoxy-D-galacto- as well as D-talo-1,4-lactones (14 and 15). However, only the corresponding six-membered ring 1,5-iminuronic acid mimetics, namely (2R,3R,4S,5R)-3,4,5-trihydroxypipecolic acid (2,6-dideoxy-2,6-imino-D-galactonic acid, 16) and (2S,3R,4S,5R)-3,4,5-trihydroxypipecolic acid (2,6-dideoxy-2,6-imino-D-talonic acid, 17), were obtained. The corresponding enantiomers, L-galacto- as well as L-talo-2-amino-6-bromo-2,6-dideoxy-1,4-lactones ent-14 and ent-15, reacted accordingly to give the D-galacto- and L-altro-1,5-iminuronic acid mimetics, (2S,3S,4R,5S)-3,4,5-trihydroxypipecolic acid (2,6-dideoxy-2,6-imino-L-galactonic acid, ent-16) and (2R,3S,4R,5S)-3,4,5-trihydroxypipecolic acids (2,6-dideoxy-2,6-imino-L-talonic acid, ent-17), respectively.
authors.affiliation: Department of Chemistry, Technical University of Denmark (DTU), Building 201, DK-2800, Kgs. Lyngby, Denmark.
authors.forename: Birgitte M
authors.initials: BM
authors.lastname: Malle
authors.forename: Inge
authors.initials: I
authors.lastname: Lundt
authors.forename: Tanja M
authors.initials: TM
authors.lastname: Wrodnigg
mesh_terms: D017485:1-Deoxynojirimycin / Q000138:chemical synthesis* / Q000737:chemistry; D000143:Acids / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D017605:Bromine Compounds / Q000737:chemistry*; D003500:Cyclization; D007783:Lactones / Q000737:chemistry*; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D013012:Sorbitol / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism; D014574:Uronic Acids / Q000737:chemistry*
chemical_list: C513881:2,5-dideoxy-2,5-imino-D-glucitol; D000143:Acids; D000588:Amines; D017605:Bromine Compounds; D007783:Lactones; D014574:Uronic Acids; C530349:iminuronic acid; D017485:1-Deoxynojirimycin; D013012:Sorbitol; D010100:Oxygen