Synthetic receptor analogues: preparation and calculated conformations of the 2-deoxy, 6-O-methyl, 6-deoxy, and 6-deoxy-6-fluoro derivatives of methyl 4-O-alpha-D-galactopyranosyl-beta-D-galactopyranoside (methyl beta-D-galabioside).
The 2-deoxy (7), 6-O-methyl (15), 6-deoxy (22), and 6-deoxy-6-fluoro (31) derivatives of methyl beta-D-galabioside (1) have been synthesised. Thus, 7 was prepared by xanthate reduction using tributyltin hydride, whereas 22 was obtained by catalytic hydrogenation of a 6-deoxy-6-iodogalabioside. Regioselective monofluorination of methyl 2,3-di-O-benzoyl-beta-D-galactopyranoside with Et2NSF3 and subsequent alpha-D-galactosylation provided 31. Molecular mechanics calculations yielded similar conformations for 1, 7, 15, 22, and 31 with differences in phi H and psi H of less than 5 degrees. No indications of intramolecular hydrogen bonds, as displayed by 1 in the crystal, were found for 7, 15, 22, or 31.
Chemical Center, Lund Institute of Technology, Sweden.
J
J
Kihlberg
T
T
Frejd
K
K
Jansson
A
A
Sundin
G
G
Magnusson
D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000138:chemical synthesis*; D005690:Galactose; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008756:Methylgalactosides / Q000138:chemical synthesis*; D008759:Methylglycosides / Q000138:chemical synthesis*; D009904:Optical Rotation; D011971:Receptors, Immunologic; D013329:Structure-Activity Relationship
D004187:Disaccharides; D007202:Indicators and Reagents; D008756:Methylgalactosides; D008759:Methylglycosides; D011971:Receptors, Immunologic; C057031:methyl 4-O-galactopyranosylgalactopyranoside; D005690:Galactose